Help! Cold air seeping in

[Hammer44]

Hi,

I have a zero clearance wood burning fireplace and cold air is coming in from the bottom of the fireplace (cleanout box). Now, i don't mean a little cold air is coming in, i mean a lot. Enough cold air that it's noticeable. Anyone have any thoughts/ideas/solutions or things i need to investigate? I don't know much about fireplaces as i never had them growing up as a kid. I've attached a picture of the setup. On either side of the fireplace the doors open and on the right side is where you control the heat and there's a chain that opens and closes the damper. Again, i'm new to this so any help is greatly appreciated.

Thanks in advance.

 

[begreen]

Look outside on the wall behind the fireplace. See if there is a cold air intake for the fireplace. If yes, see if there is a flapper valve in it that has gotten stuck in the open position.

 

[Hammer44]

Look outside on the wall behind the fireplace. See if there is a cold air intake for the fireplace. If yes, see if there is a flapper valve in it that has gotten stuck in the open position.

Thanks Begreen
I did some more digging on the unit and i found out the outside air control door looks to not be closed properly. From what i could see there looks to be a seal that's gone/damaged and the door itself wont close properly. I can see the vent outside but i'll inspect later today to see if it's stuck. If it isnt stuck, am i able to block that vent so air doesn't blow up the vent?

 

[begreen]

If it isnt stuck, am i able to block that vent so air doesn't blow up the vent?

It may be necessary, especially if the house is well sealed. Block it off temporarily as a test, but don't burn with it blocked.

 

[Hammer44]

It may be necessary, especially if the house is well sealed. Block it off temporarily as a test, but don't burn with it blocked.

Can i burn with the vent blocked, even if i have the outside air control door closed?

 

[webby3650]

I've never seen an outside air vent that had a flapper. Typically it's just a screen, looks like a dryer vent but no flap. The outside air should be going straight up the flue if it was the problem anyway. Maybe some radiant cold, but not cold pouring into the room.

Almost always the problem is that the builder did not insulate the chase around the fireplace or install a draft stop at the ceiling of the chase. I almost guarantee this is the issue.

 

[madison]

Nice picture, great room and fireplace.

I agree with webby regarding the lack of insulation, it is in one of those spots that the builder knows is impossible to check.

Off topic, I personally would be a little concerned for the stockings hanging down that close to the fireplace.