hello, I have a customer that called me with a Goodman 95% variable speed upflow furnace. It is in a _base_ment with 5cm pvc intake and exhaust pipe with about 3-3.5m in length. Just recently, he noticed that the intake pipe was condensating on the inside and draining down into the furnace. He has a concentric kit on the outside of the wall. The only thing I could think of was that the exhaust is getting wrapped around and coming back through the intake.

Any suggestions or help would be greatly appreciated.

All I can say is that's amazing its still running.

The concentric kit is either piped backward or its broken/not fully seated. Hope this will get you started on the problem.

That is pretty amazing, i can't believe it's still running.

That is pretty amazing, i can't believe it's still running.