Insulation wall thimble?

Steve1213

New Member
Oct 31, 2018
5
Qc
Hi, i have a harman pellet stove im currently make my chimney set up . my question is for the wall thimble do i need to insulate inside the wall thimble where the chimney pass i have maybe 3 inch each side?

Sorry for my bad english im french :/
 

tbear853

Burning Hunk
No insulation in wall thimble.
 

Steve1213

New Member
Oct 31, 2018
5
Qc
And outside wall thimble i can insulate with any foam insulation or i need to use fire break break foam ?
 

Steve1213

New Member
Oct 31, 2018
5
Qc
Thimble is for pass combustible material why i cant have foam touch outside of the thimble ? I dont speak for inside the thimble i know i need to stay this 3" clear around the peller vent
 

PelletPractitioner

New Member
Oct 4, 2018
55
Connecticut, USA
What make and model?

I just got done installing a thimble for a straight-out vent through my wall. My pipe was rated for 1" clearance. The thimble was built such that there was a 1" air gap between the vent pipe and the thimble wall. Insulation can come in contact with the *outside* thimble wall, because I still meet the requirement for a 1" air gap.

In your case it sounds like you have a 3" requirement and the thimble provides a 3" gap between your vent pipe and the outside thimble wall. Always consult the manual, but it sounds like you would be safe insulating outside of the thimble wall (NOT the 3" area between the pipe and thimble wall).
 

Steve1213

New Member
Oct 31, 2018
5
Qc
Model is supervent model pl

I have 1.5 inch each side of the pellet vent inside the thimble i stay this clear and if i understand i can insulate the outside of thw thimble with a combustible material
 

tbear853

Burning Hunk
My "thimble" is in a 12"x12" hole cut (with a chain saw in 1992) through two levels logs, then blocked around with 2x4 for a ledge, then there is a 12x12 sheet steel in house and a matching 12x12 outside, they are 3 1/2" apart and there is a hole that came in the sheets dead center that tightly hugs the pell vent, there is also a slightly larger 3 1/2" tall tube that surrounds the pell vent between the two sheets.

A number of years ago, I used a hole saw to cut a 2" hole in top corner through both sheets, had local exhaust bender bend me a piece to fit the holes and put a 90 degree bend in it, clamped screen over inlet end and secured to a log end that was handy, that is my cold air intake. connects to stove with suitable size short piece radiator hose.

No insulation .... just air space and that extra larger tube around pell vent. In spring, I'll repaint the "thimble" and air inlet as I replace last of pell vent. That inner extra tube is same diameter as that recess around pell vent, one side was a hair smaller that other and when installed, they form one extra tube.

0 Need new flue pipe 25 years later 2.jpg
 
Last edited: