Venting for propane gas water heater?


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Old 11-24-14, 06:44 PM
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Venting for propane gas water heater?

Hi,

I am switching propane supply companies, and in the process I learned that the venting for my water heater was not up to code. So I'm wondering if anyone can tell me something about the requirements for making this meet code. I spoke to my building inspector about it, but I missed a critical piece of information and probably gave him an incorrect picture of the situation.

Currently, the gas heater vents horizontally out a concrete basement wall. The clearance to wood is 16" above the vent, roughly 4-5' beneath the vent. The piece I missed is that to the side of the vent, about 8" away, is where the concrete wall drops from full height to a half wall, meaning that there is wood 8" from the vent. This vent is 3" diameter single wall vent pipe, not the B-type double wall stuff. It exits the basement and takes a 90 turn upward for another 3 feet before ending with a cap.

The inspector said that as long as the clearance to wood is 12" or more then single wall vent pipe is OK. He said I'd be able to extend the pipe up to the right height above the roofline and I'd be all set. So that was my plan before I noticed the side clearance wasn't met.

Questions:
- do I need double wall B pipe with the small clearance?
- if I need to put in double wall pipe, could I go straight up then horizontal through the rim joist, then upwards above the vent pipe? (This would be easier than cutting another hole in the concrete wall.)

Any other thoughts? FWIW, I have considered a power vent, but do not have electric service near where the water heater is, so that would require bringing in an electrician but would solve the venting issue. It's more $ but ultimately a better solution, but I'm looking to keep cost down right now.

Thanks,
Jeff
 
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Old 11-24-14, 08:11 PM
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The pros will need to address the clearance issues, but a question from another specialty, how old is your current water heater. I believe efficiency codes are changing to where water heaters will need to be significantly more efficient. I can dig up the recent discussion about this if needed, but, if memory serves me, I believe heat pump water heaters were the only option to meet the new efficiency level. How far out this is I do not recall.

Bud
 
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Old 11-25-14, 09:26 AM
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How long a run is the vent? It may be easier to simply replace it with B-vent.

You need to keep B-vent at least 1" away from combustibles. That would require a pretty large hole in your rim joist. Is there anything wrong with following the same path as your current vent?
 
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Old 11-29-14, 01:35 PM
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Thanks. As for the efficiency question, I asked our code enforcement guy "is there anything else I ought to know about this, anything odd that I might not see coming?" to which he replied negatively. So I'm thinking just a standard heater is OK here.

The vent run is only a few feet. The heater is right up against a poured concrete wall. The vent runs through the concrete and is concreted in place, with the nearest combustible about 8" away on the side.

So the problems with using the same path would be 1) it'll be an eyesore running pipe exterior up above the roofline (true regardless of the type of pipe), 2) getting the old vent out, and 3, enlarging the hole to accommodate thicker pipe. It's all manageable, just a bit of a pain. Still, it's probably a better option than punching a large hole in the rim.
 
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Old 11-29-14, 02:14 PM
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Dumb question here, do you need to enlarge the hole? Since it is in concrete can the b-vent terminate at the concrete and then start again on the outside. Maybe that does not satisfy the clearance issues. Just asking.

Bud
 
 

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