Heating Help

Mistaken?

@ May 19, 2012 2:45 AM in Lochinvar listens....

I think you mistook what I said and I'm not sure what your intentions are. A lot of early North American Mod-Cons - even a few to this day, including the Knights (WHN, KBN, WBN) pipe the direct vent air directly into the fan, where as boilers like the Viessmann Vitodens, or Buderus GB142's, or the Triangle Tube's pipe the direct vent into the cabinet and let the fan pull air from the cabinet. This is beneficial for several reasons 1) Pre-warms the intake air which slightly increases combustion efficiency 2) Lets the cabinet act as a big slow spot for intake air piping so any debris can settle out 3) Keep the mechanical room cooler as the heat exchanger is not projecting it's heat into the mechanical room but instead using this heat to prewarm the intake air 4) If there was ever a venting leak somewhere in the cabinet from a seal or gasket, or something like that, it would just get reingested instead of spewing out of the cabinet into the boiler room. I fail to see how any of this would compromise reliabliity or durability of the boiler unless you had a major venting leak out of the flue which was causing the boiler to inregest a hell of a lot of it's own flue gas back into the intake.
Since Mod-Cons are mandated in England, you probably have a lot of hack installers who don't neccessarily install them in favourable conditions. Perhaps some of the mod-cons are oversized, or installed in old systems with a lot of debris which can cause premature erosion of gaskets or seals, or things in general aren't set up right. European made heat exchangers which are quite common over here, such as the Giannoni do not have very thick pipe walls in the tubing. I believe 0.7 mm is their thickness compared to the Vitodens which is 1.5 mm. Also, you have A LOT more of them out there due to this law requirement so your sample size to find failures is a lot more common. Perhaps pricing over there is a lot cheaper for new units versus the cost to have a tech replace a gas valve or combustion van, so perhaps more people might opt for the latest and greatest. Who knows the rationale. But since Hydronics over here on our side of the water are a smidgeon of the heating market in all honesty we don't have the scale or sample size for a worthy comparison to write a similar article to the one you read about combi boilers. No one installs combi boilers over here. We want large indirects so we can take long, hot showers.

More

@ May 18, 2012 1:39 AM in Lochinvar listens....

At least they made a bit more "european" as far as having the direct vent air intake pipe into the cabinet, making the cabinet what appears to be sealed or semi-sealed - and using the cabinet as a big fat spot in the direct vent air intake piping to let dirt settle to the bottom as well as the heat exchanger will pre-heat the intake air instead of their knights where they hard pipe the PVC directly into the fan/venturi where you don't get the benefit of any pre-heating.

I'm not much of a fan of the Giannoni heat exchangers either but they do perform well and are quite compact for what it's worth. It's just their longetivity that is the question for some due to the tube forming characteristics as well as the thickness of the tubing walls. I agree though that it's nice to see some lower turn down boilers. Lochinvar owns that crown now (and has for a while, with their 10,000 to 50,000 Knights, now their smaller 9,000 to 40,000 CADET) as far as having the boiler with the lowest minimum firing rate.

Forced Air/Hydronics

@ May 5, 2012 1:53 AM in Why Is the US Always Last

Plus, the hydronics market here is relatively quite small compared to that in Europe. Damn Furnaces!

Not always debris

@ May 1, 2012 12:52 AM in Weird debris in Lochinvar HX

Unless the debris is fine enough to penetrate the mesh into the combustion process, a lot of stuff just sits in the burner can/cylinder until someone pulls it apart and cleans it at an annual service. I've opened up burner cans with some dead flies in them, perfectly intact - they could have been there for at least a year or so.
Boilers that pipe the direct vent direct into the venturi will see more debris as was mentioned. Those that pipe the air into the cabinet and then the venturi/fan pull their air from the cabinet will have less issues with debris as the interior of the boiler cabinet acts as sort of big settling point and everything falls to the bottom of the cabinet. Boilers like the Viessmann Vitodens or IBC SL20-115 are examples of this.

Last I checked Lochinvar does offer an air filter housing that you can install on your direct vent air intake piping that will significantly reduce debris getting into the combustion process.

Indirect vs output

@ February 3, 2012 1:27 AM in Indirect water heaters

The Viessmann's Vitocells have a very high output coil for the size of tank as do the new Lochinvar Squires - they both heat up very fast.
I'm also partial to the Bradford White RTV series at the moment because I have installed a fair number of them and I've also yet to see or hear of a failure of one. They are 444 stainless steel which handles chlorides better than some 300 series stainless tanks. They produce a Dual Coil Indirect the RTV-75D. Not sure if 75 gallons is too big but this dual coil tank has good output.
I think, could be wrong, but I think AIC's new REX indirect is sort of like a turbomax concept (reverse indirect) but made out of stainless, but I'm still trying to get some product specs on it - just saw some basic pictures and info on their website on it.

Lochinvar knight

@ January 28, 2012 9:02 PM in Need about 18,000 btu's to heat small apartment any ideas.

How about the Lochinvar knight whn05
5 which modulates from 11000 to 55000 input?

Bradford White RTV series

@ January 17, 2012 10:35 AM in chloride level

dp

Bradford White RTV series

@ January 17, 2012 10:15 AM in chloride level

Or a Bradford White RTV Stainless steel tank made out of 444 stainless steel which is apparently nearly immune to chloride attack ( much better than 300 series stainless steels). 

Bradford White RTV series

@ December 28, 2011 5:44 PM in Megastor Indirect HW Tank and Chlorides

You might want to consider switching your indirect to a Bradford White RTV series stainless steel indirect. They use 400 series stainless (type 444). 300 series (316L as an example) are not fond of chlorides but most 400 series stainless tanks are no where near as susceptible to chloride attack or chloride stress corrosion cracking.
http://www.alleghenytechnologies.com/Ludlum/Documents/al444.pdf (scroll down to page 2 of this document in the middle where it talks about chloride stress corrosion cracking)

Temp Rating, Quality

@ December 27, 2011 12:07 AM in PVC v. CPVC v. SS

I am not a big fan of PVC of CPVC. A few reasons why
1) Not as high of a temp rating as other products out there. PVC is 149 F if I'm not mistaken, CPVC is 194 F.  Unless the boiler is only doing low temp radiant heating or snow melt all it's life, you can rule out PVC just about all of the time as far as being the right exhaust vent material due to it's lower temperature rating. CPVC, when you factor in flue gas temps at higher firing rates if you're pushing 170-180 degree water will have it's boundaries pushed potentially, especially in a heat exchanger that needs love/maintenance which may send more heat out the flue than neccessary.
2) The environmental factor - CPVC and PVC are called the Poison plastic for a reason - these plastics apparently carry some metal for stabilization - do some searches on google for more info.  They generally aren't known to be as easy to recycle as other plastics as well.
3) On certain heat exchanger designs, some have raised the issue of the potential for chlorides to leech out of PVC and CPVC and drain back onto the heat exchanger through the condensate. Stainless steel and chlorides do NOT mix well and will cause premature failure of some grades of stainless steel. Of course CPVC and PVC manufacturers of their certified vent materials will tell you their products are inert, but I've heard some suggest otherwise as well. Enough to create doubt in my mind.

For the reasons outlined above I would prefer Polypropylene plastic (if I was using plastics) which does not carry metal stabilziers as far as I know, is one of the most chemically resistant plastics available to deal with flue gas, hydrocarbons, etc., has a higher temperature rating (230 or 248 F depending on which standard you are certifiying it to) than PVC, or CPVC, is very recyclable and more environmentally friendly, about the same price as CPVC roughly, will not leech chlorides back onto a heat exchanger, the list goes on. Stainless steel is another option as well with an even higher temperature rating than PP obviously, being metal, but costs noticeably more, but still a noteworthy option and sometimes it is specified on a job by engineers for particular reasons.

Your installer knows what he is talking about.

@ December 14, 2011 9:37 PM in viessmann help

In a perfect world, a well designed hydronic heating system would be sized to provide exactly enough heat to counter the heat loss to maintain a set temperature as per your requirements in each zone as outdoor temperatures move up and down thanks to weather responsive controls (outdoor reset).  Your zones/loops would be balanced as such to distribute the boilers heat evenly and in theory you would not need thermostats. Your boiler would put out just enough heat to maintain the temperature, and as such your condensing boiler would see maximum efficiency since it'd be putting out the lowest water temperatures possible for maximum condensation of flue gas and recovery of latent heat transferred to the water.
Not only is it an efficiency measure, but it also helps things last longer. Your stainless steel heat exchanger will last longer if you keep it at a set temperature utilizing minimal burner input instead of expanding and contracting all the time through short cycling from high fire pulse loads from an improperly set up system. Your gas valve(s) and ignition components will generally last longer and suffer less wear and tear.  Pressure regulators on the gas train will tend to not wear and tear as much as the soft seal will not be overworn by the constant closing and opening of it trying to experience positive shut off by the knife edge seat.  All those little things add up to efficiency and cost savings in the long haul.

Do NOT

@ December 2, 2011 12:13 AM in combustion analysis

Cheap out on a combustion analyzer. If you're a contractor (assuming you are) you should be billing for everytime you use the analyzer - something along the lines of an instrumentation or combustion analysis fees. Not only to help you recouple some of the investment into these precision devices, but also to help pay for future calibrations and repairs.  I've used a cheap analyzer in the past and I got what my company paid for. Spend a bit more and you'll get more.

IBC

@ November 27, 2011 11:22 PM in Navien "Mod-Con" Turn down

meplumber - I'm quite familiar with the IBC unit in question - I've installed a fair amount of 15-150's seeing as how I live near Vancouver where they are manufacturered.  I know the story of how they attained 10 to 1 long ago, and IBC recently just had their new SL20-115 certifed at 5.75 to 1.  I have yet to hear of anything about them not being able to sell the 15-150 south of the border after March 2012, however, that's news to me. The 15-150 was certifed around 10 years ago and I've serviced a few of their early 15-150's installed around 2003-ish in the past few years.
It just makes me wonder because the Navien was apparently certified recenty (2010?) mind you again perhaps the certification for firing rate is a different standard or certification as you eluded to.
And as I've mentioned before, I believe the NYThermals Trinity has a higher than 5 to 1.

Navien "Mod-Con" Turn down

@ November 27, 2011 7:49 PM in Navien "Mod-Con" Turn down

First off, I am NOT a fan of Navien, or any of the wanna be tankless models trying to become condensing boilers. But that's just me, don't let my bias interfere with your opinion. However Navien apparently has their new CH series with is a combi series aimed at doing both hydronic heating and domestic hot water all in one. According to Navien they are listed with an ASME H-stamp, AND they have 3 models with turn downs from 10 or 9 to 1 or in that range (17,000 to 150,000, 20,000 to 175,000, and 20,000 to 199,000).
So they are essentially certified with an H-stamp with these turn downs, yet no one else can get these turn down ratios? Is there another standard more common mod-cons (e.g. Lochinvar, Viessmann) must certify to that we don't know about, or another set of rules to get higher turn downs?

Your local Viessmann Dealer

@ November 25, 2011 11:23 PM in Viessmann WB2B Heat Exchanger Cleaning.

Your local Viessmann wholesaler should be able to order them in if they don't have them. It's a little black plastic that says Viessmann on it and I think it was in the $100-130 range-ish.

400 series vs 300 series

@ November 25, 2011 9:55 AM in Glass Lined versus Stainless Steel - Indirect HW Heater

Stainless steel tanks SHOULD last significantly longer than a lined steel tank. The issues of chlorides and stress corrossion cracking is an issue but only with 300 series stainless steels and only in areas where they put a lot of chlorine for disinfection in the water. 
Having said this - this is something I am really curious about. A LOT of manufacturers of the various stainless steel tanks use 316 L stainless steel (many manufacturers), in some cases an even higher/more expensive grade - 316 Ti (Viessmann). 316L and 316 Ti has very high chemical resistance, but they are not immune to chloride attack.  300 series stainless steels cost significantly more than 400 series stainless steels due to the nickel content and nickel prices are through the roof. Yet look at the Bradford White RTV stainless steel tank - made out of 444 stainless steel.  400 series stainless steel is generally immune to chloride attack according to some metallurgical reading I've done and so I wonder why we don't see more manufactuers looking that way?
The other really interesting thing is if you find fact sheets with metallurgical data on various stainless steels, you'll note that when you look at many of the different 400 series stainless steel fact sheets- 409, 439, 444, etc they talk about one of their primary uses as being used for hot water tanks.  But I don't think they are neccessarily talking about building them today with the exception of the Bradford White tank. I think they are talking about them having used these grades in the past.
Here is some more interesting info - I frequent some plumbing sites, and I seem to recall some threads about guys finding 40 and 50 year old hot water tanks during hot water tank retrofits by certain manufacturers that back in the day were made out of stainless steel (before they starting building hot water tanks as a commodity). I have a gut feeling that many of these tanks were probably made using a 400 series stainless steel but don't quote me or consider it fact and I haven't done some research to confirm it. Just a suspiscion right now anyways. 

More info required...

@ November 24, 2011 11:55 PM in Mod-Con boiler and cycling

Gavin,
I guess we're putting the cart before the horse a little bit and should get some more info before making a final recommendation - I have a feeling Chris and I might be fairly similar in our suggestions but I think some more information now needs to be garnered.
Can you tell us more about the types of emitter(s) you have in your 6 zones. Is it all radiant floors or some other type of emitter like baseboards, or panel rads or?
Also, how much DHW do you need? What type of building is this for, etc. ?
What type of DHW tank do you have - an indirect I presume - existing or are you planning on putting something new?  I presume solar buffer tanks upstream of the indirect or in series or?

Multiple boilers

@ November 24, 2011 10:22 AM in Mod-Con boiler and cycling

And do you have to have the Vitodens 200? How about a bank of 3 or 4 Vitodens 100's that modulate from 37,000 to118,000 ? It has the exact same heat exchanger as the 200 (same quality) just less built in control but enough to easily do DHW and one temperature regime. And to boot - you'll have some redundancy as well.  Then you'll have a much nicer downturn, and if you don't have some type of complex zoning with various temperatures but only 1 temperature the Vitodens with it's external pump module and the controller should be sufficient (they also have a staging controller that does up to 8 boilers from KW technologies).  Yes more money possibly and more labour but would better meet your needs me thinks in the long run and be better for the burners and  you could negate the need for a buffer tank as well.

Vitodens cleaning

@ November 24, 2011 2:52 AM in Viessmann WB2B Heat Exchanger Cleaning.

The Vitodens will typically "turd" up fairly similarly to the Giannoni heat exchanger as they are both water tubes with tight fitting gaps between the coils and the impurities do not have as straight of a path out of the exchanger as other designs like fire tubes, or IBC's downfiring water tube. The Vitodens 200 IS a cleaner burning boiler, but they still produce mouse turds that need to be cleaned. Your maintenance schedule however will be dicatated typically after your first heating season where you see how it looks and set up a schedule from there to clean/maintain it regularly.
In extreme cases with the Vitodens I have heard of the condensate trap plugging up and the heat exchanger filling up with condensate which caused the spark igniter to short out. But this could happen in extreme cases with most heat exchangers that are not maintained. The Vitodens is quite easy to service, and Viessmann even makes a tool kit that has all the tools neccessary to take apart their Vitodens boilers (I have one).
Citrisurf 3050, while a bit pricey and sometimes hard to find, is recommended by Viessmann as a chemical for cleaning their Vitodens exchanger and I've used it before and it does a beautiful job. 

Cleaning "tubes"

@ November 24, 2011 2:44 AM in Triangle Tube Prestige heat exchanger cleaning

I guess due to the dimples there is no way to really "punch" the tubes on these boilers?
Based on what you guys have seen, how do you think the 439 stainless steel is standing up on some of your older S/S fire tube heat exchanger boilers? Do you think these are a 20-25 year heat exchanger (assuming the boilers are set up well to run decent burn cycles, etc.) ?
The entire condensing market lately seems to have made a huge shift towards the fire tube style of heat exchanger for various reasons. It appears as though the fire tube heat exchanger manufacturer has created some good business for themselves due to probably marketing their product aggressively on top of the strong price difference now a days between 300 series and 400 series stainless steels due to the skyrocketing price of nickel which is only found in 300 series S/S. And it is really showing up in pricing - I'm seeing mod-con boilers on water tube sets up really coming down - actually surprisingly coming down, even to Vitodens 100 territory, BUT, you're getting boilers with WAY better built in control than the Vitodens 100 could ever wish for, and plus they are also better matched to the heat load to boot in most cases.
I wonder if we will ever see a residential mod-con boiler heat exchanger utilizing alufer tubes that you find on Cleaver-Brooks Mod-cons (commercial) in North America and Hoval boilers in Europe. For those who don't know, basically it is a downfiring fire tube heat exchanger very similar to the fire tube heat exchangers we are all familiar with only the exchanger is made out of 316 Ti Stainless steel and the tubes instead of bieng dimpled, have aluminum fins which greatly increases heat transfer surface and conductivity. It is honestly a SICK design (and by sick, I mean wicked), and takes the fire tube concept to another level.

Giannoni

@ November 24, 2011 2:34 AM in knightly cleaning

Double Post, whoops

Giannoni

@ November 24, 2011 2:34 AM in knightly cleaning

Instead of using a credit card, you could also try one of those plastic dinner knives. They work pretty good.
I believe someone (Trinity?) makes a specific water spraying mounting plate that you mount on Giannoni heat exchangers with a spray wand on it that allows you to hose out Giannoni heat exchangers.