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
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?
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.
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 .
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.
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.
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-
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