I have a DV gas fireplace that has an intermittent flame problem. At times when it is turned on the manifold lights but the flame begins to float, and only burn in areas that I believe to have proper air for combustion. Within 45 seconds all flame is out and the thermal couple shuts off the pilot. The fireplace worked fine when it was new but in the last few years the problem began to happen more frequently. Now it's about 50% of the time and normally after a weather change. I've trouble shot this as a air flow issue.
If I turn off the fireplace and remove the glass I can feel cold air at the exhaust opening in the firebox with a slightly positive pressure. I've set the pilot to high to hopefully keep the exhaust insert warm enough for a draft ( the glass is very warm) to no avail. I've removed the liner to check for obstructions or other issues (two 3 inch liners). No problems were found so I reinstalled them.
Is it possible to have the draft reversed (in through exhaust out through intake) by wind/cold pressure and have it sustained even with a pilot burning?
I just dropped $100 for a service guy who just scratched his head. It worked fine for him and he has never seen a problem like this. Whats my next step? Thanx