combustion air

[viessmann]

at minus 10 celsius or 15 what is the opinion of having combustion air piped to a condensing furnace or from the room which is obviously room temp and if you say comb air from outside will the pipe sweat and should i insulate it.thanks for any comments.

[dandyme]

what do the mfg's instructions have to say about it?

[Ingersoll AC]

what do the mfg's instructions have to say about it?

What he said

We have our high efficency pull combustion air from outside and we get way below -10 in winter. No problem with pipe sweating ect. Its un-insulated as well.

[big sky hvac]

If you're talking about combustion air for the furnace in the form of pvc attatched directly to the furnace, there is no need to insulate it. If you're drawing combustion air into a mechanical room via a 6" pipe, then yes I would insulate that for sure and probably snorkel it to slow down the rush of cold air entering the room.

[viessmann]

thanks i will pipe it in since i will change existing abs for the proper 636 pipe since somebody installed it 2 years ago that way .

[amickracing]

Going for a ride in the way back machine here...
Back when I used to install furnaces, and we ran the intake and exhaust through a roof I always cut a tee in the intake and put a plug in there.

Only a few times did I have an intake freeze up, but I was sure glad there was a tee in there and I could pull the plug and run it like that for a day or 2 until it either melted open, or it was safe to get on the roof.

If it vents out the side of the house I don't care, because you can generally get to those to beat the ice off of them.