Question on Air Vent Knockout for Gas fireplace insert

[Exmasonite]

Hey all… I have a follow up question to the same gas fireplace as my other thread but was unable to edit the title so i figured i'd start a fresh one.

So, my folks have an older Heat n Glo 6000 Natural gas fireplace insert. It's in a fake fireplace that vents out the back of the house (newer build, no true chimney that goes up).

There is a strange knockout in the underside of the fireplace that is drafting a lot of cold, cold air from the fireplace around insert. The front of the stove is open at the base and all of this cold air is drafting into the house.

I am going to have to work on getting a picture as I'm having some trouble uploading… will have to review the guidelines.

Anyway, my question is whether I can block with knockout/air vent. The stove is more than capable of drawing room air from the front and has outward ventilation so I am not worried about fumes, etc. I think this knockout would be necessary if the front of the insert was sealed and there was no place to draw air.

Obviously, i want to get some stove rated insulation. Otherwise, I think only option is to block the vent and not run the stove. The amount of draft this thing allows is terrible… cools the room by 10-15 degrees in this weather.

Thanks in advance. I will work on pics.

 

[Exmasonite]

Edit: I was able to attach picture to original post. You can see the oval hole in the sheet metal.

 

[DAKSY]

Edit: I was able to attach picture to original post. You can see the oval hole in the sheet metal.

The "Strange Knockout" you refer to is actually there to run the gas line into the valve cavity. Looks like whoever installed this unit didn't have a clue. You can block it with aluminum tape & while you're down there on your belly, look for & tape off any other holes in that area. Pretty sure the combustion air for this unit comes in thru the DV cap. I don't recall any B-vent 6000 series units ever being available...

 

[Heatsource]

Bob is right on, as usual!
if air is coming in thru the gas line knock out, then the chaise or framing enclosure is leaking/ was not sealed or insulated