Metal Surround/Cement board? Mark 123 Heatilator

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dcva

New Member
Sep 6, 2021
5
Richmond
I purchased my home and with it came a converted gas log set in an old 80's wood burning Mark 123 Heatilator 3138EP I recently replaced the gas logs and burner due to a slight gas leak in the pilot valve on and off switch. My question is the following. Can I install cement board over the black metal surround and attach marble? Since this is no longer a wood burning insert and the old heatilator vents are disconnected am i able to cover the bottom vent? It leaks so much cold air from the outside.

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begreen

Mooderator
Staff member
Nov 18, 2005
89,638
South Puget Sound, WA
No, they can not be covered.
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,638
South Puget Sound, WA
Blocking the vents violates the UL certification for the fireplace and may affect the cooling or clearances in other parts of the fireplace besides just the face. Also, there is no telling what the next homeowner will want to do with the fireplace. If they revert it back to woodburning it could be very dangerous. The manual specifically says, Don't Block Off the Vents.
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bholler

Chimney sweep
Staff member
Jan 14, 2014
25,564
central pa
Those vents are also required even if it is only gas logs in there
 

dcva

New Member
Sep 6, 2021
5
Richmond
Blocking the vents violates the UL certification for the fireplace and may affect the cooling or clearances in other parts of the fireplace besides just the face. Also, there is no telling what the next homeowner will want to do with the fireplace. If they revert it back to woodburning it could be very dangerous. The manual specifically says, Don't Block Off the Vents.
View attachment 281677
 

dcva

New Member
Sep 6, 2021
5
Richmond
And to be clear I’m talking about putting marble highlighted by the red lines. Not blocking any vents. The diagram in the install guide make it seem like that is okay.

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bholler

Chimney sweep
Staff member
Jan 14, 2014
25,564
central pa
And to be clear I’m talking about putting marble highlighted by the red lines. Not blocking any vents. The diagram in the install guide make it seem like that is okay.

View attachment 281682
Follow the instructions on page 16 of the manual for facing.