Uninsulated liner and cold hearth syndrome

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Minihoser

Member
Nov 21, 2016
6
CA
Hi,

When wood stove insert not in use it will draft back into house.

Appears I have a cold hearth issues. It happens when it is warms up outside and cooler inside and stove sitting idle. Worried about toxic gas flowing back into house.

I have a Wood stove insert with single wall corrigated liner in masonry external chimney. Liner does not appear to be insulated. Top of chimney is capped, there is no insulation around pipe or at top or bottom in chimney.

Would insulating top or bottom of chimney help with the issue. I was thinking about stuffing rock wool at top under cap and around pipe at bottom where it snakes around the flue to essentially seal top and bottom.

Any help is greatly appreciated.
Jason
 
The area where the insert is located could be a negative pressure zone. If so, insulating may not help, though by code it probably is needed. Was the chimney and smokeshelf thoroughly cleaned before the liner was put in? Can you determine if the smell is coming from the insert or from the chimney itself? If it is coming from the chimney then maybe insulation and a block-off plate would help.

Is the insert located in the basement or lowest floor of the house?
 
Hi,

House is A frame so floor to inside ceiling is 24 ft all open. Wood stove is insert approx 1.5 ft from ground. Outside chimney cap is 3-4 feet above highest part of house.

Smell is coming through wood stove insert draft holes and not from chimney itself. If I light a lighter next to draft hole I can see flame being pushed out into room and not sucked in when drafting properly. If I wait tell evening when it cools outside lighter flame will suck back into stove and draft correctly.

I've read a lot of issues happen with single wall pipe and cold external masonry chimneys cooling the liner and causing issues.

Thanks
 
It can happen but if the stove is not in use then there should be no toxic gasses. It might smell a bit tho. Mine does it in spring and fall sometimes. I usually just have a candle in it when it does it.