My Pilot Stays Lit but Eventually Goes Out
There are a few things that could cause your fireplace to go out while running.
For sealed Direct Vent fireplaces, blockage in venting can cause the fireplace to shut down. Birds, bats, mice, and other vermon are sometimes known to build nests inside/on top of fireplace terminations. Because the fireplace cannot expel the exhaust or cannot get enough oxygen, the flame will “starve” for air and eventually everything will go out (including the pilot light). This will happen within minutes of initially turning on the fireplace.
Here is a video that shows the “ghosting” effect of the flames that will occur before it will go out and is a definite indicator of a venting issue.
One way to verify this is to try running the fireplace for a short period of time with the glass removed or cracked open slightly. If it runs fine with the glass off or open a bit, you can defiantly determine it has an issue with the venting, most likely blockage that needs to be cleaned out.
Weak Pilot Flame
Another reason your pilot may cut out could be related to your pilot light flame. After you first turn it on, the fireplace will start to create draft as the chimney heats up. If your pilot flame is more “candle like” and less “blow torch like” you may see the draft start to affect the pilot flame as the fireplace heats up.
Good Pilot Flame:
Bad Pilot Flame:
WATCH the pilot light as the fireplace heats up. If you see the flame start to pull away from the thermocouple or thermopile sensors, these sensors will not have enough heat to keep the main control valve open, and the pilot light may go out. If it seems like this is happening, its best to replace the pilot assembly.