View Full Version : Sealing up draft from Gas Boiler vent.

Clarence Martinn
12-10-2017, 10:57 AM
Not sure what it is called, but when they installed the new Lennox gas Boiler, they had to cut out a large square opening in the side of the house for where the boiler exhausts out of the house. Interesting thing about this setup, is that just before the opening in the outside wall, they have some sort of electric blower motor to vent the air to the outside. Never had that on the old Dunkirk Boiler. Well, I went in the Basement to check things out. They did a great job on the piping , but when I put my hand up to the square opening in the basement where the pipe goes out, I could definitely feel a cold draft around the right side of it.

What is the best way to insulate that ? It looks like there is some sort of automatic damper that opens up when the blower motor near that opening starts up

Jim Becker
12-10-2017, 11:05 AM
You likely need to use a fire rated packing of some sort to seal around the hot vent pipe for drafts. Consult your HVAC folks to confirm as they should know the local regulations