If your fireplace doors are shut oxygen cannot reach the flames.
Gas fireplace doors open or closed for heat.
Large 10 class a metal chimney required hefty 1000 lbs of masonry firebox unsealed good radiant heat and open to the room no fans or accessory heat ducts.
This results in a dull blaze with little heat output.
Designed as a surface mount these track free doors sit outside the fireplace opening against a flat surface and help reduce.
If you close the doors the flames pull towards the glass where it can impinge and shatter the glass.
Compatible with a traditional masonry fireplace the decorative compatible with a traditional masonry fireplace the decorative and bi fold pleasant hearth ascot collection glass fireplace doors have a 1 piece welded frame and a high heat powder coated black finish.
Allowing your fireplace doors to remain open will promote better airflow.
Ceramic glass doors a masonry fireplace and do not care about any heat coming into your room then it is ok to burn a fire with your glass doors closed.
In the off chance you have.
Open no glass doors like isokern or firerock with add on gas burning unit fake ceramic logs.
All gas logs should be burned with the doors wide open even if a mfr tells you they are approved for closed doors.