Background: Heat & Glo Escape 42DV natural gas fireplace shuts off after 2-3 minutes. Will not relight immediately following shut down. After an hour or so, it will relight and then extinguish again after the same 2-3 minutes. The pilot light works fine, sparking and then lighting with each attempt. Symptoms are exactly the same whether the glass is installed or removed. Over the course of a month+ of troubleshooting, the fireplace has lit and stayed lit for a few hours (until I turned it off) just twice. The other ~30 times, it behaves as described above. We've owned the home for a year and the issue has been persistent the entire time.
Troubleshooting already completed:
- Gas line from valve to main burners cleared out with air compressor
- IPI (ignition/thermocouple/pilot light) assembly replaced
- Control module replaced
- Gas valve replaced. The replacement valve came with a manual rheostat for high-low which can be removed and replaced with the electronic rheostat that presumably gets it's signal from the wall-mounted control panel switch for high or low. I attempted using the manual rheostat first before replacing it with the electronic one, but the symptoms remained exactly the same.
I'm running out of ideas. My next guess would be the gas line itself has low pressure (we're at 7,000 foot altitude, so it's supposed to be higher). I have another fireplace in the basement and it has no issues starting or remaining lit....though the flames don't look particularly big and bright orange. There are no other 'low pressure' indications in the home (furnaces, water heaters and kitchen burners work great). I have not measured the pressure at the valve as I don't currently own the proper equipment.
Anybody got any idea of where I should look next?
Thanks in advance.