what does everyone do with their ash door on an exterior masonry fireplace?

[atom631]

i just did a block off plate and ceramic fiber insulation around my insert within my existing exterior masonry fireplace. the fireplace has an ash door outside that i stuffed the hell out of it with roxall. i went to light a fire and smoke started coming into the house from the air control opening in the front of the insert. i always assumed the insert was pulling in air through the air control in the front, but apparently it must take in fresh air from the back bc once i pulled the insulation out of the ash door, it started working properly again.

prior to doing the block off plate and cermaic insulation, i just had some regular insulation stuffed in the ash door with no issues. but now im wondering if i should just keep it wide open. the issue is i can stick my hand up from the ash door and into the back of the insert and my wife was able to see my hand from inside the house, looking under the insert. that just doesnt seem right to me.

just curious what everyone else does?

 

[sadpanda]

Sounds like you may have a tight house and the leaky ash door was acting as a virtual OAK /make up air vent.

Normally air sealing is good... However if you close up the ash dump the air is going to come from other weak points in the envelope (windows/doors are common) and that draft may be felt. Maybe inspect/clean flue liner/cap and verify no obstructions just in case and try again.

You could just go with it... Try putting a pipe in the opening then stuffing it full of insulation. May take a few tries to dial in the right size but having dedicated outside air on an insert is something a few of us have contemplated.

 

[Woody Stover]

I sealed up the outside ash door in the masonry chimney with some caulk.