I’m purchasing a cabin in Big Bear, CA and got a notice from my local gas company that my water heater is incorrectly vented. The water heater is located in an attached shed, the vent pipe is B-vent that passes thru the roof of the shed to the outside and terminates directly below an operable 2nd story window, thus the noted violation. To fix the violation I need to extend the vent stack up and past the roof line, no big problem.
My question is this, since this is outside the cabin, do I need to continue with the very expensive B-vent piping, or can I transition to a single wall vent pipe since it is now outdoors? At no place will the pipe come into contact with combustible structure, it will be supported with metal standoffs.
Dave
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>>My question is this, since
>>My question is this, since this is outside the cabin, do I need to continue with the very expensive B-vent piping, or can I transition to a single wall vent pipe since it is now outdoors? At no place will the pipe come into contact with combustible structure, it will be supported with metal standoffs.
What are winters like in Big Bear?
The exposed vent will lose heat, and if it losses too much, the acidic water vapor in the flue gases will condences and run back down the flue and possibly damage the flue and/or water heater.
So B vent would be less likely to have that problem, but if it doesn't get cold much....
Continue with B vent
or replace the heater with a direct vent unit and go out the sidewall of the shed.
Because of the likelihood of excessive condensation, codes limit the use of single-wall outdoor vents to places where the 99% outdoor winter design temperature is 32 degrees or higher.
Big Bear is considerably colder than that. (I can't find the 99% temp, but I found info saying the average low for January is about 21 degrees, and that freezing temps have occured every month of the year.)
Even B-vents can condense too much if the exposed length is too great, and the cold is too severe.
You'd best check with the Gas Co. or local bldg department for local info.