My Tempstar high efficiency furnace has water draining down the air intake pvc, and into the furnace all over the burner and gas valve etc. Furnace is 6 years old, but I never noticed this problem before.

The intake and exhaust are both vertical up through the roof 2" pvc. They are 6ft long between furnace and roof, and 2 ft outside above roof. Intake has 2 elbows and points back down toward roof. Pipes are 20" apart with exhaust 6" higher than intake. In 10 degree and colder weather, I get some icicles forming out of intake opening.

I'm wondering if warmth from the furnace could be rising up and causing condensation to freeze? Both pipes are in a heated space until they pass through the roof.

The inducer motor was replaced last week due to pressure switch shutdowns. But this was during a below zero sustained temp cold snap, and I'm wondering if the intake could have been iced closed? Temps were above freezing a couple days, so I'm guessing it all thawed out, but now we are going below zero again, and I am worried it will ice up again and damage my new inducer.

Has anyone had this happen? Should I try insulating the pipe up to the roof?

Any suggestions are appreciated!

Larry in frigid northern Wi.