I want to replace an old 80% furnace that vents through the roof. But I don't need a new roof, and I'm hesitant to disturb the old shingles.
Is there a kit that lets me put a high-eff concentric vent through the old stack?
I wonder if there is a new boot/etc that would let me use the old hole. Then my furnace job would be much less complicated/expensive.
On Tuesday, January 3, 2017 at 10:57:25 AM UTC-6, snipped-for-privacy@gmail.com wrote :
on't need a new roof, and I'm hesitant to disturb the old shingles.
hen my furnace job would be much less complicated/expensive.
After searching around a bit, it seems like the concentric vent kit can go into the old roof stack. I assume that dropping the vent pipe out will leav e a pipe sticking out of the roof (in other words, assuming that the pipe c onnected to the furnace is inside the pipe sticking out of the roof, and th at once the inner pipe is removed the stack remains).
The 95% HE furnaces I've seen do not use the old Type B vent pipe, replacing it with a pair of smaller PVC pipes. Those were routed to the side of the house - I assume the exhaust is run that way for condensation management. The inlet could be vertical, but it's easier to run the PVC pipes as a pair.
On a number of occasions we have run our new pvc flue up thru the old metal flue pipe. We made a fitting that fit on top of the old flue, but I believe there's now something commercially available for doing that.
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