On Dec 16, 9:11*am, "Jim" nospam@wherever wrote:
* * *Hello,

* * * *I just had the furnace guy refire up my energy efficient furnace as
it went out last night. We have been having a cool spell (-45 to -50
Celciuse) in Canada here... I have a 2600 sq ft four level split home and
they installed the new furnace last year and I have these three inch plastic
pipes as an intake and exhaust. Problem is the exhaust had to be run for
quite a ways (through the garage and up through the roof) for the
installation and the very top of the exaust is freezing over (The exhaust is
sloped properly and condensation does drain back) The part of the exhaust is
the verticle section coming up through the roof...The verticle section rises
about 5 feet over the roof so that it won't be buried in a snow
bank........This morning we cut two feet of length as the end of it iced
over and closed the exhaust. I don't know weather to use heat tape on these
three inch lines or just wrap with insulation.... Thoughts...typing with
gloves on here...just got things up and running again...close call...laying
in bed this morning and our cat came to bed and noticed he was cool to the
touch...LOL...lucky I didn't freeze any pipes Thanks..... Jim

Where is the Pvc intake, Its common here to run both intake and
exhaust pipe out the same general area with about a 2ft inbetween the
intake and exhaust, mine is that way and my Lennox pvc flange has 2
holes mine is about 3ft above grade. The longer the run the more
problems you can encounter, your instal manual specifies how many feet
and how many elbows you can have and maybe at a certain outside temp,
did you follow it. Cant you run out the exhaust near where the intake
is. -50 is cool, so what is cold up there.