How to block flue with pellet insert

[BucksWhit]

I moved into a house with an old Whitfield insert. Manual light manual everything but we like it. Thanks to help on here it runs like a clock!

I was moving it for a cleaning and noticed the that the flue has ~ a 4 inch pipe going up it for the exhaust. Around the pipe is a massive opening where I can feel cold air coming down the chimney. Large brick chimney.

How hot does that pipe get? Could I use regular fiberglass insulation? Ceramic blanket?

 

[Mt Bob]

I moved into a house with an old Whitfield insert. Manual light manual everything but we like it. Thanks to help on here it runs like a clock!

I was moving it for a cleaning and noticed the that the flue has ~ a 4 inch pipe going up it for the exhaust. Around the pipe is a massive opening where I can feel cold air coming down the chimney. Large brick chimney.

How hot does that pipe get? Could I use regular fiberglass insulation? Ceramic blanket?

You can,not recommended,for health reasons.Proper way is a steel plate,with small opening,sealer,but,rockwool(look it up,comes in different versions)works well,and safe
Pipe prob never over 200 degrees,if proper pellet pipe.

 

[BucksWhit]

You can,not recommended,for health reasons.Proper way is a steel plate,with small opening,sealer,but,rockwool(look it up,comes in different versions)works well,and safe
Pipe prob never over 200 degrees,if proper pellet pipe.

Thanks!! Good point you do not want the fibers potentially blowing into the house. Rockwool might be my answer! I looked up the steel plate. Looks like something I would need to fabricate over the summer when not burning.

Others have good luck with rockwool?

 

[railfanron]

Rockwool would be fine. I used ceramic wool as I had some laying around. Fiberglass would also work but it would take a lot more to effectively seal the opening because the binder will possibly burn off the fiberglass so a much higher thickness would be needed. If you did use fiberglass make sure it doesn't have any vapor barrier (flammable paper or foil) on it.
Ron