Hi, we bought a house with an ancient furnace (29 years old), and ran the furnace with fingers crossed through our first winter here. It was loud, but ran great, no problems. Two summers ago, we had a high efficiency furnace installed, and the installers placed a furnace exhaust pipe out of the side of the basement, a couple of feet off the ground (not sure where the old exhaust was, but this was a new location as they had to cut the hole through the exterior wall). Last winter was fine, but this winter we had tons and tons of snow. Our problem this winter was massive ice-damming along the roof and evestroughs for about 5 feet on either side of the furnace exhaust pipe. So, my questions:
1. Is it reasonable to assume that the heat from the exhaust pipe may have risen up and heated the roof intermittently whenever it ran, causing this problem? (or should we look elsewhere for the problem)
2. If the answer to 1 is yes, is it possible for a complete layperson to extend the pipe out a few feet further to avoid this problem in future?
I never heard of heat rising like this to cause ice damming, the heat coming out of there is maybe equivalent to a hair dryer on "medium" setting, maybe even less. You can put your hand there and it's just a bit warm. That dissipates into the cold air quite fast.
How is the pipe layout, is the exhaust shooting straight out? That's how it should be, with the intake being a 90 down. Should be a 1/2 foot or so away from the wall too.