Vent free wont stay lit

[javelinman]

I have a Vent free set in my fireplace, I still leave the flue open just a crack as a safeguard. My set has'nt been working... The pilot will remain lit, although when I crank up the flame, the set shuts down in a few seconds. Is this a problem with the thermocouple? Can I repair it myself? Could have used it the other night when the power went out!!!
Any suggestions???

[Phelps]

Thermocouples normally are not the issue if the pilot stays lit. This sound like either an issue of the main gas diverting away all pilot gas or there is some other safety switch involved like a flame sensor or flame roll out sensor that is triggering off, that is shutting off the whole thing. I am pulling at straws though as I don't know your unit. It COULD be the thermocouple if the flame contacting it is already borderline, and then when the main gas is turned on, somehow the pilot flame stops contacting the thermocouple a swell. Take a close look.

[lonestarheir]

Sounds more like a high temp switch somewhere. I doubt it is the thermocouple. They are to make sure that the pilot is lit and that is about it.