Joined on January 2, 2008
Last Post on November 7, 2013
@ December 27, 2011 12:07 AM in PVC v. CPVC v. SSI 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.
@ December 14, 2011 9:37 PM in viessmann helpIn 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.
@ December 2, 2011 12:13 AM in combustion analysisCheap 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.
@ November 27, 2011 11:22 PM in Navien "Mod-Con" Turn downmeplumber - 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.
@ November 27, 2011 7:49 PM in Navien "Mod-Con" Turn downFirst 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?
@ 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.
@ November 25, 2011 9:55 AM in Glass Lined versus Stainless Steel - Indirect HW HeaterStainless 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.
@ November 24, 2011 11:55 PM in Mod-Con boiler and cyclingGavin,
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?
@ November 24, 2011 10:22 AM in Mod-Con boiler and cyclingAnd 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.
@ 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.
@ November 24, 2011 2:44 AM in Triangle Tube Prestige heat exchanger cleaningI 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.
@ November 24, 2011 2:34 AM in knightly cleaningInstead 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.
@ November 15, 2011 1:04 AM in Flow sensor ??Sometimes guys will install a tankless coil upstream of an electric Hot water tank (so the hot domestic water coming out of the coil goes into the cold tapping on the tank, the hot tapping on the tank goes to the fixtures). That way the the coil does MOST of the domestic hot water heating with oil/gas and the electric tank just acts as a buffer tank sort of to keep the water that was heated by the coil hot (typically minimal electricity use) and to be there for times of peak demand that may exceed the coil capacity. Probably a cheaper and more reliable set up than some time of control system or flow sensor that you suggest.
@ November 15, 2011 12:57 AM in Under Pressure (indirect water heater fail)Sounds like you've got it figured out. I've seen it once before on a BF White combi cor with a steel coil. I have yet to see it happen with a stainless coil but I guess it's only a matter of time.
@ November 11, 2011 4:51 PM in Heating Alert! - LochinvarLooks like a nice addition to their controller, and a good upsell to a customer as an option.
@ September 9, 2011 11:32 PM in Fire Tube Heat Exchangers taking holdIt appears as though ACV has been marketing their fire tube heat exchangers to more than a few manufacturers with successful results. If I'm not mistaken, the majority of these exchangers are made with 439 stainless steel which I'm guessing is significantly cheaper than Nickel carrying stainless steels in the 300 series, especially 316 L, and even more so with 316 Ti. I've noticed pricing with boilers that carry this new exchanger seems 'very competitive' lately as well from more than a few manufacturers. Lochinvar, IBC, and now NY Thermal (Trinity Fire Tube - just saw an add for it today) on top of the already existing Triangle Tube are boilers that I know of that now have models with this heat exchanger. It seems like Giannoni has some competition, and I wonder if Viessmann's heat exchanger will survive a redesign? It's a good heat exchanger but I'd imagine the Germans would have to acknowledge the electricity reduction from going with a heat exchanger with siginficantly less pressure drop.
@ August 30, 2011 9:38 PM in Viessmann Vitodens 100 Combi PlusThis is the Combi add on for the Vitodens 100 Boilers that is now available that Chris was talking about earlier (just found it in a search).
Not a bad option although I STILL wish it modulated lower (the boiler I mean), and I really wish their combi plus option had some buffer capacity to reduce short cycling the boiler for every hot water demand but a shower.
@ August 23, 2011 9:11 PM in 7 DaysWhere is the announcement? Nothing on the Viessmann website either...
@ August 17, 2011 11:17 PM in 7 DaysMy bet is it's a Vitodens 200 that modulates from 31,000 to 124,000 with a small tank built into the boiler cabinet with a heat exchanger coil in it sort of like a mini-indirect.
@ July 23, 2011 2:32 AM in A.O. Smith buys LochinvarSo basically this means Lochinvar is now a public traded company (or part of one anyways), right?
I'm not sure if this is a good thing...I'm in shock as well. Publically traded companies are in it to make money for their shareholders. If you see the statement on their website, it basically sounds like AO Smith is going to milk Lochinvar's name & product for all its worth.
Also, traditionally, hasn't Bradford White and Lochinvar had an association of some sort? At least as far as I know the families knew each other, and if you look at the Bradford White hot water tanks and the Lochinvar hot water tanks they shared parts and looked remarkably similar. I guess this would/could mean Bradford White and AO Smith may not be in cahootz in some respects potentially.