I have it set on standing pilot, which stays lit. The unit is only 2 years old and was working fine a few weeks ago. Temperature outside is above 50 degrees, and our main gas hot air heat is working fine. No soot build up around thermocouple which was my first guess. The remote control does not seem to be sending out any signal when this is happening either. The fire seems to go out at random times, sometimes after 15 seconds or less, or after several minutes, but will come back on after less than a minute later usually. Any other ideas?
I took 6 years for my unit to start acting up, this is what I did. Remove the log set and with a small wire brush clean the flame sensor loop or post just to the right of the pilot, the powdery residue impedes the sensors ability to detect a full flame and so the unit shuts down as a safety feature. Brush the sensor post or loop until you see bare metal , it doesn't take much to clean it. Brush the burner ports in the area a little to remove any deposits as well. Test it to make sure it lights and holds, when it cools put the log set back.