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Control options with Vitodens 200 WB2B (Vitotronic 200 + Vitotrol 300) (125 Posts)
Control options with Vitodens 200 WB2B (Vitotronic 200 + Vitotrol 300)Hi,
I'm planning to have a WB2B-19 installed, with only one circuit - heating through steel panel radiators.
In terms of heat control, I understand that ODR + constant/permanent recirculation is beneficial and will offer a true 'cruise control' to a hydronic system. On the other hand, I am aware that due to technological constraints, the mod/con boiler cannot 'modulate down' too much (to comply with the reset curves and to consume only the minimum volume of gas necessary to satisfy the ODR model). I gues s for reasons as simple as too weak and un-stable flame.
Thus, an ODR-driven control would suffer of some "wrong impedance matching" problem at relatively warm outdoor temps. And I'm thinking that we could compensate for this "weak point" of ODR by using a room thermostat. Which would serve only the role of "high temp limiter", and with no setback.
The main goal is not to mess with the ODR (Vitotronic 200 + Vitotrol 300) logic at relatively low temps. But to help the system being more efficient (i.e. cut the gas off and the recirc pump completely) when the ODR cannot anticipate properly unusual gains of heat in the house (sun or simply the speed at which the heat leaves the house is much slower).
So, what I would like to to is to have a "bang-bang controller" such as Room Thermostat, which should turn the stuff off when the temp is too high (since the boiler cannot modulate too low, it will attempt to burn at a min rate and which is not optimal for the current demand and such too much gas will be consumed).
I was reading through numerous posts (especially those from Chris), and still I failed to understand how the Vitotrol 300 really works. It does have a temp sensor and we know also that it helps the Vitotronic 200 downstairs to get an internal temp feedback and shift the currently selected heating curve up or down. BUT the main question is: is Vitotrol 300 really capable of telling the boiler to come to complete stop? Does it have also a bang-bang type of control (on/off)?
The other questions would be:
-What is that Plug 143 (pins 2+3) meant for ("external blocking"). Chris is repeatedly explaining that it's not meant to be a TT. I understand that the other pairs of pins (1+2) serves a more complex purpose ("external demand" i.e. snow melting and forcing the boiler to be in "slave" mode and comply to some min water temp, and turn off some pumps, but only of a limited time). What about the "external blocking". Why can't it be used to tell the boiler to "stand by"? Also what kind of thermostat would be compatible with those pins? Is dry contacts expected or it's something that has power inherently?
-The same question about the mysterious Plug 96. Is that a reminiscence from the Vitodens 100 - used for line voltage thermostats from Europe (230V)? In our case 110V? Could that be used as a TT?
-Also, Chris was mentioning that it's possible to impose an upper limit to the modulation rate of the boiler (i.e. when you are oversizing the boiler for certain reasons, i.e. in his case his total heat loss was in the 40KBTU/h range but he wanted to have good DHW heating). In my case, I won't have DHW, only one primary heating circuit, and with a total heat load of 30-35KBTU/h (3.0/3.5gpm max flow rate). Maybe from a fuel cost savings perspective it would be nice to tell the boiler up-front not to goo too high with the gas valve? Is there a "Coding Level 2" setting for that?
-Are there any North-American standard, low-voltage thermostats compatible with Viessmann Vitodens 200 / Vitotronic 200? There are some which can offer also a pair of dry contacts, such as the eco-bee. It would be interesting to be able to drive both the heating (for Viessmann) and A/C (for a standard A/C system from North-America) via the same RT.
My main goal is to try to avoid using the Grundfos Alpha dP pump (which will be the only pump in the system) running when not necessary and also to have the boiler not firing unless the bang-bang 'controller' validates that the rooms do need heat.I wish to save energy overall. It seems a bit strange at first to try to marry an ODR principle with a RT (on a 1st view seems like 2 conflicting interests), or also trying an ODR + electronic TRV (i.e Danfoss Living ECO) scenario.
I appreciate your insights.This post was edited by an admin on April 7, 2013 9:53 AM.
Vitotrol 300Is an extension of the boiler control which acts like a thermostat. It will also provide the boiler with indoor temp feedback. Let the TRV's on the panel rads do their job and get the system running on constant circulation. The most efficient way to run the Vitodens. You can program set back, scheduling, have control of DHW and the control will provide any fault codes. Goes up in the living space on the wall where your normally your t-stat goes.
http://www.viessmann.ca/etc/medialib/internet-ca/pdfs/doc/vitotrol.Par.39908.File.tmp/Vitotrol_300_oi.pdf"The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
Why not having more flexibilityon Viessmann behalf by allowing the wb2b to be controlled also by an on/off thermostat?
I understand that it's aiming to use an 'European approach' / const circ based system. What about those situations whereas the boiler couldn't modulate down enough? It's bizarre that Viessmann wants us to follow only one single approach. It is very funny that there is a trend now in Europe completely opposite - people is trying now to save more on gas and electricity bills and complement their installations with an off/on room thermostat and other devices such as those from Danfoss, to completely stop both the boiler and the pumps.
If Viessmann is so stubborn with their "German mindset" and way of seeing things (i.e. inflexible) with their Vitotronic stuff, then I shall pass and maybe go with a Triangle Tube or other boilers. And this comes from someone originating from Europe.
I was hoping that some pros from this forum who have been working a lot with Viessmanns would shed more light on these aspects. Why so much secrecy and cryptic documentation from Viessmann?
Your Not Getting The SameVitodens in North America as you are in Europe. The installer across the pond has more control. The boiler even here is only going to fire if it needs to. Thus why we use a supply temp sensor. There is no "TT" on the boiler. You could use the 143 plug, ie, external demand if you want an on off system.
I don't understand the logic of wanting an on/off system especially with panel rads. With adding the Vitotrol you can program set point heating schedules. There is nothing hidden in the Viessmann manual. You just have to understand it.
In the next few months the new Vitodens 200 will be here featuring the same control being used in Europe as well as Vitocom giving you access to the boiler via IPhone, IPad, Andriod App. You can find the Vitotrol Showcase Demo in the ITunes App Store."The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
Here's the logic...that makes me believe that such on/off control is still needed (to complement the ODR, not to replace it): If it gets too warm outside (spring or autumn), even if the boiler is a condesing boiler and shoot to lower water temps, it's still having its limit. Including also how low it can open up/modulate the gas valve. In such situations, the boiler may be forced to deliver the water warmer than necessary i.e. a room thermostat or real thermometer will indicate higher room temp than the setpoint temp. So basically, the boiler will always burn a minimum volume of gas per hour, no matter what.
Is this scenario impossible and I should not be concerned about it? I am worried that the boiler will fire for too long cycles and with very little pauses in between. Like the situation that some of my neighbours is describing - they were promised that by getting a new, modern forced air furnace (employing ECM motor and modulating valve), that their heating bills will get 30% lower. And to their disappointment, that had never happened.
TRV's with VitotrolYou don't need a thermostat to run the Vitodens 200. Use the TRV's to balance the room temperature or use the Vitotrol if you must. The Alpha will work well with panel rads and the TRV's. Make sure the low loss header is used with sensor, if flow rate exceeds 6gpm.
The boiler comes with a sophisticated outdoor reset control. The boiler will idle when there is no demand or be in warm weather shutdown. The ODR can anticipate weather changes and if internal solar gain is an issue, the vitotrol 300 has an internal sensor that can be enabled, if desired. This is not a boiler that wants to be operated by a regular thermostat.
If installed correctly, the appliance will be very efficient and save fuel. Take the Viessmann Vitodens class at the Rhode Isl., Waterloo, Ont. or Surrey, BC locations if you really want to know how to maximize the efficiency of the appliance.
How the boiler will reactto the following scenario: The Vitotrol 300 (or the 300A model - available only in Europe, and which seems to be smarter design) is set to have a setpoint temp of 22 degree Celsius. Now, the ODR does its own calcs and also uses the indoor temp as feedback. What will the ODR do - will it always try to make the boiler modulate down and provide the lowest water temp possible, in such way that the target temp will never be achieved exactly indoor? In such way that it try as much as possible, to fire the gas as longest as possible?
OR there will be moments when the (real) indoor temp will get to 22.5 Celsius and then the boiler will stop firing for sure? I am concerned mostly about situations where - even with a low heat curve, the boiler will still fire in warm outdoor conditions. Because of that min modulation limit.
People in Europe have tried both the ODR and the on/off approach and they came up with the conclusion - strangely - that ODR will not bring the fuel costs down (albeit they admit the comfort is much better, because of - to use Chris' beautiful metaphor - the "hydraulic symphony"). They were saying that there are moments when you just need to tell the boiler to shut up. So, maybe we can combine the ODR with this "temp limit" approach. Someone else on the forum was quoting this excellent article:
and that article itself is admitting that ODR has its own problems when there is an imbalance between what was estimated and what the real speed of heat loss is (negative variances caused by winds and positive ones caused by sun, computers, persons in the room etc).
About the training in Waterloo: I have tried to get an answer from the Viessmann headquarters, and expressed my interest in attending their training session together with my father. But absolutely no reply from them. Why so much disrespect for the residential customers, I simply cannot comprehend. This looks like arrogance to me, or the result of this excessive "market protectionism" which seems to happen here in Canda. Honestly, I am starting to be very disappointed in Viessmann.
Also, please pardon my lack of experience in hydronics and maybe this forum is in fact only for you the pros - I am disappointed that there were some other questions asked in a previous thread, I have received good first-level replies but after that the discussion was simply left in limbo state.
It's too bad if it's all about money. I sincerely hope it's not the case.
Thanks a lot Paul. And also to Chris and Bob - you are all top notch guys.This post was edited by an admin on April 7, 2013 12:41 PM.
You Need To Understand ModulationThe boiler is going to modulate based on a few things. You would think it is all related to ODR but it is not. Temp Rise or Boiler delta-t is really the deciding factor. If you have a small temp rise the boiler knows your not extracting btu/hr. So she will be modulating low. As your emitters start pulling out the btu/hr and sending colder return water back she will increase the modulation rate and head towards high fire.
It's pretty simple..The boiler pump selection is critical. The pump you select is going to move the given flow rate at all times when piped pri/sec or using a LLH. It never changes. In the end the charts mean you need to move the given gpm at the given rise to get the full output of the boiler.
Here are the flow rates and pressure drop for the WB2B19.
20 Rise 6.1gpm @ 16' Head 6.1 x 20 x 500 = 61,000 Btu/hr
25 Rise 4.9gpm @ 12' Head 4.9 x 25 x 500 = 61,250 Btu/hr
30 Rise 4.1gpm @ 8' Head 4.1 x 30 x 500 = 61,500 Btu/hr
35 Rise 3.5gpm @ 4' Head 3.5 x 35 x 500 = 61,250 Btu/hr
40 Rise 3.1gpm @ 3.5' Head 3.1 x 40 x 500 = 62,000 Btu/hr
The only factor that can change the entire system btu/hr output delivery of the boiler is DELTA-T or TEMP RISE. Flow is constant and the value of 500 is constant (unless not 100 percent water).
So your question concerning how the boiler will react is predicated on the system side design and your boiler pump choice. You need 3gpm on the system side. Do you want a pump moving 6gpm across the HX because you can only take 3 away and the other 3 goes right back into the boiler return?
This isn't just Viessmann it's all condensing boilers when piped pri/sec or LLH. If I'm being honest the best choice for this little job is a Lochinvar Knight WH55 and utlitze the variable speed boiler pump option.."The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
Yes, the ODRis not the only deciding factor in the modulation. Obviously the boiler can also measure the water temp on the return side and understand that either the heat demand was fully satisfied, or to modulate the gas valve / supply water temp appropriately.
My question was what happens when the boiler sees a very low delta T between supply and return - will it decide to stop the firing completely, or stubbornly try a sort of minimum modulation and waste gas? It's puzzling that Viessmann's control board does not seem to provide an easier way to interface with on/off system. And that they want you to use the Vitotrol exclusively and we are not sure of how the room temp sensor is being used (i.e. if it can command the boiler/vitotronic to a full stop).
And when I was asking about thermostats, I was also thinking that - if one decides to go for Vitotrol 300 (or 200), s/he will have to keep a 2nd thermostat for the cooling system. It would be great if there is a solution to combine them both.
Chris, I understand the universal formula between BTU/h, flow rate and DeltaT. But I am puzzled as to why you have included in those sample figures the pressure drop? It's not influencing the BTU, right? You mentioned it only to help with the sizing of a circulator, if my understanding is correct?
True, for a heat load of 30,000 BTU/h and a 20F Delta-T (btw is a 20 delta appropriate for steel panel rads, or it's rather for baseboards?), a flow rate of 3gpm would be needed. So obviously, I would need only a pump which should supply 3gpm, right? And since there is only one circuit and a dP pump to be used, and 3gpm is well withing the Vitodens WB2B-19's allowable range, I guess not even a LLH would be needed.
I wanted to go with Viessmann because they are a well respected brand back to the other side of the pond (together with Vaillant). But it's bizarre that the control options are not similar. And also the fact that it cannot drive a system pump conditionally on demand. Let's say that by not integrating a pump inside, is not a super big issue because after all we can use the Alpha or the Bumblebee now, right? It would be great if they were able to drive those automatically. I guess that PMP module is very misleading - they have introduced it in the North-American model just because they wanted a step-up transformer and wished to not bother with re-designing the main boiler board and sensitive stuff such as the igniter/lambda pro.
I shall look into Lochinvar Knight WH55 - I know nothing about Lochinvar unfortunately :-)
Thanks again Chris.
The Knight WH55Whoaa, it seems to offer plenty of control options, and the docs are explaining them in plain, logical way. Looks like Lochinvar aimed for transparency with their product. Now, what about the reliability. Also, it will be hard to find it in Canada...
Thank you for the tip.This post was edited by an admin on April 7, 2013 7:02 PM.
It FitsYour application better. You don't have to pri/sec pipe, the boiler can control the system pump and you can have your on/off system. The fire tube HX is used on many boilers. It's the same as the Triangle. I know my friends at Viessmann look at all the post here where Viessmann is the subject. Sorry guys, it is a better fit for the application. Has a much lower end.
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Super.THANK YOU again for your advice.
ControlIt is funny to see how subject of thermostats , pumps control, night setbacks comes all the time up.people want control. It is simple, you do not need thermostat, you do not need night setback. You do not need zoning. You do not need control over the heating system. You need comfort and savings. Just set odr , TRVs , and forget about control. System will control itself. On 200 series system pump is controlled by pump module and gets turned on and off when boiler thinks it is necessary. This winter I had a chance to replace brand new German boiler from viessmann competitor. I did not have a chance to put my hands on those boilers and what shocked me is amount of configuration options not needed in real life and low build quality. I guess we get spoiled by viessmann products.This post was edited by an admin on April 7, 2013 11:06 PM.
I AgreeConstant circulation, especially this type of application is the way to go. If it was me I would just add the Vitotrol and let it rip. If I was concerned with short cycling I'd add the Caleffi 25 Gal ThermoCon Buffer Tank in lieu of the low loss header.
YepAt the tail end (hopefully!) of my first heating season with the new system I put in. No thermostat, no zones, no problem. House stayed remarkably well balanced and comfortable, even with three different emitter types (mostly radiant ceilings, one existing slab retrofitted with between-the-joist plates, and one room with homespun multi-pass forced convection.)
System pumpGennady, are you absolutely sure about your statement: "System will control itself. On 200 series system pump is controlled by pump module and gets turned on and off when boiler thinks it is necessary."? Is that based on your direct observation? Because otherwise neither of those 4-5 Viessmann docs is clear in that respect. Also, would the same behaviour be observed even when there is no separate boiler pump / P/S setup?
See fig 20From viessmann manual.
Here's Something to ComplimentWhat Gennady posted. I agree with him. The reason why Viessmann is so vague is that they don't want homeowners and non Viessmann contractors playing with their product. It's been that way since they came to the states.
P/sIt does not matter if ps or other config is chosen. You just pick one when configure boiler. A pump is a pump. Also you can see other info on page I just posted. D and E shows on and off system pump. Just my 2 cents.
ObservationI make a living installing those boilers. So far system pumps do not work in the summer on my viessmann installations. On another hand you worry too much. You will not figure out all problems you probably will encounter. And system pump operation will be probably smallest one. Good luck
What is your fire/no-fire ratioGordon, ok, assuming no thermostat and just letting the ODR + vitotronic 200 + vitotrol 300 driving the show, would you be able to tell how often and for how long was the boiler firing vs. not firing (and no pump driven for latter case)?
Are those people across the pond suddenly getting crazy in finding out that they are getting better fuel consumption and hydro bills by adding a thermostat and shutting the pumps and the boiler itself completely off when the (real) temp as indicated by the room goes above the setpoint?
(I wish to make clear that I have never mentioned in this thread that I would like a setback feature, at least one outside the Vitotrol's control - as Gennady somewhat seemed to imply).
What is wrong in having a thermostat being used as a "high temp limit", and for anything below that value it would not interfere with the ODR's logic.
Can you guarantee that Vitotrol's internal temp sensor can assume that 'high temp limiter' role? Why are Viessmann's docs so cryptic and not explaining to people what is that device really doing? I am more and more under the impression that ... it's just a remote control, and everything it does can simply be done by going downstairs and operate the Viessmann directly :-)
[btw, I don't know what's going on with the forum web site, I can no longer reply to a specific person's post]This post was edited by an admin on April 8, 2013 7:15 PM.
Which manual[sorry, again, I can't post anything new as direct reply to a specific person].
Gennady, about fig 20: which manual is it, because there are 4:
-Technical Data Manual
I'll open each of them and look for that Fig 35. I do recall seeing it - I can't see too much from your screen capture, but it was something explaining how the heat curves get adjusted and/or shifted up or down. And a "rectangular signal pattern' showed in the background, showing how the system pump or boiler pump is sequencing.
But never, ever mentioned black and white that the sys pump will stop when no fire.
You see, I never like fuzzy/unclear things.This post was edited by an admin on April 8, 2013 8:32 PM.
Pump regimeIn reply to "Observation - I make a living installing those boilers. So far system pumps do not work in the summer on my viessmann installations".
Well, that's a thing I know, that's fine. My question was not about the summer mode (or whatever abbreviation it has).
So the use case is the following:
-only one pump, system pump. Preferrably an Alpha Delta-P pump.
-ODR outdoor sensor
-Vitotrol 300 installed.
-pump connected to plug 20A in the PMP.
Now, once the heat is satisfied, I assume that the boiler will stop firing (even that question is unclear, to be honest. Because it looks like this ODR principle favors loooong firing cycles and less breaks/stops). But let's say it will eventually stop firing.
What will happen after 1-2 minutes of the 'stop firing' moment?
Will the sys pomp be commanded to stop via the 20A relay, or not.
I appreciate if you can answer this very simple, common sense question.
Thanks a lot in advance.
RE: "On another hand you worry too much. You will not figure out all problems you probably will encounter. And system pump operation will be probably smallest one. "
Well, my main worries are related to the diffs between the same Viessmann model sold in Europe vs. the one here. My father is good at installing the rads, piping them, manifold circuits, parallel reverse/return stuff, and basic boiler connection, including gas line. What drives us 'crazy' is the ambiguity in the manuals, why is Viessmann so 'uptight', can't figure. I have quite good command of technical things, and it's laudable that they at least provided some drawing for the main board. But they left some connections/their purpose quite ambiguous...Nobody can explain to me what the heck the plug #96, and 143 (terminal 2+3, not 1+2) do!This post was edited by an admin on April 8, 2013 8:31 PM.
I told You What BothPlugs do. 143 is external demand and 96 is jumped out. It is used across the pond to power accessories. Honestly, I wouldn't want you to instal a Viessmann boiler.
PlugsPlug 143 seems to serve 2 purposes: Terminal 1+2 is "external demand" and 2+3 is "external blocking". What does the external blocking do? Can you plug a dry-contact 'thermostat' there to tell the vitotronic/boiler to stop functioning? I'm not implying that I would do that, please don't laugh or discard my question. I am simply asking - wish to understand first.
Plug 96: shorted out. Ok. Is it an input or an output? Can't understand where that opto-coupler is driving. I presume it's for line voltage form of thermostats - the one like Vitotrol 100UTA/UTD which the former Viessmann 100 was using?
Ok, thanks for you opinion and understanding someone who wishes to understand and not being a pro like you guys. I was hoping that investing in the Viessmann, with my hard earned money,is enough. But no, it looks like we need to do more about it ;-)
One pumpI would never do this configuration for the reason it will not work. I do not want to go into discussion about why it will not work. It will not on most cases. You can show me some diagrams from viessmann or other any manufacturer. I just do not agreeThis post was edited by an admin on April 8, 2013 8:56 PM.
It's mentioned in the manualhence my intention to find more about it. Ok, you say it won't work. I trust that you know where it's appropriate to be used, and you consider that a dangerous knowldge. Ok, I understand. Thank you.
Figure 20Ok, it seems to be this manual:
Start-up/Service Instructions: http://www.viessmann.ca/etc/medialib/internet-ca/pdfs/doc/WB2B.Par.36997.File.tmp/Vitodens_200-WB2B_sm_si.pdf
I can see the "Room temperature setpoint adjustment" figures (Fig. 18 and 19) - page 32. There is no figure 20 on that page. The only Fig 20 exists on Page 60 - instructions on installing ODR sensor.
Even if the page 32 shows under regime "D" - Heating circuit pump “OFF”. It's still un-clear WHO sets the power off. Vitotronic or an external module from a zone valve system or other external (i.e. Taco) controllers? Why is it mentioned only like a 'by the way' ? :-)
I'm Leaving This Thread With One LastBit of information. Your way over thinking your entire project. You have a constant circulation system screaming at you. Either take advantage of it or move on to a boiler that will give you what you want.
You can morph a Vitodens into bang bang operation. Just turn off the supply sensor in Coding 2 and use external demand (143 plug). Now you have an Amercian On/Off Boiler. Best of luck..
Bang bangThank you Chris. But please don't take it the wrong way. I was not implying that I would like to go with a pure bang-bang mode. I was seeing rather as a complementary factor (like an upper temp limiter if you wish - like a guarantee). For the 'normal' operation, when the boiler would nicely work below that temp, the ODR logic wouldn't be affected.
And overall, I just wanted to know what the Vitotrol 300 is really doing, if it can offer that function by itself, that's all. Understanding the options first, and then selecting the strategy.
If I can know that the PMP via plug 20A can start or stop the external system pump (and not only in summer regime, and in a circuit without mixing valve), and that Vitotrol is a good folk and telling something VERY common sense and civilized to the boiler (like, hey buddy, you went too far, please STOP, don't try to modulate down, because you cannot anymore, so stop firing!), then I will be a very happy person and not use the bang-bang.
Again, don't get me wrong, it's not that I like on/off - on contrary my existing forced furnace works like that, and I hate it with passion. That's why I desperately want to go for this hydronic project, why are these house builders fooling the people with the forced air - don't know but one reason for sure is the money (cheaper and more profits for them).This post was edited by an admin on April 8, 2013 9:20 PM.
ReasonI question your reason for posting here. On one hand you asking to explain how system would work in very simplistic and poor configuration, on another hand you asking questions about functions you never will be using unless you will be building complicated Mixed temperature levels loads. I find it very strange and fruitless. We all try to help you if you really need help. But seems you have another agenda.
tell us more about your projectwhat kind of distribution system are you thinking about?
Distribution systemWe are thinking about using a manifold, eventually combined with parallel reverse/return for certain rooms (especially 2nd floor) where we would want fewest piping to be visible as possible.
We won't be using monoflow tees/diverting stuff.
I was inclining towards using pex-AL-pex, but my father is keen to using copper. In Europe, pex-AL-pex was the 'rage' for the last 15-10 years. But due to poor quality pipe being supplied (to Central/Eastern Europe at least), there were incidents where many pipes simply blew up. And people over there simply oriented towards copper now. It's funny - the opposite is just happening here in North-America.
Your heat load is 30-35k max?What is the min. modulation on the vitodens you're looking at?
MinIs 31 ...Sure direct pipe it...It's not the boiler for the application he wants. He changes his tune across every corner. Better off with the Loch WH55 and it's lower turn down..
People want a more verbose explanation.This is fun stuff.
ContextDear Gennady, rest assured that I have no other 'agenda'. I am a hardworking person and wish to get a reasonable hydronic system installed and looking for some sort of 'assurance' that I'm on the right track with this Viessmann boiler solution. I simply wish to know if my money will be used wisely or not.
I thought that my use case and questions were down to Earth and not academic.
The use case was very simple:
-poorman's one heating circuit (no p/s)
-modest heat load needs (30K-ish)
-one single circ pump
-odr and Vitotrol in place
-pump driven by the plug 20A in PMP module.
And outside is not summertime, let's say it's -10 degrees Celsius. There is a head demand, the boiler stars firing. System pump is (or becomes?) on. After a while the heat demand is satisfied. The boiler stops firing. Will the pump stop after a while, until the next firing cycle or not?
Loch WHN-55Is the boiler for this application. I told you that before.
okso, as you indicated originally, your have made that recommendation due to many factors, right? Heat load, smaller 'hydraulic resistance' through the boiler's internal, automation possibilities, right?
Shall I presume Chris that you intrinsicly implied that, it's not the fact that the Vitodens cannot accept on/off commands from an external agent (or it can but it's not the preferred use case, to be a 'slave' :-) ), but the fact that even for a simpler form of command - like driving the power to the pump conditionally (driven by its own factors, not external factors, mind you) - it is not able to achieve that, right?
Thank you for explaining and re-confirming. I'll try to go with the Lochinvar Knight them. If I can't source it, I'll have to use the Viessmann, so there is still hope for it, rest assured!
Look You WantBang, Bang and are worried about swing seasons. The Loch allows you to control the pump via 0-10VDC and has a lower btu/hr output. So it will give you the best of all worlds for your application. No pri/sec piping needed.
What your missing is you have the opportunity to run constant circulation with indoor temp feedback with communication direct to the boiler. You feel that an external switch is a better way, so go for it..
You can use indoor feedback...but you have to buy another box.
No He Doesn'tWould just need to get a Vitotrol 300 which an extension of the boiler control and about the same cost as a Honeywell Prestige Thermostat...
No I mean for the Loch...The boiler can except a 0-10v modulation signal from say a Tekmar or Honeywell unit.
0..10V input signalTrue, but that would be doing a rather more complex thing. It will basically make the Viessman act like a slave and modulate at the rate proportional to that DC input voltage.
Chris is right, one should see that as serving another purpose. Because we don't want to give up the built-in control/intelligence of the vitotronic 200, as far as a 'ODR driver' is concerned.
(sorry, I was referring to Viessmann's case - note that Viessmann has that too).
But in Lochinvar's case, it can be done easier - just by using one or all three thermostat inputs. Again, if the Knight will consider those signals as "high temp limiters' and not affecting blindly the odr-driven logic, then it's fine.
Who knows, to me Vitotrol 300 is still mystery. Maybe it does what's supposed to do (high limiter) but the docs are not explaining it enough. We have to get the input from someone who actually owns it. If that's the case, then my apologies for being too circumspect/paranoid :-)This post was edited by an admin on April 8, 2013 10:38 PM.
high temp limitersWork just fine, but occupants need to be educated (and usually reminded) of their function. Leave them ~2-4ºF above the indoor design temp and then carefully tune the curve. Mind the deadband on the stats -- it can really mess you up.
And nowmaybe we can get in more understanding of what Vitotrol 300 is doing?
How is the vitotronic 200 downstairs making use of the built-in temp sensor? Used only to shift the curve up or down? Or if I grab a real thermometer, after a few cycles, I'm going to read the same temp as what Vitotrol 300 was set to, as setpoint temp? Is the temp set through that only a 'hint' ?
The VitotrolIs an extension of the boiler control with the feature of giving the boiler indoor temp feedback which the boiler uses to adjust it's curve based on the outdoor temp, indoor temp in adjusting the supply water temp.
With constant circulation and panel rads with TRV's it is a homerun. The only issue is the low end btu/hr. It doesn't fit your application unless you want to invest in a Caleffi ThermoCon 25 Gallon Buffer tank in lieu of the LLH.
GreatExcellent, so you are happy with your current setup, and what the vitotrol indicates, with a proper heat curve selected (based on a trial-and-error long term observation), it will roughly indicate the same as a thermometer in that room?
Thank you Chris for explaining it.
smihailaI'm curious as to how long you would think that the boiler should be shut off for? The boiler would be attempting to provide just enough heat to compensate for the loss from the structure. It can't be more efficient than that. You would be interfering with that, causing the sytem to cool, and then cause it fire higher than normal when it restarted, and sacrificing efficiency. It is not a snapshot, it's a dynamic process.You seem to think the boiler would over-heat the house, and that is just not the case. You keep applying "Old School" thought processes to this new technology.
It can't bethat I am applying 'old school' to this technology. Simply because it's been only 9 years so far since I'm here in Canada :-) I was born, grew up and educated back in Europe. So, I grew up mostly with the constant circulation use case. At least in my parents' apartment. But to be honest, I do recall that the pump (integrated in a Vaillant) was not running all the time - after the fire ceased, it was running for 5-10 minutes (I guess because it's still having water good to be moved around, to transfer energy in the rads). And then it stopped. Without any on/off external thermostat of any kind.
My question about fire/no-fire rates is in this context - to explain it better: I see no issue in the boiler firing for very long periods (even non-stop) - if, and only if - according to the estimated load/ODR, it can modulate the valve gas as lowest as possible to achieve that target. Not more, no less. To achieve optimum fuel consumption (well I guess that corelates also with condensing range and other efficiency factors).
IF it's a bit warmer outside, or the heat inside the house doesn't lose at the estimated speed and stay more inside, then my assumption was that the boiler wouldn't be able to modulate so low (i.e. less than 30%?). If it can stop in that case, FINE. If want to put more heat in, it will be wasting fuel, am I missing something?
What you're missing...The boiler's ODR control will, when properly adjusted, tell the boiler to maintain just the right supply water temperature to allow your emitters to compensate for the heat loss - no matter how small the heat loss. If there's no heat loss - that is, the outdoor temp is close to or above the desired indoor temp - warm weather shutdown kicks in, and space heating (including space heating circulator) will turn off.
The boiler's burner modulation control will, if possible, maintain the correct firing rate to keep the supply water temperature at the setpoint that the ODR control tells it to maintain. If it can't turn down low enough, it will turn the burner off completely for a little bit of time in order to provide, on the AVERAGE, the supply water temperature equal to the ODR setpoint. While the burner is turned off, the circulation continues, as it should.
So, let the boiler's controller do its job. The only reason to have a thermostat is to make up for the case where your ODR curve is set too high for the conditions. Basically, it's a very crude and one-sided form of indoor feedback (can't bump up temperature in case the ODR curve is too low, for instance.)
hi smihailaAre you making any progress smihaila?
yesGordon's last post about how the boiler reacts to the odr and indoor feedback is more encouraging.
The only part that still puzzles me is this statement: "If there's no heat loss - that is, the outdoor temp is close to or above the desired indoor temp - warm weather shutdown kicks in, and space heating (including space heating circulator) will turn off."
So, shall I understand that there won't be any situation whereas the outdoor temp is still considerably below desired target indoor temp, and the boiler will be impossible to be in "turned off" state? This would mean the following: The boiler is able to adapt to the hot water needs so well (no matter how big difference between outside and inside), that not only it can maintain a firing rate, but ALSO with the most optimal volume of gas being burned (even in low modulation)? If that's the case, then it's amazing.
Maybe Gordon's example was on the extreme side (when we get into WWS mode). And in reality the boiler should, and can, stop also in other situations. This would be in sync with the next statement: "If it can't turn down low enough, it will turn the burner off completely for a little bit of time in order to provide, on the AVERAGE, the supply water temperature equal to the ODR setpoint." That's fine with me if it's like that.
The only "oddity" is the fact that, during the fire-off period, the pump will always work, instead of, let's say, working only 3-4 more minutes since the moment of time the boiler ceased firing. Because what purpose serves to recirc water which in the meantime gave up all its heat energy into the rad circuit and now it's cold? That's how I remember it working back in my former apartment anyway.
I am ok with ODR, I find it in fact the answer to the temp fluctuations and 'holes' that I am now having with my strange forced air blower. And (besides the pump) I'm puzzled about the recent impression from people across the pond, who are saying that their fuel consumption average is still lower when they complement the odr setup with a thermostat....:-) It's funny, because they say that they are happy sometimes with the boiler firing less often but working for longer. Maybe they are referring to the warm temp case (spring or autumn). Otherwise it doesn't make sense, unless there is something wrong with their boilers and can't modulate low enough and waste small fuel volume.
Just to give you an example: right now, at in Central/Eastern Europe is kind of warm. And a guy was very happy that in his apartment the boiler was firing only 4 or 5 times per day and when it was firing, it kept firing for about 45 minutes to achieve the target temp. Imagine that he was very happy - he tested the both scenarios (continuous run, no thermostat vs. his latter approach) and he said that we was able to drive the consumption down to as low as 2-2.5 cubic meters of natural gas per day :-)This post was edited by an admin on April 9, 2013 9:09 PM.
GuysHe is wasting all of our time, effort and advice. He's called everyone he can to try and get a boiler as cheap as he can. Suggest he finish where he started with ecomfort.com. Yes my vines run deep and you cannot dig deep enough to get away from the roots.
Like I recommended prior. Go buy a Lochinvar Knight WHN-55. It would be in your best interest and honestly ours..
sorryif that was the impression that I have left. I admit that I am a bit stressed out, as I need to balance between my stresfull day-to-day job and also this project.
Sorry if I have offended anyone - it was never my intention.
Thank you all for your help and advice. I believe I have a better understanding now, thanks to you.
[I'm not trying to be cheap, I'm just looking for a good value for my money. We are a modest family of 4, with myself the only breadwinner in the house. I have no car, going to work by bus or bike. But no mortgage and no debt at all. This without any help from anyone - we don't even have any relative here. We try to leave withing our means, and saving as much as you can from these greedy Governments and banksters]
Value?Your looking for free education to purchase from an internet peddler. Your not looking for value because if you were you'd pay for it. Your questions go way beyond someone looking to make the right decision. Your pushing for a design and control strategy.
I didn't take it that way, ChrisIt's a different world we're living in now from the one in which we grew up. Information (whether true or misleading) spreads much more rapidly. I think we'd be lying if we said that we've never benefited from someone (or ones) sharing knowledge freely - heck, seems to me that this is what this site, and others like it, is all about. I don't think that the OP is looking for someone to design his system for him, he's groping for understanding of how things work. You've been very generous with sharing your knowledge, but know your limits and don't participate beyond the level with which you're comfortable. Internet peddlers are here to stay. As, I believe, are knowledgeable and adaptable distributors who provide real added value to justify their markups.
"Peddlers"Guys, perhaps you are spoiled over there, in US. In the sense that it's a more open market, with a lot of competition, also more transparency maybe.
Maybe you don't know how it is here in Canada. In my perception, everything is opaque, with huge markup prices, lack of real interest from contractors for doing a good job but instead getting it as cheap as they can, but with big profits for them. They do not even have patience in designing intelligently a pipe route in the house etc. Only the commercial projects look great, for the residential customers it's just a quick money scheme. Again MY impression only.
If those contractors (which I HAVE contacted - three of them) were offering more reasonable prices for my (small) job, I would've gladly gone with them. Would you like to know how much did they ask for a job involving Vitodens 100 only, no indoor temp feedback, one zone, pex pipes, no LLH, no high-eff/ECM pump and 11 under-dimensioned pesky radiators?? They have asked me twenty-five thousand dollars, plus 13% sales tax. Do you consider that reasonable? When I could do the same with my father maybe for around 10k$, and with better equipment such as the Lochinvar WHN51 or the Vitodens 200 and with proper sized radiators!. Heck, they didn't even CARE to do a Manual-J calculation - they have said that they would assume any risk, and once I would sign the contract, the will do some calculations, and if there is less need for materials or rads (less than their ballpark estimate), I would NOT receive anything back as compensation. I had to buy the HVAC-Calc software license myself and the all the calculations solely.
Tell me, is that reasonable? And Chris, you are calling those folks from eComfort or pexsupply.com "peddlers". I am fully aware that they are just poor intermediaries - they sometimes are not even carrying anything in stock, but just facilitate the exchange of hands for the goods, and no manufacturer's warranties whatsoever. BUT, I see some values added by this companies, and I would really appreciate if such model could spread out more. Let me explain why: because they add PRICE TRANSPARENCY in the eco-system. In aca-nada we lack transparency and competitive markets completely. Heck, I feel myself like living in a feudal state (which doesn't even have a president, but only a prime minister). In other countries, US included, you can get into brick&mortar plumbing+hydronics stores almost at each foot step. You can actually go in and put your hand on a boiler etc...Here in Canada there is no such thing (at least couldn't find that yet). To me, the very fact that a store like ecomfort.com exists, and it can also help with the shipping and requires only some minor effort on my part (i.e. dealing with customs and brokerage), is a balloon of oxygen.
I know it's not the ideal model - again, if the contractors would be more reasonable and down-to-earth and not greedy for money, this situation wouldn't have happened. I always appreciate hardwork and giving proper compensation for a work done well. But for these Canadian leeches, I have only bad words to say about them.
And yes, consider me a "Internet peddler" - I won't be upset. At least, as Gordon admitted, the Internet has contributed to many good things, and favouring rapid exchange of information. Destroying the opacity - I know that lawyers, doctors, and other jobs of trades, HATE this transparency, because it gives people more power and freedom in understanding things and taking more opinionated decisions.
And, after all, I came to this web site because it is called ... HEATING HELP...It was not called "help for the heating PROs", right? Why do you have to be so arrogant, Chris? If it's one attitude that I don't like in general, it is the arrogance.
To me, living in Canada, each day, is a lesson of trying to humble myself even more. Is it good, or bad, don't know. But I hate arrogance.
Maybe you were trying to explain things in a certain way, in a more subtle manner, and between you, that looks like an intelligent/meanigful answer. Maybe I'm not smart enough to understand your subtleties. Or maybe you are trying to defend a sort of mainstream idea for Vitodens.
But when I try to ask something very bluntly, such as "can Vitodens 200 control a system pump" and not only during "warm weather regime", or what vitotrol 300 really does, you are always trying to answer very indirectly, such as "go get the Knight instead", never admitting black on white that Vitodens 200 was thought for a certain use case - constant circulation.
Mr. Eastman's last post - it was more than welcome, sounded like dis-interested and very helpful answer. I really appreciated it - thanks to him I understand now. Also, Gordon's help was more than welcome.
I was not trying to get a 'design for free'. As Gordon said it, just trying to have a better understanding of the stuff first. I am an analytical person in principle, sometimes even too much. Eastman explained very black and white, finally, why the LLH or other form of separation is quite a must with these Viessmann models. And that there may be other companies/models which do not have this restrictions (initially I thought it's rather something like a 'safety measure' like a 'just in case' factor from Viessmann).
I also understand NOW, why back in Europe, you cannot find Viessmann 200 models being sold with powers less than 45kWatt. It's because only for models higher than that, they require the presence of the LLH, otherwise the warranty is not honoured. And since people over there don't like to use it, the sellers simply decided not to put lower models on the market. For lower powers, they will sell only combi models.This post was edited by an admin on April 10, 2013 8:26 PM.
My LimitsGordan. My limits on Viessmann go beyond what is in the manual. In the political correctness I won't get into how many and who this OP has called to try and buy the boiler from. I understand the internet and deal with it every day. I agree, we all share and give our help. Should it go to the point where we give the inside information on the product to take a job away from contractors such as you?
I still believe in protecting the trade contractor and when it comes to Viessmann, because of it's limited distribution and limited trade understanding, it's one of the last boiler lines the consumer has yet to be able to tap into from a functionality and control standpoint. I don't mind helping an end user after an install and go the full Monty but in the non installation phase your right. Not comfortable with giving the key to the city.
on/off and indoor feedbackSmihaila, your experience in Europe with hydronic heating is probably not comparable to a system using indoor feedback. Indoor feedback systems are a major step up from central on/off thermostats. They are still quite rare and I think it is unlikely you would have any direct experience or spoken with someone that had such a system. Most indoor feedback systems are very precise. Much more than an on/off thermostat. They also tend to be much more sophisticated. I would be quite surprised if the Vitodens could not manage its firing cycle correctly during any part of the season.
Your concerns are valid though, and many European systems may indeed benefit from the addition of an on/off thermostat, but an indoor feedback system would be even better.
In a nutshell: electronic dynamic ODR + indoor feedback thermostat is much better than user adjusted ODR + regular on/off thermostat.
Let me clear up some issues:
"The only "oddity" is the fact that, during the fire-off period, the pump
will always work, instead of, let's say, working only 3-4 more minutes
since the moment of time the boiler ceased firing. Because what purpose
serves to recirc water which in the meantime gave up all its heat energy
into the rad circuit and now it's cold? That's how I remember it
working back in my former apartment anyway."
I can't speak for the Vitodens, but pump settings are almost always configurable. You can set it to run constantly, turn off right away, or run for a little bit of time after the flame cuts off. Keep in mind that the electrical consumption of a modern single pump residential system is extremely low --probably less than the boiler's electrical power requirements. *But* In most systems it is *not* advisable to install the Vitodens without an LLH. This boiler uses a water tube HX that has quite a bit of hydraulic resistance. It is quite likely that you will have to use some type of P/S arrangement.
"So, shall I understand that there won't be any situation whereas the
outdoor temp is still considerably below desired target indoor temp, and
the boiler will be impossible to be in "turned off" state eventually?
This would mean the following: If it can maintain a firing rate even in
VERY LOW modulation conditions and thus it burns the optimal volume of
gas, even in such extreme conditions, then my hat off !
The Vitodens can barely modulate low enough for your project. This is a major concern because modulation is arguably the key to making all of the other features of this boiler work as intended. The boiler would be forced to toggle on and off for the majority of the season, despite its sophisticated feedback control system. It would perform well "on the average," but a system that could modulate much lower is desirable. Keep in mind that the goal really is to keep the burner on as long as possible. Matching supply with demand on a continuing real time basis is the ideal, both for efficiency and occupant comfort.
"It's funny, because they say that they are happy sometimes with the
boiler firing less often but working for longer. Maybe they are
referring to the warm temp case (spring or autumn). Otherwise it doesn't
make sense, unless there is something wrong with their boilers and
can't modulate low enough and waste small fuel volume."
Their boilers can not modulate low enough. In this situation an indoor feedback system should provide identical (if not better) fire cycle management.This post was edited by an admin on April 9, 2013 10:36 PM.
ClearDear Eastman, thank you, thank you and thank you ten times. For clarifying more on these ODR and modulation aspects. I was hoping that by going with the lowest Vitodens 200 model, the boiler would be able to modulate reasonably and no short-cycling. With or without a LLH. You are a 2nd source confirming that the WB2B-19 may not be appropriate for my need. It's funny though, how come ALL of those three local contractors (reputable companies, I can give names!), they have recommended the Vitodens 100 model (the one going up to 97 kBTU). Even if one of those 3 was somehow able to have an ballpark estimate for the heat load.
I understand now - that maybe I'm too anal about the "boundary/extreme conditions" as far as the ODR is concerned. And, with a properly sized boiler, the boiler should be able to modulate down (i.e. burn the gas at moderate volume) even when the outdoor temps are starting to get close to the indoor.
And you are right about the "feedback" that I have got from those people in Europe, about their "conclusion" about the on/off thermostat bringing cost savings down. Indeed, their boilers may be cheaper (Central and Eastern Europe usually goes with lower-end models - people can't afford something expensive, and there is an invasion of OEM products, made in Turkey or other less than ideal countries etc). So, their boiler may not be able to modulate down enough, with "finese".
It's funny a bit - when I have started this project, I wanted to go for the ODR idea, definitely. Because I knew how the other, "normal american" system is and wished to stay away from that. But somehow, in the middle of the road, I got sidetracked by other more recent opinions from other persons. And since nowadays Europe tends to do stuff like in Americas and Americas vice-versa (i.e. I gave the example with America switching from copper to pex, while Europe is doing it opposite), somehow I thought that those guys and their thermostats are on to something. But now I understand.
Eastman, the only thing that may come to a bit of surprise to you is that the assumption about "I can't speak for the Vitodens, but pump settings are almost always configurable. You can set it to run constantly, turn off right away, or or run for a little bit of time after the flame cuts off" - doesn't seem to stand true for WB2B and its power/pump module. The way I understood it (always indirectly!) was that only for the boiler pump, not the system pump is capable of that, and that only if a LLH+immersed temp sensor is installed.
And yes, if we go with an ECM type of pump, the power consumption would be quite reasonable, even with the pump always on or with the speed reduced (as in case of a Delta-P or Delta-T pump - too bad that we can't get the Bumblebee yet).
Thanks again for the logical and direct explanation.
All in all, I find it extremely strange that the Viessmann folks didn't make a 200 boiler model available, to suite even lower loads, like mine (35-40 KBTU). My forced air furnace (16-year old, a "Heil") is sized for 50 KBTU. I don't understand why the contractors strives roughly for the double of the real max heat load. Is that a sort of magic formula, which applies only to forced air?
Statistically...most systems are twice the size they need to be. This wouldn't be a problem if they could modulate all the way down to 0. But most systems can only drop to a minimum of 20% of full fire --a 5:1 ratio is very common in North America for hot water boilers. I actually think the modulation ratio may be worse in Europe due to stricter emissions requirements --something more like 3 to 1 for residential equipment. (Someone correct me if I'm wrong.)
Chris suggested the WHN 55. This has a minimum mod. of 11,000 btus. (I know you're a kilowatt man but I just can't do it.) There are models that can go slightly lower, but the WHN 55 is probably more forgiving of DIY mistakes due to its firetube HX. A P/S arrangement is recommended but not really necessary if you do your homework. It does not come with indoor feedback though.
I'll trysourcing the WH055 first, preferably locally. And if I can't find it I'll have to go with the WB2B-19 and LLH. In that latter case, maybe I'll have to add a rad even in the un-heated garage (which is empty without a car LOL), just to increase the heat lot and avoid using that buffer which Chris was mentioning about.
About the modulation ratios, I recall someone posting something about an interesting boiler model (IBC), which was able to achieve unusually high X:1 modulation converstion ratios - possibly due to more "liberal" testing and assessment procedures.
I have found a Lochinvar local representative, and he was a bit puzzled as to how for a 1800sqft house (of which 500sqft is the basement) such small model is needed (39,000 BTU) :-). He was asking for room measurements / I have sent him my hvac-calc figures and we start from there.
smihaliaAdding rads in the garage is like filling your soup bowl all the way up even if you are not hungry. At a fundamental level, any boiler that can not modulate below your maximum heat loss is a poor choice. One could argue that you should just get a fixed output model then. Surely there are other options that you have access to?
You mentioned you have a 50,000btu furnace. Is there something wrong with the current system?
The forced air furnaceIs 16 years old (which is also the age of the house). It's burning about 270 cubic meters/month during high peak winter season. The electric blower is drawing 800watts/hour. And there is no comfort at all. The furnace doesn't fire too often and after firing, it gets cold in the house quickly. The Honeywell 'programmable thermostat' is set for 23 celsius, and sometimes it doesn't seem to register the right temperature. When I feel too cold in the house, I just have to raise the thermostat manually from 23 to 25, just to make it send a heat demand. And then I move it back to 23 (and will still run). Just to have the stuff working.
I tried the best I could to increase the comfort - installed R-50 sprayed polyurethane close cell insulation in the attic, installed a steel roof, replaced all the windows with European tilt-and-turn windows, triple glazing, Trocal uPVC 70mm profile, low-e, argon, Uw at about 1.0-1.2 K/m2. Everything with hard earned cash, no credit.
And still cold. Most part of the "hot air" gets lost on the route from the basement to mainfloor. The air just raises up and stays close to the ceiling. Also the master bederoom is facing North and situated above the garage. The garage has no proper insulation for the outside walls, also for the part of the ceiling that gets outside the house. Also, the air duct that comes to the master bedroom, crosses all the length of the garage. Go figure.
I hate the forced air systems with passion :-)This post was edited by an admin on April 11, 2013 7:00 PM.
Have you investigated...variable speed furnaces? I believe there are models that can modulate both the flame and blower. These units are also quite amicable to various zoning systems and are capable of achieving much more precise temperature control. Such an upgrade would almost certainly be less than installing an entirely new system.
Well, sure...When you're externally turning off the boiler for a period of time, in essence you're using the thermal mass of your home as a buffer. The only benefit of this that I can see would be to, in essence, lengthen the firing cycles, but there's a catch. The boiler does not directly heat the space; it heats the water that heats the space. So, not only does your average water temperature have to be high enough to cause overheating, which would then trip the thermostat into shutting off heat demand, but it actually has to be high enough to cause the emitters to shed enough heat into the space to equal the minimal burner modulation of the boiler. Otherwise, the boiler will still cycle its burner as the water temperature will of necessity exceed the setpoint.
I still think you're not getting the basic idea behind burner cycling. The ODR just determines the water temperature setpoint. Call this the "floating" setpoint, whereas non-ODR boilers have a "fixed" setpoint (whether the control is a simple aquastat or a more sophisticated PID-type control.) The boiler will circulate as long as there's demand for heat (from a thermostat or other control, or constant.) The boiler will FIRE until supply temp reaches setpoint + differential. Then the boiler will shut off the burner until supply temp reaches setpoint - differential. The reason there is still circulation is because there is still useful heat in the water - it is maintained at a setpoint. Below minimum modulation, EVERY boiler is just an on-off boiler.
Now the basic question becomes: does the loss of efficiency that comes from higher average supply (and return) temperatures outweigh the loss of efficiency that comes from the boiler cycling its burner for shorter intervals? My hunch is that there's some sort of break-even point, depending on the system. It could very well be, however, that the differences would be minuscule.
Indeed"When you're externally turning off the boiler for a period of time, in essence you're using the thermal mass of your home as a buffer. The only benefit of this that I can see would be to, in essence, lengthen the firing cycles, but there's a catch. The boiler does not directly heat the space; it heats the water that heats the space. So, not only does your average water temperature have to be high enough to cause overheating, which would then trip the thermostat into shutting off heat demand, but it actually has to be high enough to cause the emitters to shed enough heat into the space to equal the minimal burner modulation of the boiler. Otherwise, the boiler will still cycle its burner as the water temperature will of necessity exceed the setpoint. "
Exactly, it is as if those people reporting on those strange experiments, and shutting the boiler for long periods, combined also with long re-fire periods, were getting into a 'sweet spot' situation - making the boiler modulate stronger but - paradoxically - with less total fuel per day than in the other case. Indeed, maybe when they do that, they create a proper matching between the modulation capability of the boiler and the house heat demand.
It is as if they mistakenly install way too powerful boilers (which is not un-realistic, because not too many over there do proper heat load estimates and also the types of house constructions over there are very diverse i.e. concrete, brick/mortar, also there are many flats/apartments as opposed to detached houses). And by letting such powerful boxes (i.e. 26kW or even 35kW) run in "odr" mode, they will shortcycle and each startup will obviously ask for more gas to be burned temporarily.
These boilers are easily accessible over there. Many people are even learning and installing themselves. At about each 1-2 kilometers, it's impossible not to find at least one HVAC specialized store, where you can actually touch and buy directly. Not via accountants and price quotes and 2-3 weeks orders. Everything is right in front of your eyes. You go to a store like homedepot (or even smaller), you grab the device in your car and off you go :-)
Mind you, we shouldn't go into the other extreme, as it seems to happen here: where everything is ultra-'regulated' and ultra-cautious and the business doesn't move, if you know what I mean. Too bad that there isn't too much demand for hydronic systems here, to make the market more diverse.
Thanks for clarifying.
DIYI feel quite humiliated while reading all this mess. We have here DIY fer who decided that plumbers are charging too much for their knowledge and expertise and years of experience and decided that build heating system is not a big deal. Just buy boiler and install few pipes. Meanwhile lets ask some quick questions on this and I m sure some other forums. Then do it. I installed heating systems at houses belonging to heads of major corporations, banks and also people who I know probably hardly even could afford these systems as well. And all of them showed respect to what we did. Rarely I see such luck of respect as in this tread. What would mr. Michaila say I I would start developping software when i need one? Would he go same distance as was done here. Just my 2 cents.This post was edited by an admin on April 14, 2013 8:20 PM.
PrecisileyWhy I walked away from this thread. Especially knowing he's contacted everyone under the sun to get the boiler as cheap as he can.
Not trueGennady, I have never said that it will be me (the software guy) doing the install. It will be my father, who's been doing more than 30 basic installs like this one. Please stay close to truth and don't be arrogant. You say that you did this and that, but honestly you still didn't seem to know how the PMP module in vitotronic 200 works :-).
And to answer Chris' last message, if buying something through an online store, or asking a few things on how the Viessmann 200 works (or the ODR principle in general), is considered 'being cheap' (as opposed to attempting to contract the whole install via a local company) and trying to put at good use my father's skills (while trying to see what other differences are involved in general with the North-American ways of doing installs), yes, it's 'cheap'.
Look, I appreciate everyone's input. The project is in 'go' status - the rads are about to come in one week. And the boiler - we're waiting for quotes for both the Knight and the Viessmann. I'll keep you guys posted with some pictures (if you are interested) with the install.
Ok, you lost meYou've come here to learn about heating systems, but honestly, it seems to me that you should learn a bit about grace, too. To come somewhere with your hat in hand and then lash out at people who have provided valuable information to you (albeit apparently not as much and not as quickly as you feel you're entitled to) is bad form. My impression is that Gennady, for one, has forgotten more about what you came here to ask about than you'll ever know, or care to know. I did not feel that there was anything wrong with you asking questions or even doing this project yourself if you felt up to it, but I am taken aback at the argumentative attitude. Please stop it. You're here asking for favors, so act like it.
RespectI agree, I'm asking for favours, true. I may be impatient and stressed out. It's just that I feel frustrated that questions that seemed plain English, simple, are not getting a direct answer (i.e. how vitotronic 200 is driving the system pump).
I wasn't trying to 'steal' any secrets of the trade - I thought that for you guys, installing Viessmanns is a daily bread and the things which were unclear for me = to you were very simple things to answer. Look, I'll print all the docs (as opposed to reading from screen) and read again all of them. Maybe I wasn't paying attention enough, and read it superficially. If that's the case, then my sincere apologies.
Also, Chris was implying that I am trying to "short-circuit" trades men and their jobs...By going via Internet sellers etc. I mentioned about that only as a fall-back strategy. Because obviously it's less than ideal not to see the merchandise, to have to deal with forex conversion, brokerage/custom/duties and unforeseen situations. That is why, as a matter of fact, I am already buying the first batch of goods - the radiators - via a local company - which happens to be the main wholeseller for Canada.
Now I am waiting for quotes for Viessmann and Lochinvar, pumps, copper piping etc. Also from a local warehouse - I consider myself fortunate enough (besides having the opportunity of getting professional opinions from you) to know a guy who has an account with two providers named Noble and Desco. Desco is the main Lochinvar distributor. I hope that I can get the stuff from them.
For the manifolds, perhaps my father will just make them himself - or I'll try to convince him to buy them pre-fabricated. He's a quite an old fashioned guy. Did a lot of plumbing work in his life - mainly for peoples' house but also for some institutions such as schools or kindergardens. His father (my grandfather) was seen as the most crafty guy in his village. A jack of all trades - lots of people in the village were coming to him to fix lots of things: from cars, agricultural combines, to cuckoo clocks and doing even masonry :-)This post was edited by an admin on April 15, 2013 10:18 PM.
I can understand all thatFeeling frustrated is one thing, how you express it and at whom you direct it is another. Often (perhaps most often?) the simple English language answer to a direct English language question is "it depends." And often our frustration comes from a nagging feeling that we've gotten ourselves in over our head - something I'm personally very familiar with. But it was your choice to open up Pandora's box (instead of your checkbook) so you really should only be frustrated at yourself. :-) The kind people here don't owe you their time, so any amount of it that they do choose to devote to answering your questions merits appreciation. Even if you don't get a direct answer, you'll usually get some kind of a pointer where you need to do more learning, and that's invaluable! Also, their concerns about do-it-yourselfers (or their jack-of-all-trade relatives) have a solid basis in what they have seen out there (though, truth be told, some of the more horrifying examples paraded here appear to have been the handiwork of 'tradesmen.') When you come off as impatient, you're signaling that you're lazy in your quest for knowledge (whether this is true or not) and that rubs folks who have spent decades learning what you seem to want to (but can't) learn in days, the wrong way, and confirms some of the perhaps uncharitable preconceptions they may have about do-it-yourselfers in general.
None of this is meant to discourage you from what you've set out to do, just to perhaps provide a point of view about how you currently seem to be going about it.
Here's My IssueYour not looking for basic operational information. Your looking for the information the tradesman uses to put food on his table for his family. With that gained information you then think you can now just go purchase the boiler from the net. If you were a stand up guy, you'd purchase the boiler from the industry of those that helped you or support the local tradesman not a website that swipes your card.
In my opinion you have been given basic operational information. Why should we feel obliged to give you more?This post was edited by an admin on April 15, 2013 2:57 PM.
Read the directions knucklehead200 and Vitotrol do everything your asking. Coding 2 - see Vitotrol influence factor and about 6 different system/boiler pump stop options. Thats all im tellin ya. When i used to ask how to use these unique features i got the keep it simple stupid. Had to figure it out myself. I have installed dozens of Vitotrols on single zone gravity or forced retrofits. If you install a Vitodens 200 its the cheapest communicating t-stat on the market! NA may be getting the better modulation of the UK Vitodens along with the new Vitotronic control this summer. Now go hire a professional.
ThanksAbout coding 2 and " 6 different system/boiler pump stop options. " -- maybe I haven't read carefully enough the service manual - but everything there about system pump stop options was either related to mixing valve operations or when the 143 "external demand"/"external blocking" options are being used.
If what you say is true, and coding level 2 will be able to configure the system pump to stop when no mixing valve or plug 143 is used, then it will be excellent.
Vitotronic 200 Service InstructionsBurried inside the vast number of docs that are made available via the viessmann.ca web site, I have found a very interesting document, named Vitotronic_200_si.pdf. Which is applicable to Vitotronic 200 model KW2 (part number Z001 230). Also, very strange, the doc is not searcheable. I've spent some time last evening to ready it carefully. Considering the level of info that is there, I'm now beginning to understand why the shroud of "fuzzyness" and mystery from Viessmann. It seems to give some hints about certain algorithms and compensatory/adaptive types of controls.
First of all, I'm not sure whether this is applicable to the Vitotronic 200 module that comes by default with WB2B models (i.e. called "HO1").
Here's the the info that I consider paramount - perhaps you could help me in understanding a few things from the list below:
-Page 18: "The heating curve can be adjusted along the desired room temperature axis, resulting in a change of the on/off switching behavior of the heating circuit pumps (HCP), if the heating circuit pump logic function is activated (factory default setting)."
=>ok, when I saw the "pump logic function" being mentioned it stirred my interest. But further on I understood that it's more about warm weather shutdown stuff, freeze prevention and other auxiliary things. Read on.
-Page 47: "Heating Circuit Control: The desired supply temperature value of each heating circuit is determined by the outdoor temperature, the desired room temperature, the operating mode and the heating curve."
=>Note: "the desired room temp" does not necessary imply the presence of a room sensor/Vitotrol. But we'll see where that comes into the picture. Initially I got a bit disappointed when reading at page 76 about vitotrols, but then I realized something new. Read on.
"The supply temperature of the heating circuit without mixing valve corresponds to the boiler water temperature. The heating circuit without mixing valve is dependent on the boiler water temperature and its control range limits. The heating circuit pump is the only control element.
Room temperature: In conjunction with room temperature dependent control: Compared with the outdoor temperature, the room temperature has greater influence on the desired boiler water temperature. The magnitude of this influence can be changed via coding address "b2". (see page 94)."
=>Now, we need to understand what the room temp means in this context. The "estimated" value or something delivered by an optional vitotrol?
Pag 48: "Summer energy saving function (heating circuit pump logic):"
=> now we begin to understand what the HPL really means. It's not a general logic, but more in conjunction with warm weather or start of summer season.
"If the outdoor temp is higher than the preset room temp setpoint value, the heating circuit pump is switched off and the desired supply temp value is set to 32F / 0 Celsius. The switching threshold can be individually selected via coding address "A5" (see page 93)."
Extended summer energy saving function: The heating circuit pump can be switched off:
-if the outdoor temp exceeds a value preselected via coding address "A6".
-if the desired room temp is reduced via coding address "A9". (see page 94) -- "Heating circuit pump logic function with change of setpoint / pump-off time"
-in conjunction with heating circuit with mixing valve ([...])"
=>This "A9" register seems to be very intriguing. Anyone caring to explain it a bit, and if it's available on the North-American WB2B models ? What is this "pump-off time"?
Pag 50: "Variable frost threshold. Coding "A3" (see page 93). Values between 0 and 15 set various range for pump to be on and off."
=>not super relevant to my quest :-)
"Summer energy saving function (heating circuit pump logic function, outdoor temperature-dependent). Coding address "A5" (see page 93). Value=5 (default) means With heating circuit pump logic function (HPL). The heating circuit pump is switched off when the outdoor temp (OT) risese by more than 1.8F / 1 grd Celsius above the desired room temperature (RTdes).
OT > RTdes + 1.8F (1grd celsius). Other values: 0=without heating circuit pump logic function (HPL function). Or other temp "edge" ranges via value=1...15"
=>again, not super-exhilarating.
Pag 51: Heating circuit pump logic function with change of setpoint. Coding address "A9" (see page 94). Value=0 (default) means without pump off time. Value=1...15 means WITH pump off time, which means Heating circuit pump logic function with change of setpoint (through change of operating mode or changes on "sun temp" selector knob or the "moon temp" button."
=>tries to give more details, but still fuzzy.
Page 76: "Vitotrol 200: The remote control has a built-in room temperature sensor for room temperature-dependent control in conjunction with a heating circuit WITH MIXING VALVE."
Page 77: Vitotrol 300: same statement as for Vitotrol 200.
=>When I've read that I was very disappointed. But you have to be very careful on how you read it. It tries to imply that a direct influence of the target/setpoint temp can be exercised only via a circuit with a mixing valve. And without mixing valve, there will be some "heurisitics" (and unclear if the room temp senzor is an input for these "heuristics")
Page 82: "Components (continued): Input extension module 0-10V:
To default an additional set boiler temp via a 0 to 10V input in the range 10 to 100 grd Celsius / 50 to 212 F or 30 to 120 grd celsius / 86 to 248 .
To signal reduced mode and regulate a heating circuit pump to a lower speed.
-Plug 144: 0 to 10V input
-Plug 145: KM BUS to control unit
-Plug 157: Zero volt contact
See DIP switch marked as "B", with 4 switches. Can be set as follows:
Dip switch 1 = on => reduced mode - Heating circuit A1.
Dip switch 4 = on => set value default 10 to 100 grd celsius.
Dip switch 4 = off => set value default 30 to 120 grd celsius.
Note: out of switches 1 to 3, only ONE switch can be set to ON."
=>Unclear what this "reduced mode" means. Also seems to imply that it works in conjunction to a var speed pump. Is such control available for American models?
Page 92: Coding level 2, address "9d". Value = 0 (default) means without input extension module 0-10V. Value=1 means with input extension module (recognized automatically)"
=>Seems to control what page 82 said.
"A0:0 Boiler circuit/mixing valve circuit without remote control. Value=2 means with vitotrol 300 remote control."
Page 93: "coding level 2, address "A3". Value=2 means The heating circuit pump is switched on at outdooor temps BELOW 34F/1grd celsius. The heating circuit pumps is switched off at outdoor temps ABOVE 37F/3 grd celsius."
=>Seems related to warm weather shutdown regime. Not very "dynamic".
"Coding level 2, address "A5". Value=5 (default) means With the heating circuit pump logic function (HPL function), the heating circuit pump is switched off when the outdoor temp (OT) rises 1 grd celsius above the desired room temp (RTdes). Other values = 1...15 will set different "edges" for the OT to RTdes relationship."
=>Again, seems related to warm weather shutdown regime.
"Coding level 2 address "A6". Value=36 (default) means Automatic switching from normal heating to summer operation NOT active. Other values = 5 to 35. Means automatic switching from normal heating to summer operations at a variable setting value from 41 to 97F (5 to 35 grd celsius) plus 1F/1grd celsius at which the burner and heating circuit pump are switched off and the mixing valve is closed."
=>Again, summer time related.
Page 94. Coding level 2 address "A9". Value=0 means Without pump off time. Value = 1..15 means with Pump off time: Heating circuit logic function with change of setpoint (through changing the operating moder or changes on the "sun temp" selector knob or the "moon temp" button."
=>This is the most detailed info that can be revealed about the "A9" register. Again, I appreciate if someone could enlighen us more on this? Seems to be something essential.
"Coding level 2 address "b0". Value=0 (default) means Weather-responsive operation in normal heating mode and reduced operation. Value=1 means "In conjunction with remote control: weather-responsive operation in normal heating mode and with room temperature depedent control for reduced operation". Value=2 means "In conjunction with remote control: room temperature dependent control for normal heating mode and weather-responsive operation for reduced operation". Value = 3 means "In conjunction with remote control: Room temperature dependent control for normal heating mode and for reduced operation".
=>Not sure what weather-responsive operation means.
"Coding level 2 address "b2". Value=8 means Room influence factor = 8 - in conjunction with remote control and operation with room influence coded for the heating circuit. Value=0 means "without room influence". Value =1..31 means "room influence factor adjustable from 1 to 31".
=>Unsure if this involves the presence of a Vitotrol or it can work without it (some inference/Artificial intellifgence/Anticipative algorithms?)
"Coding level 2 address "b3". Value=0 (default), means "Basic value: 127F / 53 grd celsius. In conjunction with the remote control and for the heating circ operation with room temperature control must be coded". Value = 1 means "Basic value: 100F / 38 grd celsius"."
Page 95: Coding level 2 address "b5": Value = 0 means "no room temperature controlled heating circuit pump logic function. Value=1 means "In conjunction with remote control: Heating circuit pump OFF if actual room temp (RTact) is 5.4F / 3grd celsius higher than desired room temp (RTdes). And Heating circuit pump On if actual room temp (RTact) is 1.8 F / 1 grd celsius HIGHER than desired room temp (RTdes)"
=>This seems interesting. Also the fact that Viessmann always seems to insist on using the "remote control" denomination for Vitotrols. Question: isn't there a typo? In both on/off cases, the RTact has to be higher than RTdes. Only the edge differs? Seems illogical.
"Coding address "b6". Value=0 means without boost heating/rapid setback. Value=1 means in conunction with remote control: with boost heating/rapid setback."
=>Boost/rapid setback: no idea what's supposed to mean. Something like a fast warming/cool down when you come home after a long time/vacation? Or party mode?
Page 96: address "b7": in conjunction with remote control in room sensing mode: without optimized switch-on time or with optimized switch-on time.
b9: Without or with learning optimized switch-on time.
C0: idem to b9, but in conjunction to remote control.
C1: values for C0 for the time shift.
C2: with/without learning optimized switch-off time.
C8: Without limit on room influence (value = 31) or 1...30 means "in conjunction with remote control: limit on room influence variable from 1.8 to 54F / 1 to 30 grd celsius."
=>C8 seems to state, for the 1st time, that the Vitotrol seems to have a certain influence in the indoor temp estimates and that Vitotronic 200 will consider within its internal algos that input. In what manner - it's mysterious.
=>Also, what "switch-off time" may mean?
"E5: With or withour variable speed heating circuit pump. Value=1 (non-default) means "with" (recognized automatically)
E6: max speed of variable speed pump.
E7: min speed of variable speed pump
E8 and E9: again speed control for var speed pump."
=>The E5,6,7,8 and 9 registers seem to be dedicated to controlling a var speed pump. Is such pump available in North-America? And where do you plug it in?
Page 100: "the heating circ pumps are switched off before the desired room temp is reached. OR, the heaitng circ pump for heating circ 1 or heating circ 2 is switched off if the current room temp exceeds the desired room temp by 5.4F / 3grd celsius. The default settings is "the heating circ pumps are switched off in the heating program if the outdoor temp rises more than 1.8F/1 grd celsius above the desired room temp."
=>This page/paragraph tries to summarize what those options are really meant to control. Looks interesting.
And finally, a 2nd document about Vitotronic, titled "Vitotronic_200_TDM.pdf" says on Page 5: The installed sensor measures room temperature and, if necessary, takes corrective action and initiates fast heat-up at the outset of the heating operation (if coded).
Sounds interesting overall. The viessmann seems to be a little hidden gem, somehow (I personally feel) shrouded in some (intentional maybe) mystery as far as the control and internal logic are concerned.
I've also received the quotes for both WB2B-19 and WHN055, and the prices are pretty much the same. But for the Viessmann, you have to pay additionally for LLH, LLH immersion sensor, 2 Grundfos Alpha pumps (one set to fixed regime for the primary circuit and the other to variable Delta-P for secondary), plus concentric venting kit, plus vitotrol 300. For the pumps, let's say it's not a concern - because as opposed to WHN055's integrated pump (a UP15-55) I can install something more energy efficient/ECM.
If it were for WHN055, I'm not sure if an indoor control/sensor exists similar to vitotrol? I guess it counts only on a "on/off", classic thermostat (i.e can reuse what I have from the forced air furnace?).
My biggest concerns right now are:
1. That even with a LLH, Viessmann's high min. BTU load start limit (30kBTU) may be too high for my load? But where is that 5:1 "down modulation factor"? Shouldn't it be 67k divided by 5?
2. Lochinvar's warranty seems VERY FISHY to me. Looks like they have something to hide. Stuff like: "no warranty for parts which the boiler aggregates but not manufactured directly by Lochinvar", also "warranty starts from the manufacturing date indicated on the boiler unit, and not from purchase/install date" and that stuff also with pro-rated warranty. THIS SEEMS EXTREMELY FISHY.
Thank you and sorry for the long message.This post was edited by an admin on April 17, 2013 9:39 PM.
SmihailaWhy are you still considering the Vitodens? The specific model you are looking at can only modulate from 31 to 67 MBH. I thought your house required only a maximum of 30 to 35? Almost all of the features of concern are contingent on the boiler functioning in its modulation range.This post was edited by an admin on April 18, 2013 12:40 AM.
Was still considering itsimply because I am worried about the quality and reliability of the other alternative. It's true that somewhere, at its origins, the Lochinvar's design was inspired by some European model (Giannoni) and started building up/improving from there.
If many people are using Lochinvar wall hung models and haven't encountered major issues with them, I could go with it. Still, I was puzzled by the fact that the 5:1 modulation/conversion factor with the Vitodens somehow doesn't add up.
Eastman, would you say that the Knight is a damn good boiler? If you don't pipe a P/S with it, would it still be possible to use a variable speed pump, as long as you can guarantee that there will be 2-3 rads fully opened, permanently, to have a min flow assured? Lochinvar was stating that for a var speed design only a P/S circuit is recommended. I wished to have min electrical energy consumed - and even if those 0...10 VDC controlled pumps from Grundfos or Taco (VFD?) are not ECM, by being variable I suppose they will draw considerably less than a UP15-55 which is const speed? Or Alpha could be used, in delta-P, but without an interface/a way to tell the boiler what flow the pump is currently using.
GiannoniMany mod/cons used the Giannoni HX to get a product on the the North American market quickly while other designs were being developed. There is now quite a variety. The WHN055 uses a fairly unusual vertically oriented firetube hx that has received positive reviews. The Giannoni hxs are watertube. There are pros and cons with each style and many manufacturers offer product lines featuring more than one type of hx.
Where are you reading the 5 to 1 modulation for the Vitodens? This ratio is most likely for two units sequenced together. Don't they make a smaller model? What other manufactures do you have access to locally? Even the best engineered systems fail; having quick access to replacement parts and trained service reps should be considered.
How much do you pay for electricity?
Info-5:1 modulation for the Vitodens: I simply assumed that factor, because that's the factor that one usually observes with the mod/con boilers. And only IBC (so I heard) would be capabale of higher ratios?
-Vitodens 200 smaller model: it's the WB2B-19 (67kBTU max rated and opening around 31kBTU as you mentioned).
-Other local boiler manufacturers/suppliers: besides Viessmann and Lochinvar, I'm not aware of others. There are Triangle Tube Prestige models sold via globalindustrial.ca, and Rinnai boilers sold via ... amazon.ca. This is a hint that there may be some local suppliers available for those. Any personal opinion on Rinnai ones? (I already have a tankless/instant water heater from Rinnai). Having access to replacement parts and tech service reps is a good point.
-Electricity bills: $117 CAD for 2-month period. Let's say $55 per month. 385 kwatt per month. All computer and multimedia equipment turned off @ night, via power bar.
it's not 5 to 167 divided by 31 is about 2. Hence the modulation ratio is about 2 to 1. Another example: the WHN055 is 55 divided by 11. That corresponds to 5 to 1. The IBC is 150 divided by 15, so it is 10 to 1. But the significant number here is really the minimum btu output. If your project's requirements are always below the minimum, than the boiler will almost never have the opportunity to modulate. If that is the case, than why buy a modulating boiler? This is why I think it is really worth your time to search out other equipment that can hit lower minimum btu outputs. 10,000 is about the lowest I am aware of, but it wouldn't surprise me if there are smaller models.
Regarding pumps: It sounds like you pay about 14 cents per kwh. Most of the electrical savings results from eliminating unnecessary pumps. A modern ecm pump would likely use less than 30 dollars a month even if it ran every minute of the day continuously. I think the savings associated with variable speed technology may shave a little off that amount during the shoulder seasons, but even when throttled down, traditional variable speed pumps fair quite poor. In light of this, it's not really a big deal weather or not you are allowed to use a variable speed pump in a directly pumped configuration. (at least in terms of electrical savings)
You spoke with Lochinvar? What was their concern with variable speed?
Regarding the Rinnia: I have no opinion on the Rinnia, Loch, Vitodens, or anything else. I'm not a boiler guy --I'm more interested in the thermodynamics and the practical engineering compromises that manifest in projects that are typical on these forums. Having said that, I find the claimed advantages with the vertical firetube heat exchangers at least credible, and there have been real world positive reports posted on this website. The disadvantage is the extra water in the hx associated with the design. During the summer, domestic hot water production leaves behind unused energy after each firing cycle. This can be improved with post purge cycle but the loss is never completely eliminated. However, in a predominately cold climate, I would expect such a disadvantage to be outweighed by lower pumping requirements and possibly an improved maintenance schedule.
Another thing for you to contemplate: Many boilers can except control signals from more sophisticated ODR + indoor feedback controllers. Check out Tekmar --I believe they are Canadian. Another player is the the Honeywell Aquatrol system, but I find their documentation lacking. There are others too, but these are probably the most readily available and accessible. These controllers have some very impressive features, but it is hard to justify the extra cost for a small project.
Mod & pumps-Viessmann WB2B-19 mod factor: yes, it looks like 2:1 and was puzzled about it, as usually the mod boiler manufacturers strive for 3:1 or 4:1.
-Yeah, good point about the min BTU output. 31K it's almost at my upper heat loss/need range. So, it's not only the higher hydraulic resistance, but also this factor - making the Viessmann less ideal for my need. 10K on the other hand is great - about each of the 3 floors of the house can make such demand. And the WHN055 will also be in very low modulation range almost all the time, thus featuring a higher efficiency (this eff usually goes lower when you reach the max BTU output).
-Lochinvar: I have asked that question to the local engineer/sales representative. Waiting for an answer.
-Firetube design: it's a non-issue for me that it's at slight disadvantage for the DHW production purposes. As I won't use it for that. Thanks for confirming that somehow the feedbacks from the field are showing such design as passing with high marks.
-Lochinvar Knight reliability: I've heard that the wall hung models of Knight are a bit harder to do maintenance with, comparing to the floor standing models - hard for the technician to reach the parts. I am also concerned a bit about the fact that the electronics board (both high voltage and low voltage) are placed near the boiler cylinder itself, in the same compartment? And the concentric venting is not by default with Lochinvar and you have to use a "Y" type of connector, which practically needs more space/longer routes for a side wall venting?
-In terms of var speed vs fixed pump, I understand that in a "fixed non-ECM" pump vs "variable non-ECM" pump scenario, the latter won't bring significant power savings. Because the var non-ECM pumps are not highly efficient due to their electric design (triacs and no permanent magnets?). What about a fixed ECM pump (i.e. Grundfos Alpha 15-155 set to fixed mode) vs a var speed non-ECM pump? The fixed ECM one would still be better, right?
I think the only considerable advantage that a var speed non-ECM pump (i.e. one controlled by a 0..10VDC input signal) is not the power savings, but rather the fact that it helps the boiler to achieve the intended Delta-T (a feature which we would love to have with Viessmanns here - as Europe already has it) ? In other words, the boiler will be in more control, and adapt the external devices to its need, not the vice-versa.
Also, in a P/S circuit, it would be interesting what the benefit will be in Lochinvar's case, with the primary pump being variable (non-ECM) and driven by the boiler, and with the secondary pump a Delta-P pump which would come also with an output 0..10VDC interface - and its output would be read back by the boiler (the WHN055 has also a 0..10VDC input). But I wouldn't go with a P/S configuration just for the sake of having this dual signal interfacing, right ? :-)
So, which of the 4 following scenarios do you think would be the best with WHN055:
(1) heating circuit driven directly by the boiler, and boiler shipped with its standard Grundfos 15-58, fixed speed and non-ECM pump.
(2) still one pump/one circuit, but with a var speed Grundfos 0..10V DC var speed pump with the input driven by Lochinvar. (pump coming as standard with the boiler would be discarded/put away).
(3) still one pump/one circuit but with a Grunfoss Alpha 15-55 ECM pump, set to fixed speed.
(4) P/S circuit, with primary circuit having the var speed pump from case (2) and secondary circuit the Alpha pump from case (3), and unfortunately the North-American model of Alpha not being able to provide a 0..10VDC output signal back into Lochinvar.
-In terms of control features, I would be ok with the basic ODR functionality. As long as it allows you to select various curves. Btw, Lochinvar seems to show linear cuves (you just select those 4 parameters - outdoor low and high limit, and indoor low and high limits). You don't see those various non-linear pre-defined curve (coded by a numbers) as in Viessmann. Also, I'm happy that I can reuse my existing thermostat (and I could invest in a better one much later, i.e like this one made by Trane in cooperation with Honeywell:
But my concern about indoor feedback is: can I get something similar to the Vitotrol - something to communicate the real indoor temp back to the boiler, instead of just an on/off signal? Or, as long as I'll be using the on/off thermostat only as high temp limiter and define any (slight) setbacks only at the boiler control level and not the thermostat, I'll be fine?
ThanksThis post was edited by an admin on April 20, 2013 12:02 PM.
Min required flow ratesStupid question: when looking at a boiler manufacturer's specs, how can one figure out the min required flow rates?
For both Viessmann WB2B-19 and Lochinvar Knight WHN055, I was able to see the max (or typical) flow rates. As Chris had mentioned earlier in this thread, the WB2B-19 has 6.1 gpm. Also the Knight shows 5gpm. At a Delta-T of 20F, that is.
How do you infer the min. value? By looking at the typical value that is stated for the max. Delta-T which the boiler's controls can support? (i.e. 40F Rise 3.1gpm for Viessmann and 35F rise 3.0gpm for Knight?)
If that's the case, then when attempting to use the WHN055, for a heat load of 33kBTU, I would require 3-3.3gpm for Delta-T=20. Wouldn't that flow rate be too close to the min rate, and thus making the use of a direct connection (i.e. no P/S) dangerous?
Are youwondering if there is a minimum acceptable flow at minimum modulation?
YesExactly! I am concerned that my system flow (which is also boiler's flow) might get below a min required value from the manufacturer and the water may start vaporising inside the heat exchanger.
Btw, I've just finished going through this thread:
and boy, so much info to absorb. Chris had made a very interesting point about the usefulness of a LLH/P-S separation, from a different "angle" - that being to aim for higher delta-T in the boiler circ to increase condensation (lower return temps). And which would trigger low gpm and small pump sizing in boiler circ.
But on the other hand, you too made a very interesting point - how come a P/S circuit with dT = 40 in primary (180/140) is more efficient than a non-P/S circuit with dT=20 (160/140 supply/return temps)?
I intuitively feel that the best scenario for my case is still one circuit, and using only one pump, but "standard size" and ECM. With these 3 scenarios for that ECM pump:
(1) With a variable input interface, OR
(2) that ECM pump to provide an output interface back into the WHN055.
(3) Or a third case - a simpler ECM pump (bumblebee or Stratos or Alpha) and neither providing output nor input to/from the WHN electronic board (via that 0...10V DC).
The case #3 is easy. But how can we be sure that it won't get too low flow and panick the boiler? I guess you have to guarantee at least 9-11 kBTU all the time for that to happen?
Case #1 can be done with Wilo stratos - a special adapter can be purchased to provide analog 0...10VDC input into the pump. Grundfos alpha doesn't have such adapter - only the Magna has it and that's too big, plus the Magna works at 230V only.
Case #2 is hard to implement - couldn't find such interface (pumps providing an output signal that WHN is ready to read).
Also, in this var speed (boiler) pump mode, we know from the WHN manual that the boiler will attempt to implement a const Delta-T alg. But the params of this alg can't be found in the boiler's menus, so I guess it's not flexible (i.e. to tell it the nature of the emitters etc)...But at least the alg exists, and that's good.This post was edited by an admin on April 21, 2013 11:59 PM.
boiler minimumsI too wonder about minimum flow at minimum modulation in the context of variable speed pumping and suggest starting a new thread specifically on this topic to get some feedback from a broad range of installers. I would imagine that some designs may be susceptible to bubble accumulation at extremely low flows and the ultimate answer may vary from model to model. There may be issues with laminar flow film boiling, too. High deltas at modulation minimums isn't a very common condition and I'm not convinced this is acceptable.
You found the Wilo ecm pump that can take a control signal --does it require 230 volts? I hesitate to recommend a specific pumping strategy in a well balanced system without hydraulic separation. I really don't think there is a tremendous amount to be gained with the more sophisticated approaches in this circumstance, although personally I'd enjoy the experimentation. The 0-10v alpha output mentioned does not quite sound right in particular. I believe the 0-10v input on the boiler controls only the flame modulation. This would leave you with a system that only modulates on flow with no direct control over the water temperature. Does the manual discuss this arrangement in particular? Perhaps there are other settings that can be activated that I am not aware of. I can see where this would be useful but I don't know that I would want it to take the place of ODR temperature control. I'm also concerned, regardless of whether it has 0-10v output or not, that a delta P pump may be capable of modulating flow much faster than the burner response. I foresee circumstances related to zone flow changes in which a delta P would aggravate spikes in the delta T across the boiler.
A fixed speed or deltaT boiler controlled pump would be more likely to mitigate such problems, but perhaps it's really a non-issue and I'm just being over cautious.
Also, keep in mind that there is nothing preventing one from putting pumps in
parallel and series. The resulting pump curves may allow for small
piping that is quite useful in retrofit circumstances.
Regarding "something to communicate the real indoor temp back to the boiler." I wouldn't be too quick to give up on this feature. These systems use their own thermostats that report back to the controller. The controller takes in all the indoor and outdoor temperatures, the occupant requested temperatures, and computes a water temperature that is adjusted throughout the day, automatically correcting temperature errors as loads change. The boiler does not receive this information, it merely is modulated via 0-10volt to achieve the requested water temperature. (The controller has a water sensor and may even control the primary pump directly in addition to any downstream mix systems for multiple parallel indoor feed backs.) The Tekmar system in particular can even control staged or ratio based parrellel deliver of heat into the same zone if, for example, you had a slow response heated floor, medium response time radiators for stage 2, and rapid temperature control forced air for stage 3 all in the same room! I think the Honeywell system is more cost effective though.
Wilo StratosDoes indeed have a number of interface options, but I don't believe the Stratos ECO has any.
Unfortunately, like all other currently available ECM circs, the curves are not a great fit for the short boiler loops we usually employ.
ECM pumps, variable modulation and indoor feedback-Wilo ECM pump @ 110V: I was able to find only Stratos ECO 16F. Listed at [u][color=#0000ff]http://ecomfort.com/stratos-eco-16f-high-efficiency-circulating-pump-115v-1314.html[/color][/u]. And here there is an interface module for it, but unfortunately not something for the 0-10V inputs but for LONworks interfacing:
I have attached 2 PDFs detailing which IF modules are available. Now, as SWEI was hinting, it may be that we are out of luck with the ECO model in particular :-(
The Wilo_Pump_Control_Management.pdf doc seems to list only these types of modules for the ECO MHIE model (whatever MHIE means?): Modbus, BacNet, CAN, LON, PLR. I don't know what CAN and PLR mean. Maybe some protocols?
The 26-Stratos_Interface_Module_0803.pdf doc shows on page 2 (section 3.2 - Function), that only the following IF modules support 0-10V inputs: "Ext Off", "Ext Min" and "SBM". Page 3 Fig. 4.2, 4.3 and 4.4 show the terminals.
Now I'm not sure anymore that ECO can accept such interface, and even if it can, I guess it will be hard to find one?
-Regarding the WHN055 0-10V input signal, to be clear, there are 2 0-10V inputs. One is labeled "BMS IN" and it's used by an external "Building Management System" and we aren't referring to that one.
The 2nd one is "SYS PUMP IN" and the Installation manual located at [u][color=#0000ff]http://lochinvar.com/_linefiles/WH-I-O-Rev%20K.pdf[/color][/u] states this on Page 53:
"Variable speed system pump: If a variable speed pump is used in the primary loop, and a 0-10V signal is available from the pump speed control, this signal can be used by the SMART SYSTEM control to anticipate changes in the building heat load. By connecting this 0 - 10V signal to the 0 - 10V SYS PUMP IN terminals, the boiler (or cascade) can modulate up and down as the primary flow increases and decreases."
Now, it's a bit unclear what modulation as term refers to in general. Modulation only for the fire, or other things. But, even if it were for the fire (as you said), wouldn't that corelate to proportional water temps as well? Otherwise, wouldn't that input be identical to the "BMS IN", or Plug 144 from Viessmann Vitotronic 200 ("external 0-10V signal" for dictating boiler modulation)?
First of all I don't get it - why it speaks about a primary loop?? Initially I thought it's a typo. But it insists and repeats the same term at the end of that section. Maybe it's referring to a multi-boiler / LLH setup, where the primary loop as concept is extended to be the loop to which all the cascaded boilers are connecting?
Or maybe that signal input cannot be synthesized by any existing pump (no matter how smart and/or ECM it is) - but IN FACT that's a more complex signal, which the BMS/external management system is generating (variable frequency driver)??
It's too bad that Lochinvar does not give examples of such pumps (featuring outputs instead of inputs). The only thing exemplified in the manual is the var speed (aka variable voltage) pump. They give 2 examples: Grundfos UPS 26-96FC/VS and Taco TACO 0013 IFC VS.
Also, Page 72 of the same manual, states:
"C (Operational Information): SYS PUMP INPUT: The speed signal received from a variable speed system pump control."
The other doc, service manual ([u][color=#0000ff]http://lochinvar.com/_linefiles/WH-SER%20Rev%20G.pdf[/color][/u]) mentions absolutely nothing about any configurations or more explanations about this input. It's saying only about the BAS 0-10V input signal a lot of things. And about the 0-10V variable output for driving a var speed pump in const Delta-T mode (see Page 26: "Boiler Pump Minimum Voltage: The speed of the boiler pump can be controlled by the SMART SYSTEM control in order to maintain a minimum dT through the heat exchanger. Thus, as the firing rate decreases, the speed of the boiler pump can decrease as well. The SMART SYSTEM control outputs a 0 - 10V signal to the boiler pump to control its speed. The Boiler Pump Minimum Voltage parameter determines the minimum voltage given to the boiler pump, thereby setting its minimum speed. The range of this setting is 2.5V to 10V. The default setting is 3.5V."
Btw, the service manual is quite interesting, because it mentions that the BAS 0..10V input plug can be configured in two ways: to mean a firing rate (a Power percentage) or a setpoint value (see same Page 26, section "BMS Type"). It is a hint that you may be able to connect there not a true, full-fledged BMS, but a smarter thermostat, which would be able to shift the ODR heat curve up and down, that is, something similar to Vitotrol 300?
-"I don't know that I would want it to take the place of ODR temperature control."
It's still unclear if "SYS PUMP IN" is like an "external demand for modulation" (as the BAS in terminal seems to do or Viessmann #145). Maybe the ODR-driven control is still not bypassed?
-"A fixed speed or deltaT boiler controlled pump would be more likely to mitigate such [...flow spikes from Delta-P pumps...] problems, but perhaps it's really a non-issue and I'm just being over cautious."
Interesting, so at least we know that by using a var speed pump (ECM or not, but ECM would still be preferable) connected to the 0..10VDC boiler output, it will be beneficial, acting like a const Delta-T pump. Now the question is: would the Lochinvar's internal control be more flexible/capable than a Taco VFD pump (non-ECM) or even than a Bumblebee? In the sense that it not only counts on the internally attached "inlet boiler temp" and "system supply" temp sensors, but it may know other things, which a Taco Delta-T pump cannot know?
The other question about variable voltage-driven pumps that are non-ECM: aren't they more prone to failures and rotor vibrations at low speeds? Making them noisy and shorter lifetime? That's the reason for seeking an ECM.
Maybe I could use a Magna if I can make 230V in my house? For that one an interface input module can be found for sure. But wouldn't that pump be too big for the job? :-)
-"Also, keep in mind that there is nothing preventing one from putting pumps in
parallel and series. The resulting pump curves may allow for small
piping that is quite useful in retrofit circumstances." Could you please elaborate on that? Are you thinking about scenarios where standard pumps cannot accommodate the head/flow and more power would be needed?
-"Regarding 'something to communicate the real indoor temp back to the boiler.' I wouldn't be too quick to give up on this feature. [...] The boiler does not receive this information, it merely is modulated via 0-10volt to achieve the requested water temperature."
You are so right about this. I was evaluating some Tekmar controls. Listed here:
...and while studying them, I came to this revelation: they are great, but many of their functions are just overlapping with what the Knight WHN055 already know!
Things like the ODR and water inlet, supply and system supply sensors. Heck, the WHN055 has even a built in gas flue sensor. So basically, I would have to pay too much for an external control, and some built-in feature from the boiler will stay unused (money thrown away?). Honestly, the only feature from WHN055 that I feel like missing is this: continuous indoor temp feedback sent to the boiler (as opposed to on/off).
You know something? NOW I'm starting to understand what Mr. greeny had said by "If you install a Vitodens 200 its the cheapest communicating t-stat on the market!" So basically, while trying to find a solution of a more advanced, continuous "indoor feedback" for Lochinvar, I suddenly realized that Vitotrol is something great and a pity to not have it :-) Eastman, do you know what would be the simplest Tekmar control which could be interfaced into the BMS 0..10V input terminal and able to only provide indoor feedback and leave the built-in ODR control of the WHN055 in place? Or I'm asking the impossible?
And the other open question is still that "SYS PUMP IN" signal.
Thank you.This post was edited by an admin on April 22, 2013 7:22 PM.
SYS PUMP INNo idea, the manual is super confusing on this. If I had to guess, I would say it functioned in the same manner as the BMS input, but as you've noted there doesn't seem to be any parameters associated with it. Call a rep and find out for us --I highly doubt it does anything complex but who knows?
"Btw, the service manual is quite interesting, because it mentions that
the BAS 0..10V input plug can be configured in two ways: to mean a
firing rate (a Power percentage) or a setpoint value (see same Page 26,
section "BMS Type"). It is a hint that you may be able to connect there
not a true, full-fledged BMS, but a smarter thermostat, which would be
able to shift the ODR heat curve up and down, that is, something similar
to Vitotrol 300?"
It wouldn't shift the ODR curve. The BMS input overrides the system. The 0-10volt either controls flame %, or setpoint temp. The on board ODR logic is not part of the loop. This is why a 3rd party boiler controller must have its own ODR logic.
Stratos ECOAh, I think you are right. The ECO is being considered the "dumbed down" version of their Stratos line. Please take a look at those 2 PDFs that I attached in the next message - perhaps you could infer more info than myself on their possibilities?
SWEI, you were suggesting in another thread the use of the Bell & Gossett's EcoCirc e3 pump? Is such thing generally available on the US market?
I'm basically looking for a way to combine the best of two worlds: the fact that WHN055 can modulate a var speed pump (i.e. through something like a Taco Viridian or variable voltage pump) with the more efficient ECM techology. And can't find a solution yet.
Thanks.This post was edited by an admin on April 22, 2013 7:48 PM.
Minimum FlowFor a WB2B19 is 1.6gpm on a 35 Temp Rise. Boiler btu/hr output on low fire is 28K
Low Fire 28,000 /(35x500) = 1.6gpm
High Fire 61,000 / (35 x 500) = 3.5gpm
Just change the temp rise in the equation for a 20, 25 or 30. So if your boiler pump can modulate from 1.6 to 3.5 to match the boilers btu/hr out put at any given time in the system then it's a home run. Your right, like they do across the pond.
The golden boiler parameterAha, cool! So in fact the boiler does not know about flow rates, nor it's having any special flow detector/counter. And the magic thing that it knows seems to be the max Delta-T allowed?
So basically, the min flow can be calculated for any boiler using this formula (UHF-driven)?
minFlow = min_fire_btu / (500 x max_delta_t_allowed) ?
[btw, it's interesting that Viessmann is specifying the min BTU output according to DOE. Lochinvar specifies only the max outuput, and expressed in AHRI ratings. I don't know the difference - is that I=B=R type of rating?]
In our WHN055 case, it would be 11,000 / (500 x 35) = 0.628 gpm ? It's nice if it can sustain such low requirement.
I guess one third of the house (one floor) could sustain that for sure. Considering that the main floor will have 6 double-convector rads plus one bathroom towel rad. Aall rads being calculated for 130F/110F operating temp and 76F room temp i.e. 24 celsius and something. The total heat loss for the main floor is 12,429 BTU and I have sized the rad including a 20% additional margin of safety. So basically, at 130/100F (dT = 20), the total flow for that one floor will be 12,429 * 1.2 / (500 x 20) = 1.5 gpm.
The other question is: how one can figure out the max Delta-T rise that a particular boiler supports? SWEI was mentioning about a "boiler ∆T alarm level" - where can that be found?
It would be interesting also to know what pump driving scenario would be more optimal in my particular case: a varspeed pump driven by WHN directly via 0...10V out signal, or an Alpha/Stratos/Bumblebee pump (still connected to the boiler relay because let's say we are willing to trade off the Grundfos "adapt/learn" feature for the ability to have the pump powered on and off by the boiler's relay).
And finally: could we dare to use TRVs (e-TRVs like Danfoss Living ECO) in such direct pipe setup - where also a varspeed pump is driving the show?
Assuming that the whole mainfloor (which will have the termostat anyway) will not have any e-TRV. Out of 14 total rads, only 5 will have eTRV: 3 bedrooms (3 rads) on the upper floor, and 2 rads in basement. 9 rads (including the 3 towel rads which are for all bathrooms) will not have TRVs.
Thank you.This post was edited by an admin on April 22, 2013 7:56 PM.
Max Temp RiseFlow rates are in every manual. I would call Loch and find out from them the min flow rate they want across the HX. I know what Viessmann allows and there reasoning for it.
Do you not have to use the Loch Supply sensor when utilizing the variable pump feature. I believe the boiler is going to vary the speed of the boiler pump off the need of the system supply temp. When piped pri/sec it accounts for the down stream mix. As the boiler delta shrinks it will head to low fire, change the pump flow rate until it sees the down stream temp need diminishing then speed back up as the boilers delta increases and supply out decreases always trying to keep from going off on high limit until the zone is satisfied.
Thus the need of the primary flow rate not having to match the system flow rate.
I had a nice conversation today from someone I know that had a hand in designing the Weil Ultra control. That boiler will not lock out until it sees a 59 degree delta. Found that interesting. Just goes to show how much you can play around with mod/cons. I pretty much know there is a lot of conservative thinking given in the manuals.
delta T!"I believe the boiler is going to vary the speed of the boiler pump off
the need of the system supply temp. When piped pri/sec it accounts for
the down stream mix."
My interpretation was that the variable boiler pump output signal is really just locked to the modulation rate. So one would still have to select an appropriately sized pump for the desired delta. The assumption being that if modulation gets cut in half, and pump output gets cut in half, than the delta must remain about the same. I really don't think there is a feedback loop to an actual measured temperature delta except indirectly via the normal target temp control.
Well,we can't know that the output signal driving the var speed pump is tied to the modulation/firing rate. Maybe both the firing rate and that var speed pump signal are driven by an upstream logic/controller.
Also, "I really don't think there is a feedback loop to an actual measured temperature delta except indirectly via the normal target temp control. " -- well, the WHN055 has those 3 temp sensors: inlet boiler temp, outlet/supply boiler temp and the externally attached "system supply" sensor which Cris mentions that it should be installed. So, basically the internal controller really has a feedback loop, exactly like the bumble bee has, or I'm missing something?
Also, besides those 3 sensors, there is 1 more: the high limit temp sensor.
We can't know for sure...But what is the simplest explanation? Slaving pump modulation to the firing rate achieves a near constant delta without an additional feedback loop.
I seewhat you mean now. The fact that the boiler may wish to "cut corners" and not making good use of those 3 temp sensor :-)
If that's the case, it's still good - it makes the system as a whole more tolerant to mistakes/load mismatches. Especially in directly connected loops. Because at least will be able to sync the pump to the firing rate.
But now, the question is whether the Bumble bee or the alpha would be better? But not being driven by the WHN, how could WHN be in sync with what such type of "independently acting" ECM pumps (especially the Alpha, which doesn't come with temp sensors)?
It's very puzzling: I've always wondered how come those systems across the pond were so tolerant to boiler oversizing or forgiving to piping (and no P/S), even with water tube boilers such as Vaillant, Viessmann or Bosch or Ariston ? That integrated varspeed pump plus the fact that combi units are used in most of the cases, contribute to that. Honestly, when my father or other companies back there were installing these, they have never bothered to do head loss calculations or concerned about min flow rates :-). Heck, they weren't doing even a detailed heat loss calculation. They were just picking up a combi boiler unit appropriate in terms of power to the total square footage of a house or an apartment :-)
And now, I have got so preocupied with formulae and rigurous sizing...Don't get me wrong - it's a good thing, making us aware of how the systems work and getting closer to an ideal "impedance match"/resonance condition.
Those systems...probably had an integrated bypass inside the boiler. This is quite common and you will find many examples with even a small expansion tank. Euro combi units in particular are expected to be amicable to kitchen or bathroom installations and there is a major incentive to keep things as appliance like as possible.
Crazy thought...With the cost aspect left aside, WHAT IF I could just buy a Grundfos Magna 32-60 plus a "Geni Expansion Module" for it, and use that as the var speed pump?
The pump costs about $507 and the interface module is $166. The pump is 1/6 HP.
I just realized that we have here what's called a Split-Phase electric power system:
so basically, we have 220V AC power for the electric stoves and washer/dryers? I now realize that when I have replaced an older electric range by a gas range, the power outlet was something big, with 4 terminals. And had to buy an adapter to connect between 2 "live" terminals, of which one was not in fact a real live but a sort of common mid-tap from a transformer. In order to be able to connect my new gas range to 110VAC.
So, we do seem to have 220V AC here, mono-phase. I have a similar power socket in the furnace room, exactly near the Rinnai tankless. So, using a Magna wouldn't be a problem, would it?
But what about flow requirements for that pump? (besides being kind of pricey :-) )
About those boiler back there, yes indeed, I forgot to mention that they do have an integrated bypass, and the expansion tank is built-in, flat-sized (about 7 liters, what's that, less than 2gallons). And yes, they are mounted in kitchens, bathrooms, hallways or even in balconies/outdoor (but many apartments have the balconies closed, with uPVC windows).
So, if we install a simple bypass here, and a varspeed pump (if driven by boiler), or a Delta-P/T pump without bypass, would that solve all the problems of the Universe ? :-)This post was edited by an admin on April 23, 2013 9:15 PM.
Let me backtrack a bit...**********
Hypothesis is wrong. Apparently there is another feedback loop.
Suppose my hypothesis regarding the variable output signal is correct. Take a look at some documentation for pumps that support 0-10 volt input signals. I might be wrong, but I think the common modulation technique ramps the pump's power (commonly called speed). (There might be other ramp options like delta P, but I can't remember.) This doesn't imply that the flow rate is proportional --this is dependent on the relationship between the pump's characteristic performance curve and the variable voltage signal. Typically there are several options.
Lochinvar wants a pump that is set for linear output. Translation: they want a response to the signal that equates to a nice straight pumping curve with a slope of 1. Normally this is not the case, but these pumps do indeed have an electronically synthesized linear curve as an option. So what's the problem? The assumption here is that the hydraulic resistance is constant. If the hydraulic resistance is variable, the flow will vary independently from the control signal and hence the constant delta T will in fact fluctuate. For example, if you had a TRV based system or zoned manifold system, the hydraulic resistance is independently variable and boiler based constant delta T control cannot be assumed. So essentially, this feature will only work as advertised if the resistance remains constant, or the primary loop is hydraulically separated. This isn't necessarily a bad thing and removing a possibly unstable feedback loop is good, but it definitely makes direct pumping much more tricky if your system revolves around controls that vary the hydraulic resistance. Also, I think it's important to realize that this control scheme, as I mentioned earlier, is more stable (in the sense of boiler hx flow) than a regular fixed delta P pump. A direct pumped regular delta P maintains constant pressure in the face of varying hydraulic resistance, while a regular fixed speed or boiler modulation slaved variable would increase its delta P and not allow flow to slide quite as much.
Regarding the Magna: what's wrong with the Stratos? Isn't that more in your size range? Look up NEMA 6. The circuit needs to be configured for the correct amperage. You shouldn't use an adapter.This post was edited by an admin on April 24, 2013 8:17 PM.
Varspeed pumps-"This doesn't imply that the flow rate is proportional --this is dependent on the relationship between the pump's characteristic performance curve and the variable voltage signal."
-"Lochinvar wants a pump that is set for linear output. Translation: they want a response to the signal that equates to a nice straight pumping curve with a slope of 1. Normally this is not the case, but these pumps do indeed have an electronically synthesized linear curve as an option."
Some pumps have 2 modes: linear and "proportional weight" or something. The latter I guess reflects the reality better, but since the WHN and maybe other devices across the pond expect linear response, we have to config for linear.
-"So what's the problem? The assumption here is that the hydraulic resistance is constant. If the hydraulic resistance is variable, the flow will vary independently from the control signal and hence the constant delta T will in fact fluctuate. For example, if you had a TRV based system [..] the hydraulic resistance is independently variable and boiler based constant delta T control cannot be assumed. So essentially, this feature will only work as advertised if the resistance remains constant, or the primary loop is hydraulically separated."
--Indeed, sounds logical.
-"Also, I think it's important to realize that this control scheme, as I mentioned earlier, is more stable (in the sense of boiler hx flow) than a regular fixed delta P pump. A direct pumped regular delta P maintains constant pressure in the face of varying hydraulic resistance, while a regular fixed speed or boiler modulation slaved variable would increase its delta P and not allow flow to slide quite as much."
So, if I understand correctly, this boiler-driven type of connection would still be better than a Delta-P "standalone" pump (i.e. not having anything connected to its input, if having such inputs)? But what about a const Delta-T pump such as Taco Viridian or Bumblebee (again working separately)? Would the WHN-driven model still win?
-"Regarding the Magna: what's wrong with the Stratos? Isn't that more in your size range?"
--Well, I wanted the Stratos very much, since the ECO model is 110V. But unfortunately it doesn't seem to support variable voltage interface as attachment. And even if I were to go with their non-ECO model, it would be 230V based and also couldn't find the exact type of interface available for purchasing (only that LONnetwork module was available).
-"Look up NEMA 6. The circuit needs to be configured for the correct amperage. You shouldn't use an adapter. "
--That's right - I must not use an adapter, but plug a Nema6 plug (the one used by high powered stove ranges or laudry dryer). I have checked in the electrical panel - there are two fuses allocated for that circuit. I think I'm ok.
Since my father hasn't left by plane yet (he will fly in this Saturday), I still have time to ask him to buy something rated 230V (50Hz vs 60Hz doesn't matter too much I guess since the ECM variable driver is re-converting to DC anyways?) - I could ask him to buy something from there. Would you have something in mid?
He asked at a store about ECM pumps, and they were mentioning an Italian brand, DAB EVOTRON 40/300 . I'll check into that.
Interestingsounds good, thanks for explaining it and recommending the installation of that sys supply sensor (which makes sense even in a direct loop scenario - because Lochinvar is clearly stating that even in a P/S setup it should be places as much downstream as possible, to get a realistic temp reading).
I've sent an e-mail to the Lochinvar rep about the min flow rates and max temp rise, plus clarifications on the varspeed pump and that bizzare 0-10V dc input signal ("sys pump in"). Waiting for a response.
0-10 VDCFor the system pump is simply giving an a BMS the opportunity to see it, control it. But if BMS was controlling the pump then BMS is also controlling the boiler as far was telling it water temp needed. No BMS will take away the boilers firing logic. We do the same thing with Vitodens 200 though I still can't figure for the life of me why I want to give control of my boiler to Amercian logic. Most engineers know nothing about how a mod/con works.
I probably have 100 prints in my office and have yet to see one in 25 years showing the boiler side flow less then the system flow at design. They have fallen into the 20 Degree Rise Trap like everyone else. I do though have a couple that have seen the light after I've redesigned there spec, got it approved and those systems are running and not missing a beat.
Think about a spec. Boiler output is 285,000 need a pump that moves 28gpm. Since when have you seen a buildings heat loss exactly what the boiler puts out and when have you ever seen the primary side influence the secondary side flow rate'? Ok, I got off subject but it's the same in a residential system.
It's not the rise you want to ask, it's what is the minimum flow at low fire so I don't flash to steam.
BMSOk, so the "SYS PUMP IN" 0-10VDC signal would be for the BMS to read a pump that can supply such type of analog output. And that BMS (which can connect to WHN055 in two ways - either through the 0-10V "BMS IN" plug, or via the ModBus module, the latter being like a KMBus from Viessmann hehe).
And based on that reading, the BMS would be able to make other decisions and command the WHN055 modulation rate (it doesn't seem to be a water temp rate, but really a mod rate, according to the service manual - but who knows, as you said about Viessmann never losing it ability to ctrl firing rate, maybe that mod rate is just an input into some other module in the controller, and it's just an 'influence', so basically the controller can still decide the real modulation to proceed with).
Interesting. It's like the Lochinvar's mainboard is trying to fill a "gap" - helping out some BMS systems that are unable to connect to such system pumps directly. So basically, the WHN will convert that analog reading into some digital value in an internal register I guess. I was also intriguing that it was mentioning it only in conjunction with a primary loop / primary flow.
Thanks for the hint - seems logical now. So I shouldn't put too much hope in that interface.
About the question to the rep, ok, let's see first the answer to the most important question - the HX absolute min flow tolerated. Thx.
Chris, about "I probably have 100 prints in my office and have yet to see one in 25 years showing the boiler side flow less then the system flow at design. They have fallen into the 20 Degree Rise Trap like everyone else." -- I'm afraid you were too dense for me, can't understand. Are you trying to suggest that that's the biggest advantage of a P/S hydraulic separation - different flow (and head) needs and the primary/boiler circ should typically had a significantly higher flow than the secondary? But if we aim for higher Delta-T in the boiler (to favour the condensation, due to lower return temp), wouldn't that imply just the opposite? Lower gpm in the boiler (35delta) and higher gpm in the secondary circuit (20 delta)?This post was edited by an admin on April 23, 2013 8:37 PM.
Please Don't Read IntoMy theory based on hundreds (thugh will say thousands but I can too)
f designs and installs. Some think I'm as nuts as Sarah Palin. Ask Loch what they need on the min flow rate side before the boiler will flash to steam. Unlike others my belief and theory based on real life installs here in the US bounced off what is done done across the pond with variable speed pumps is that the boiler flow rate or primary side does not have to match the secondary side.
The goal is to be able to remove the btu/hr created by the heat source to the secondary side. Yes, at times because we zone here it cannot be done but it should be done as to provide the boiler the best opportunity to provide the best overall seasonal efficiency while protecting the source from unwanted wear and tear.This post was edited by an admin on April 23, 2013 9:00 PM.
Different approach, "conveyer" metaphoryou meant?
In other words, the Europe folks tried the one-circuit/one-flow approach and counteracted the "variances" in the system through the use of a var speed pump?
Whereas you think that the "load variance" aspect could be tackled differently, by using the hydraulic separation? Using the "btu 2-conveyer" idea? And even better, by combining the separation also the var speed pump, you would get the best hybrid?
Someone was saying that the hydr. separation somehow came in the market due to the non-condesing boilers, and a need to keep the return temps back into the boiler high enough, to prevent the boiler from condensing/rusting the inner materials?
From an energy transfer perspective, isn't a P/S coupling at disadvantage? I feel that "something" gets lost in this type of connection. In the sense that, instead of transmitting the full thermal energy of the water from the boiler's supply mains into the rads, you deviate part of that back into the boiler.
Wouldn't take longer for the final rads circuit to get the needed BTUs that they would get through a direct connection? I admit I have't studied these aspects too much, but I feel (intuitively) that there are some negatives with the P/S, besides the obvious (impedance matching and separate deltas and flows) advantages.This post was edited by an admin on April 23, 2013 9:01 PM.
The True Reason In My OpinionFor hydraulic separation...Here in North American, It is to protect the less talented from scorching the boiler. Across the pond like Viessmann and many others do, it's to lessen the boiler pump flow rate to allow the system flow rate to take the btu/hr created to the emitters giving the emitter the best opportunity to take those btu/hr out to the space.
We have to dumb down the European technology to fit the installers here in the name of the almighty dollar and our 1950's systems. In all honesty, my rationale comes from the European side and while open to the American side don't take it to the efficiency side.
We try to adapt current technology to 1950's type designed systems instead of taking 1950's designed systems and adapt them to current technology. Look at the frustration you had. A guy can turn a wrench and solder a joint but he couldn't tell you truly how the system works though you could feed you a line of bull..
Please call Loch and find out the min flow rate a low fire and high fire before the boiler will flash the water to steam and ask what that flow rate is based off of..
So the reason for the P/S separationis mainly for allowing situations whereas the heating circuit (according to its design conditions) would ask for much higher flow rates than the one tolerated by the boiler/HX ? That is how I understood "Across the pond like Viessmann and many others do, it's to lessen the boiler pump flow rate to allow the system flow rate to take the btu/hr created to the emitters giving the emitter the best opportunity to take those btu/hr out to the space." And with any efficiency-related considerations left aside.
Or, were you maybe implying more - such as, EVEN when the system/heating circuit required flow is still within the boiler's accepted parameters, the P/S config is still beneficial, in the sense that it allows the boiler to work at higher dT and somehow work less (or modulate less)? I admit that it's unclear to me.
Some answers from my Canadian Lochinvar rep[some are still unclear]
Q1: What is the max temp rise (Delta-T) which the boiler can sustain without going into 'alarm' mode.
A1: On Page #65 of the manual under the “Protection Features” the max Delta T is 55F before the boiler reduces the fan speed and if the Delta T reaches 60F the boiler will shut down.
[I have to admit that I missed that paragraph] This is very in sync with what you were saying Chris, about your guy who was deeply involved in the design of another boiler.
Q2: What is the minimum gpm flow rate that Lochinvar wants across the Heat Exchanger - calculated at the minimum firing rate of 11,000 BTU/h and the maximum temp rise supported by the boiler.
A2: Based on the information in the manual the constant speed pumps will maintain 5 gpm but changes with VSP.
[Obviously that's wrong. I re-asked him.]
Q3: What fine-tune parameters are available in the "Smart Control" logic for the customization of the "Const Delta-T" operation which seems to be supported via "0-10V BLR PMP OUT"?
A3: The Knight Smart System controller will always try to maintain a 20F Delta T (Default) but has a range from 15 – 25 using the PC Software.
Q4: In order to use that "0-10V BLR PMP OUT" signal, would a varspeed pump setup be compatible with a direct piping circuit?
A4: Yes you can use a VSP using the “0-10V BLR PMP Out” connection in a system flow application. The outlet sensor looks at the outlet water temp to maintain the proper Delta T (20 gpm as a default) If the Delta T increases the VSP will decrease in speed to maintain proper GPM flow rate.
[That sounds good - it invalidates somehow Eastman's hypothesis - just to be sure I re-asked if the internal sensors will be actually used for that and not just a direct sync with firing rate]
Q5: What is the "0-10V SYS PUMP IN" plug used for?
A5: The “0-10V SYS Pump IN” connection is for a Primary /Secondary system piping arrangement for the VSP system pump so having your VSP system and VSP boiler pumps connection the low voltage board what happens if the system pump decreases in speed so will the boiler pump to prevent the primary loop having a flow rate having a higher flow rate than the secondary piping.
[That's cool - it invalidates the assumption that only an external BMS system can use it - seems to indicate that it's a way for the boiler's logic to sync the flow of the primary (assuming that a VSP is also mounted in the 0-10V BLR OUT) with what happens in the secondary. But still does not say what kind of pump exists for a secondary circuit, which could provide 0-10V output back into the Knight.]
Q6: Can Lochinvar give an example of such smart pump, which can provide an analog 0-10VDC output signal which the WHN055 could then be able to read via "0-10V SYS PUMP IN"?
A6: On page #37 of the manual it gives you 4 different pump manufacturer’s and explains the VSP pump options and setup. VSp pumps are being used more and more in hydronic systems everyday and some of the advantages are reducing Electrical cost, better system boiler / flow relationship and able to better outlet temperature control.
[This seems to be wrong - that page of the manual give only two VS pumps as example, not four: Grundfos UPS26-96FC/VS and Taco 0013 IFC VS. The other 2 examples are for the same pumps, but at 50% ratio. Also those 2 pumps seem to be a classic VFD/Variable Voltage type of pump (non-ECM that is) and ALSO, they do not provide output signals, they only have inputs.]
He has also mentioned that he's having a VSP pump installed in a training room in Burlington, Ontario and he would be happy to show me the setup.This post was edited by an admin on April 24, 2013 7:29 PM.
holy cow!!!!!!It is way more sophisticated than I had thought!!! Those are features that I would think secretly: "wouldn't it be cool if it did x, y, and z?" --d***mnnn.
yesand also their HX seems to be very tolerant. Btw, last evening I looked also through Triangle Tube's manual, and Lochinvar seemed to have inspired from that technology, but they brought in a lot of good stuff in terms of control.
Btw, all WHN's suggesting piping configurations are always showing the boiler pump not pumping away, but mounted close to the return/boiler inlet, and pumping into it.
Now, were you able to undestand something more than me, about the "0-10V SYS Pump IN" ?
Synchronization"Q5: What is the "0-10V SYS PUMP IN" plug used for?
A5: The “0-10V SYS Pump IN” connection is for a Primary /Secondary
system piping arrangement for the VSP system pump so having your VSP
system and VSP boiler pumps connection the low voltage board what
happens if the system pump decreases in speed so will the boiler pump to
prevent the primary loop having a flow rate having a higher flow rate
than the secondary piping."
It sounds very much like the SYS PUMP IN signal is used to synchronize flow across a hydraulic separator. I'm not sure if I believe it but that sure sounds like what it does. The boiler probably allows this only when possible, overriding as necessary.
I'm also very surprised there is an additional feedback loop for boiler controlled delta T. The manual really does not read that way, for example, there was no discussion of setting the delta T electronically. I'm wondering if there is another manual for the software that covers this?
Basically WhatThey are doing is keeping the primary (boiler) side flow rate matching the system side so there is no mix down stream for the boiler to have to increase it's water temp in order to overcome it. It also eliminates the elevated boiler return temps when the flow of the primary exceeds the secondary.
It's the same thing I've been saying in the Delta-T threads. In those threads I wanted my boiler pump sized for the larger rise and my system for a 20 Delta so the system side could take my boiler side flow rate away from being able to head to the boiler return and elevate my boiler return temps.
Ideally I'd want the type of control the Loch is giving me for my pumps.
Now, which system/secondary pumpis able to provide such output feedback?The control possibilities and pumps availability look ok on the boiler/primary side (controlled by the other signal). Only the seconday/system circuit look SF / un-concretized now.I have access to these models:-DAB Evotron: http://www.dabpumps.com/en/page_60.php?serie=293&linea=2&language=en&minisito=-DAB Evotron SAN (can't see the difference): http://www.dabpumps.com/en/page_60.php?serie=304&linea=2&language=en&minisito=-DAB EvoPlus: http://www.dabpumps.com/en/page_42.php?news=136The smallest Evotron (40/300 model, 1 1/2'' coupling, 4 meters head, 27W max consumption, max 2900 rpm, 10 bar max operating pressure, 230V @ 50 or 60Hz) costs about $200. And, very bizarre, a Magna 32-60 costs about $1,000 over there and here it's $500-550 :-)I'm not sure if any of them can output that 0-10V signal though. But inputs, yes.This post was edited by an admin on April 24, 2013 8:51 PM.
But Chris, you only get...25 degrees!!This post was edited by an admin on April 24, 2013 9:47 PM.
Guess You Didn't GetThe logic why I wanted my boiler pump on the 40 rise not the system side.
Either WayYou are attempting to match flows. With a fixed flow for primary, you are going to wind up with the highest DT(lowest flow). If the primary and secondary pumps will match each others flow, who cares.
Exactly PaulHaving variable speed on both sides gives you that advantage and in all actuality eliminates the need for pri/sec piping or as I call it, boiler protection for a mod/con.
Folksget hung up on imbalanced DT's primary to secondary. If you just concentrate on balancing flows primary to secondary, which is what you want, it just works out that way. Engineers would have trouble wrapping their head around it, because it appears to be a system 'Out of Balance". It's not, and I would argue that it is as close to being in balance as you can make it.
But doesn't that create a contradictionof terms, when you say "Having variable speed on both sides gives you that advantage and in all actuality eliminates the need for pri/sec piping or as I call it, boiler protection for a mod/con."
How can you have var speed on both sides without having a pri/sec piping?
Do you see the conflict? :-)
Or you mean "sides" in a diffent sense. Guys, I cannot follow you anymore :-)
Too much hermeneutics. Why are you afraid that the enlightment will get to too many folks? The enlightment is always beautiful and truth is always good for everybody.
I'm sorryLet me clarify. You wouldn't need 2 pumps nor pri/sec unless the pump could not overcome the pressure drop of the boiler and system at design flow rate or your low end flow rate is too small.
The boiler will modulate based off the temp rise. Yes folks that's what speeds and slows fan speed. ODR is a temp target. Temp Rise is the aiming device the control logic uses to achieve the temp target.
Now you are coming homeVery well said and clear now. Yes, indeed, this makes perfect sense.
Thank you Chris!
Long time no seeHi everyone,
We have just finished our DYI hydronic project around August this year. Now I finally have a bit of time to report back with results. I have posted some pictures into a new thread, if you are interested. Wished to post even more pictures with the rads and piping through the house, but there is some limit in how many pictures can be posted I guess.
Thank you all for helping us with this project, especially to Chris, who had the inspired idea of suggesting us the Lochinvar. It proved to be an excellent choice. Thank you Chris!