Pilot Light Problems
This is a direct vent fireplace that works great for approx 10 minutes and then shuts down including pilot light. I tested the thermopile and thermocouple and all are with in spec. Observing the pilot when the fireplace is in the on position, the flame is blue and and distributed evenly (working perfect) and then just before the gas valve kicks out the pilot flame turns yellow and has a flame like a candle and is no longer heating either thermo. Also the pilot light works just fine if the fireplace is not turned on. Any ideas what could be wrong.
Well, since this is not a DIY site, we are limited as to what we can comment on. First of all, I'd recommend you get a qualified hearth pro in there. Have him inspect the entire installation. You did not say how you tested the TC and TP nor what readings you got so your statement that they are "in spec." is superfluous. Several of your statements lead me to believe you are not a hearth pro and with this being your first post, you would not be able to even apply for Pro status for awhile. There are sections on this site for Pros only where we can discuss such matters in detail.
I can say that such problems are often not what you think so to properly diagnose and correct them you need to think holistically:
-installed to listed instructions?
-venting properly configured, connected and maintained?
-gas supply adequate even under full load?
-MP regulator tested and no creep or improper lockup?
-readings for TC, TP, valve, wiring and switching/ stat
Sorry we cannot be of more help.
Keep the fire inside the fireplace.
Thank you for your input. I will take your advise and have a pro look at the unit. I did check the venting and cleaned with air, cleaned the entire unit as well. Thought a dirty pilot might be the problem, but since it works great until the unit is turned on, that does not seem reasonable. As for the readings of theTC and TP: TC-23.4mV and the TP 543mV open and 255mV closed. After ten minutes of running I can watch the pilot turn to a candle like flame but the flames from the burners do not change until it kicks out.