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