We have an approximately 10 year old Healitator fireplace with an IPI ignition. Starting this fall it was a bear to get started. It's on a thermostat (Aube). If the fireplace has not been used for more than say 5-6 hours it's very difficult to get going, but once going (warmed up) it fires right up as the thermostat turns it off and on as the temp in the room fluctuates. I had a technician out yesterday that found the burner had some debris from fake logs (metal bracket flaked off) causing some interference. He cleaned everything up (logs, glass, sensor, etc), tested gas pressure, did a bunch of electrical and voltage checks, observed the burner light up (no apparent clogs etc), and put everything back together and at the time the fireplace would fire right up within two seconds each time. Now after it was off overnight, it's back to struggling to start if it's not been used for several hours.

Setting the temp in the thermostat I'll hear the thermostat click on, and in the fireplace I'll hear 3-4 clicks (sparks) of the ignitor, but nothing happens. I'll have to turn the thermostat down than back into range again and the fireplace does the same 3-4 clicks and nothing. After doing this a few times it will finally start. Since the cleaning it's gone form having to do this cycle say 8+ times, to maybe twice, so it's better but still an issue. While warm start/stop is just fine, it's not until it cools down that it's a struggle again. Any ideas? I'll call him to come back, but what else would he check/do?