In article , krw wrote:
On Tue, 2 Feb 2010 14:22:41 -0800 (PST), MNRebecca
wrote:

Once or twice each winter, my furnace shuts down due to a clogged air
intake pipe.
[snip]
Any advice on how I can keep the intake pipe from clogging?

It sounds like your flue is tilted back towards the house so the
condensate runs back to a low spot and freezes.

Ummmm.....no, it doesn't sound like that at all, actually. Flue != intake.