Need an insulation solution between an exterior wall and the stove's double walled pipe, venting str

[Augmister]

I installed my second pellet stove to vent straight out through the wall behind the stove. I made sure I pulled the wall insulation 3" away from the vent pipe going through the wall. I have a nice draft coming in around this pipe, into the room, and need a high temp flexible material (I have about a 1/4" gap from the pipe to the exterior wall) to plug the gap. I would rather not use the high temp red goop and if there is a better solution, please post. Thanks!

 

[woodsman23]

did you use a wall thimble?.. It is a must. The pipe does not get very hot why not just use some expanding foam??

 

[jtp10181]

Most pellet pipe only needs 1" clearance in the USA. Use a wall thimble and black silicone caulk to seal the gaps. Seal the outside will with clear silicone so you don't get soot leaking back in also.

 

[Augmister]

Most pellet pipe only needs 1" clearance in the USA. Use a wall thimble and black silicone caulk to seal the gaps. Seal the outside will with clear silicone so you don't get soot leaking back in also.

Canada requires 3" so I thought I would error on the side of goodness.... This is not so much the problem as the gap between the outside of the vent pipe and the gap between the interior and exterior wall.

I did use a wall thimble (still have a small gap) but concerned about pipe temp. Is black silicone caulk higher temp? You are telling me it is OK to use silicone caulk around the outside of the vent pipe, between the pipe and the opening through the exterior wall of my house to cut the draft? I just want to make sure I understand your recommendation. Damn cold here in the NE... 10 - 19 degrees at night and big snow for tomorrow night....

 

[krooser]

Red sealant has a higher temp rating than black although the black would work fine to seal between the thimble and the vent pipe. The vent, if it's double walled, shouldn't hit over 140F or so...

 

[jtp10181]

Yes the black silicone is fine.

 

[Augmister]

Thanks to all for your help!