MUNCHKIN

Tim Doran_4

Several people from HTP promoted the use of the boost feature and/or changes to the software to increase output when things were a little short.

Tim D.

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bob young

MUNCHKIN

I saw a commercial installation today where two munchkin boilers were used in conjunction with heating coils and a hot air system. all direct venting with pvc pipe. is this considered a practical application. I am not familiar with this boiler so appreciate any & all comments. i have to put a gas test on piping but am not responsible for installation and wish to know if it is a normal accepted installation .

tim smith

Normal? acceptable, yes

Bob, it will work fine for the application as long as the water temps required are not up over 180 at od design would be my guess. Make sure you size your gas line plenty large enough as these boilers do not like much pressure drop at all. Just FYI. Also make sure the sparky has provided a good ground source. Good luck, Tim

Ken_40

Huh?

The gas valve used by Munchkin is among the "most tolerant" on earth regarding gas pressure.

The water temperature has little to do with whether PVC is a good choice. The manufacturer specifies PVC pipe as the pipe that must be used in venting.

No need to guess; it's all in the installation manual, easily accessed from their website.

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Brad White

Agreed that

the unfortunately named Dungs gas valve is very tolerant of low gas pressures. It is the gas valve installed on the Hydrotherm KN line and is a feature we appreciate when specifying them in certain parts of Boston where 4.5 inches WC is all the gas company will guarantee.

The water temperature though, does have an impact on venting material insofar as there is a direct relationship between the water temperatures and the flue gas temperature.

Do I understand that HTP no longer has their boost feature (where the M80 boosted to 110 MBH during domestic water production)? What was explained to me is that this feature was mis-used in the field to gain higher capacities and temperatures, (I assume for fan coil units or to buy a smaller boiler, I do not know...). Anyway, the offshoot of that practice was damage to the venting systems when the flue gasses overshot temperature for too long a time.

CPVC gives you a better margin, but as you say, Ken, follow the manufacturer's instructions and you cannot yourself be blamed. But we are not robots' one does have to ask the questions.

bob young

fresh air

Brad, when using sealed combustion equipment, what are the guidelines for incoming fresh make up air for the boiler room. i mean in addition to the specified required piping connected directly to the units. thanks

Brad White

Open to Interpretation, Bob

Depends on what your local (state) gas code dictates and how that is interpreted. I think the codes are coming to grips with the realities of sealed combustion. It also depends on how isolated the boiler room is or how tight and confined, as a matter of good design practice.

I have had some jurisdictions that recognize and reference it, require the full NFPA-54/ANSI-Z223.1 (National Fuel Gas Code) combustion air provisions regardless. I have not seen the new IMC yet (not yet adopted here in MA that I know of).

The issue as I had it explained to me is because of a gas leak there would still be a path for the gas to be vented out and outside air to replace it. Of course, if commercial work the gas trains are vented separately to atmosphere anyway.

Other jurisdictions say that sealed combustion negates the need for separate combustion air but there is the issue of general cooling and ventilation for a habitable space. (Here in MA, all spaces are habitable, even mechanical rooms.)

Personally and if the local AHJ allows, in a house I would not add specific provisions if the boiler or furnace had sealed combustion and all the safeties and if the house was not super-tight. To do so would defeat a key benefit to any sealed combustion appliance. In a super-tight house I would want at least some air supplied there for cooling and ventilation if nothing else.

My $0.02

bob young

thanks much Brad

bob young

tim & ken thank you gentlemen

Ted_9

PVC, CPVC and ABS

These are approved venting materials by the manufacturer HTP.

Unknown

Ted

PVC and ABS are only approved in the eyes of the manufacturer of the heating equipment as specified in their manual. They are neither tested nor approved by the pipe and fitting manufacturers or their governing agencies. Canada has taken a stance on this issue and states that the material used for venting applications of heating equipment must be an "Approved Venting System". As far as I am aware there is only one PVC manufacturer that has an approved "system" and I don't believe they do business here yet. Coaxial Polypropylene and AL29-4C are the only available "Vent Systems" that are available in this country at this point in time. It is for these reasons that we took a stance and allow only approved "vent systems" such as Polypropylene and AL29-4C as venting materials on our Freedom and CHG series of condensing boilers.

Glenn Stanton

Manager of Technical Development

Burnham Hydronics

U.S. Boiler Co., Inc.

Ted_9

cpvc

I think cpvc ULC-S636 is approved for vent temps at 194 degrees.

I also think that Ipex is the one that manufactuers the pvc rated for higher temps.

tim smith

gas press. etc.

Ken, maybe the Dungs valve is tollerant but depending on what version of Munchkin they have will determine what gas pressure they should run at. Tim

Ken_40

Glenn brings up an interesting point.

I wonder if the makers of clay liner material we buy at most cinder-bock manufacturers have any approvals? Then too, I wonder if single wall galvanized smoke pipe has any certifications?

I wonder if the sub who casts the collar that adapts from the boiler to the vent has formal certifications? I wonder too if the makers of the steel pipe that goes from the block to the pumps is certified; and if so, by whom?

I suspect Glenn has erred on the side of safety. However, if the manufacturer says to use PVC for venting I suspect lots of lawyers would be richer than they are already - were that a real issue.

Glenn, could you draw the liability line regarding who's liable for what, and upon what "logic" that line could be legally defended or challenged?

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Ken_40

The local utility in NJ

foremrly known as ETG (Elizabethtown Gas) frequently ran under 4" w.c. during high demand days. Many systems would have pilot outages, especially around 6 a.m., when everyone's day/night 'stat kicked in. The Munchkins never has a problem. Just about everything else did.

I persoanlly have seen 3.6" w.c. at the meter (and no load on it - dials "still")

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Unknown

Ken

I made no mention of "liability" or "legalities" in my post to Ted. I just stated the fact that PVC pipe and fittings are not tested nor approved for use in venting gas combustion byproducts. There are pipe and fitting manufacturers that have also come forward with statements to the such. If there were not possible safety concerns then why haven't the pipe and fitting manufacturers come forward to have their products tested and rated as such. As Ted mentioned, Ipex does have an approval on their products. We market many boilers in Canada and chose to stay with their lead on this issue.

Glenn Stanton

Manager of Technical Development

Burnham Hydronics

U.S. Boiler Co., Inc.