High Efficiency Furnace Vent Question

**Chris Stichter** · 11-03-2016, 12:22 PM

Are there any requirements for the vents to have caps or elbows installed to keep rain out? I can see moisture staining in the cabinet from the air intake. Assuming you wouldn't want rain getting into the exhaust vent either! Thanks for your help!

ScreenHunter_117 Nov. 03 11.58.jpg

Similar Threads:

**Grant Medich** · 11-03-2016, 02:56 PM

I have never seen high efficiency vents located through the roof like that.

Regarding the lack of a suitable boot in the photo, what is the substance used to weatherproof the vents? It looks like plasticine modelling clay.

**Jeff Euriech** · 11-03-2016, 03:30 PM

On a Goodman Condensing furnace, they say that the combustion air supply pipe should be pitched slightly downward at the inlet to prevent water from entering the pipe. (the diagram has what appears to be an elbow on the end of it)

There is nothing on the exhaust pipe. It just shoots straight up into the air. (it looks like there may be tubing running from the base of the vent pipe to a condensation pipe or drain)

Jeff

**Bob Harper** · 11-03-2016, 03:40 PM

rain down exhaust would drain through secondary HX drain. Intake usually does a candy cane to shield when vertically oriented. Some codes require larger diameter once outside to prevent ice plugs. See listed instructions and local codes.

**Chris Stichter** · 11-03-2016, 04:31 PM

Originally Posted by Grant Medich

I have never seen high efficiency vents located through the roof like that.

Regarding the lack of a suitable boot in the photo, what is the substance used to weatherproof the vents? It looks like plasticine modelling clay.

Pretty standard in this part of the country when furnaces are installed in the attic space. There is a boot installed where the pipes pass through the roof and it's finished off with mortar around the tile. Sounds odd, I know.

**Mark Reinmiller** · 11-03-2016, 06:59 PM

I don't see many venting though a roof, but from what I recall they typically have an elbow. I believe you would have to refer to manufacturer's requirements to for the answer.

**Jim Robinson** · 11-04-2016, 07:17 AM

Mark and the others are correct. Check the manufacturer's instructions, and it will almost always say to have the intake protected with an elbow down, like a candy cane. The exhaust should stay straight up so the condensate doesn't drip onto the roof. Make sure to check that they didn't get them switched, which can cause problems. Two weeks ago I had a concentric vent that got switched, and was causing lots of corrosion inside the furnace for obvious reasons.