Gas furnace and water heater duct and air for combustion

[Randy]

Hi, I have a new home near completion. Today I went there and saw the furnace is up and running. The gas water heater is also installed but water pipes haven't been connected. The furnace is Payne PG8J, I googled and found it here:

The water heater is 50Gal Ruud Guardian Pacemaker.

Both are sitting on a raised wood platform in the garage side by side.

The furnace has cold air return from the top (duct is in attic and return opening is at a hallway). The hot air is blown down into ductwork in the crawl space then to many registers. The furnace has other two ducts: one is obviously the flue as it is hot. This and the flue from water heater go to a Y and a thicker one goes through the roof to outside. There is another relatively large round pipe (about 8") branches from the cold air return just above the furnace. This one goes through the wall to outside. There are some wires going out of the pipe at one place and connect to a box of electronics attached to the wall. I could read some wording on it look like "fresh air damp.." so I guess the furnace will draw fresh air through this duct from outside for its combustion oxygen need. It will not use the air in the garage. But how about the water heater? It doesn't have such duct (just the flue). Do I need keep garage window open a crack to supply air for it?

By the way, do these Payne and Ruud have a good reputation?

Thanks.

R.C.

[Joseph Meehan]

OK Randy, it sounds like everything is OK. Other than I don't like equipment in the garage, I know it is common in some areas.

The outside air may be combustion air, but it sounds like it is a fresh air input to provide for some fresh air for your home that may be built very tight. If it was for combustion it would not go to the return duct.

[DN B]

Joe is correct. As for the waterheater...unless its a direct vent unit, it wont have a fresh air duct coming to it for combustion ; but, the closet is going to need combustion air for both the water heater and furnace burners -- there should be an opening ( a grille perhaps in the wall/ceiling of the closet) which will let air transfer in as its being used for combustion of these appliances. Until youre sure there is one..crack the door at least 2-3 inches. It is national code that there must be a source for combustion air intake otherwise, the burners will starve for air and 'could' start to roll out of the furnace/water heater making an unsafe situation. If in doubt, call the village inspector and register y our concern about this, then, he will come out .

[Yuban Hadd]

Hey Fuckhead, You're a hack, have always been a hack, and will forever be a hack..FOAD YA FUNDY IGNORAMUS

[Joseph Meehan]

Thanks for catching me on that one. I should have considered the possibility that they were located in an enclosed area of the garage. I was assuming the garage would not be tight enough to provide air, but even that could be wrong.

[Randy]

Hi Joe and DNB, I guess you were right. The fresh air damp duct is probably to provide fresh air to the home, not for combustion. So both the furnace and water heater would draw air for combustion from the garage. There isn't a closet for them. They are surrounded by walls on three sides but the one large side is open to the garage. The garage size is about 650 SF (2 car). Is it OK to keep the garage doors and window closed? I do have the window near the furnace but keep it crack 2"-3" would let the rain in.

R.C.

[Andy Hill]

Garage doors are far from airtight. Even with everything closed up, you'll have enough plenty of openings for the combustion air.

[Randy]

[Dan]

It's not what I'd consider an ideal installation, but under the letter of the code I'd probably have to pass it- Not what I'd design for my own house, but it's a minimum code after all- I think the garage cubic area is sufficient to supply combustion air, but I wouldn't design it that way for myself-

Dan