Insulating stove pipe celing support box

[Mrbreeze742]

I have a Jotul F3 with a straight up through the ceiling/attic/roof chimney, sitting on a durvent brand support box. I've noticed room seems noticeably colder when stove is off and we are running on HVAC heating system, and the support box is very cold to the touch. Any Problem with putting rock wool insulation inside the air space between the sides of class a chimney and the side of the box? I am also aware I'm most likely losing heat migrating through the (uncloseable, Thanks EPA!) intake vents on the stove and up the chimney. Planning to make a plug/cover for them when stove is not being used. Thanks!

 

[Ludlow]

I insulated my Supervent support box with the approved Supervent JUSI insulation. Unless it is tested and approved by Duravent you cannot (by rights) put anything in your support box.

 

[webby3650]

I insulated my Supervent support box with the approved Supervent JUSI insulation. Unless it is tested and approved by Duravent you cannot (by rights) put anything in your support box.

The JUSI looks to just be a piece of brown fiberglass, we use them pretty often.
You are correct, unless it’s approved it shouldn’t be done. I don’t think Dura-Vent allows it unfortunately.

 

[Ludlow]

The JUSI looks to just be a piece of brown fiberglass, we use them pretty often.
You are correct, unless it’s approved it shouldn’t be done. I don’t think Dura-Vent allows it unfortunately.

Looked like rockwool to me. Didnt seem like fiberglass but could have been.

 

[snaple4]

My guess is that it uses the air to coil off the support box. If you insulate the box then you reduce its capacity to dissipate heat. Sure you want to take that kind of risk? Might do nothing to the wood holding the support box or it might slowly lower its combustion temp over time.

 

[Ludlow]

My guess is that it uses the air to coil off the support box. If you insulate the box then you reduce its capacity to dissipate heat. Sure you want to take that kind of risk? Might do nothing to the wood holding the support box or it might slowly lower its combustion temp over time.

If you removed the insulation from class A pipe, would it work better or worse as far as external pipe temps? Something to ponder.

 

[snaple4]

If you removed the insulation from class A pipe, would it work better or worse as far as external pipe temps? Something to ponder.

i see what you are thinking but I don’t think it holds. You remove insulation from class a and you effectively make it a regular double wall pipe. Your clearances just doubled or more. Also, think about the shape of the box. Heat travels along the metal. As it runs away from the pipe and then up the sides it has that whole length to shed heat before the wood supports. If you put insulation in that space then you prevent the natural rejection of heat and thus maintain a higher temp along the entire structure of the box.

I could just be over thinking this but to me it stands to reason that the dead space is for heat rejection.

 

[Mrbreeze742]

Thanks for thoughts everybody, looks like ill be keeping that air space :/