I have a 90%+ gas furnace that is vented with pvc pipe. We moved into a
development 6 years ago. In the 2nd year there were 4 homes on our street of
8 homes that lost their heat due to snow that blocked the intake pipes. In
all of the failed cases the intake and exhaust pipes were only 10 to 12
inches above the ground. I got the installation manual that was attached to
the return duct on our furnace and it stated that in areas of significant
snowfall the pipes (both intake and exhaust) should be extended to a height
of 12 inches above the maximum anticipated snowfall. It showed how an 90
degree elbow should be placed where the pipes exit the building and pieces
long enough to gain the necessary height placed into that elbow with another
90 degree elbow placed at the top pointing away from the building. Then a
short piece of pipe placed into those elbows. Then a reducer and a smaller
pipe was to be installed at the end of the exhaust pipe so as to create
enough back pressure to expel the exhaust gasses away from the house and the
intake pipe. The intake pipe had an additional elbow pointing down toward
the ground. Then after all that is done the exhaust should be insulated and
covered or painted to prevent UV damage.
Fortunately the hack that was installing the furnaces (108 of them) was
still working in the development and after a considerable amount of pressure
he finally extended all of the ones that were too low. I was going to take
him to small claims court and pay to have the pipes extended but what
finally got him to relent was that the pipes were a code violation. Whenever
a code says to follow the manufactures directions then those directions
become a part of the code for that particular item.
Watch for distances from windows and other exhausts. (water tank and drier
vents)
Hope this helps. Clint Stoner




wrote in message
...
I just got a call from one of my relatives. They live quite a
distance from me but I am familiar with their house because I once
lived in it. Back when I lived there, the house had a traditional
natural gas furnace that vented out the chimney. Two years ago they
had a High Efficiency furnace installed.

The furnace vents out thru the sillplate, where the two PVC pipes exit
outside. I know there are less than two courses of concrete block
showing, so that means these pipes are a maximum of 14 inches from the
lawn.

They have had extreme snow this winter and the woman has had to call
in a furnace repairman 3 times, each call costing her around $150, and
each time these pipes were buried under the snow. Each time she has
nearly frozen to death because it always happens at night and she
believes that she can not call during the night and must wait until
morning. The woman is not in good health as it is, and she is unable
to go outdoors, much less shovel snow. She has a caregiver come daily
to help her, but they dont look at things like this. Besides that,
the snow turns to a block of ice from the heat and moisture and
requires lots of chipping to clear it.

Anyhow, she knows that I am handy and have done all sorts of home
repairs. They told me she is really upset because the repair guy told
her she could get carbon monoxide poisoning, and she must dig out the
snow. She said she wishes she would have kept the old furnace that
vented out the chimney.

While I am handy, I have not dealt with these H.E. furnaces, but I do
know how they work and the way they put 2 pipes out the side of the
house for intake air and exhaust.

Immediately after the call I got to thinking about extending the pipes
higher up the house siding. I think they are too low. It would be
easy enough to use a few PVC elbows pointed upware, add 2 or 3 feet of
pipe, strap it to the house, and put some traps on top so the pipes
dont fill with rain or snow.

The question is: Is this legal and acceptable?

If not, is there another solution? Putting an awning of sorts over
the pipes might help keep some of the snow off the pipes, but there
are limits on that due to blowing and drifting.

I'm sure this happens regularly, what are the solutions?