On Thu, Oct 8, 2009 at 7:53 AM, David Huss <dave@customrefrigeration.com> wrote:

I currently have 80,000 btuh (output) 80% sealed combustion furnace and a 40 gallon natural vent water heater. My old chimney vent is 5 or 6" not sure (I'm not at home).
My furnace is vented as per instructions with PVC pipe with proper pitch and termination fitting outside (20' away from furnace) and the water heater is vented up the old stack.
Due to recent home addition I would like to move my furnace vent to the old stack with the water heater. My plan is to leave the air intake where it is but move the exhaust.
The water heater is about 7' away from the old stack and the furnace is within 3'.
If the suggestion involves joining the two vents how do I transition from PVC to vent pipe??
Any ideas would be helpful.

Thanks, Dave

[Jeffrey Moore]

Dave,
This won't help you much but I don't believe that a 80% furnace uses a PVC vent piping, as the temperatures of the exhaust gases are too high. The 90%+ furnaces can use it though.
As to the your original question one of the more advanced HVAC type guys may chime in to help out.