In article ,
MNRebecca wrote:
Once or twice each winter, my furnace shuts down due to a clogged air
intake pipe. The pipe clogs in subzero weather or during/after a
blizzard, presumably because of snow/ice building up inside the pipe
[ ... ]

The intake and exhaust pipes (white plastic PVC pipes) vent to the
outside right next to each other, just a few inches apart, about 2.5
feet above the ground. Each bends 90 degrees in opposite
directions...the intake faces east and the exhaust faces west.

Any advice on how I can keep the intake pipe from clogging? Thanks so
much if you can help.

Cheap possible fix: Get an elbow that can be attached to your intake
pipe outside the house, pointing it down. That will keep snow, sleet,
hail, etc. from getting in. No need to glue it, just slide it on. If
it's loose and tends to fall off, secure it with a stainless steel
screw through the top, or drill a small hole through and drop in a
galvanized nail.

I really doubt that you have a condensation problem, as winter air is
generally very dry and wouldn't condense going into a warmer environment.
If, however, you're getting condensation from somewhere, you could
disconnect it from the furnace, cut a slot into that end an inch or so
longer than the flange on the furnace, and feed a heat tape through the
pipe to the outside. Use the slot to bring it out at the furnace, and
seal the slot with furnace tape.

The intake should slope down from the furnace end to the outside;
otherwise condensate would flow into your furnace, which would not
be good for it. (This could be a concern in warm weather, unless the
furnace blocks inlet/flue airflow when it's not running.)

If possible, adding a few feet of exhaust stack with an elbow and a
rain cap will help your furnace avoid pulling exhaust back into the
intake.


Gary

--
Gary Heston http://www.thebreastcancersite.com/

"It's kind of hard to rally 'round a math class."
Paul "Bear" Bryant