Harman 52i Insert Outdoor Air Question


New Member
Dec 8, 2018
Hi all, I will be having a 52i insert installed within the next couple of weeks. Question regarding outdoor air.

My existing fireplace was built with an outdoor air inlet - basically a "brick vent" that I believe opens into the ash dump chute. You can't see an opening in the firebox, but you can feel cold air coming in through the chute. If I remove the metal grate from the chute, that opening is flush with the floor of the firebox, just inside the hearth opening. When the Harman is put in place, will the bottom of the insert be sitting directly on the firebox floor, or are there mounting rails along the perimeter that stand it up an inch or so? Or better yet, is the bottom of the insert not a solid piece of steel?

I'm figuring that if that chute opening isn't blocked by the insert frame, the unit should end up drawing its combustion air through the existing path.


Minister of Fire
Dec 12, 2011
South of Boston MA
Run a proper “pipe” up with your exhaust. No thinking about it being right or not. No draft, no fuss!