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
(said the repair guy after traveling out in a blizzard on Sunday
morning the first time it happened). If I disconnect the pipe from
the furnace and let it draw air from the room instead (which I'm told,
by the repair guy, is harmless),

He's right. It's less energy-efficient, because cold air is drawn into the
house to make up for it, but it won't harm anything (other than your bank
balance).

it fires back up and runs fine. But
I hate the idea that, each year, I have to live in dread of the time
I'll wake up in the middle of the night to a disturbingly cold house
and then have to live with a furnace drawing air from a basement room
instead of outside (until temps outside climb above freezing, which
can be weeks).

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.

(You sure you don't have that backwards?) That's probably most of the problem
right the the pipes face the wrong directions. The intake should face DOWN
so that rain and snow can't get into it. And the exhaust should face east, not
west: in most of North America, the wind comes from the west much more
frequently than from the east. You want the exhaust to be moving in the same
direction as the wind, not into the wind.

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