I have a high-efficiency furnace and have to change my exhaust from 2" to 3". I was sutting off in cold weather. The switch is almost done.
Two questions. Can I put a fernco (rubber gasket) fitting on the exhaust and supply for the combustion chamber? I may have to chance my A/C and coil hence the combustion intake and exhaust will need to be moved. I don't know if this is up to code or not? i.e. 2 of them per connection.
Secondly, where the PVC pipe exhaust enters the blower motor there is a black tar-like compound sealant as a seat. What is this compound / sealant? I need to redo this connection.