another pilot light thread

[primem]

I have a nat gas valor 737xn vented fire place.
The pilot will light but it won't light the main burner. The 2 times I have gotten it to light I have held the pilot on for 30 seconds. The main burner would stay on for 15minutes and then I would hear a click and the burner would shut off.

I have replaced the thermocouple and no change. What should my next step be.

tia

 

[DAKSY]

Take a reading on the thermopile.
That's the control for the burner side.
The thermocouple is for the gas flow to the Pilot side.

 

[primem]

Sorry, I,m a new to gas fireplaces. Is that the tube near the clip...part 51... It listed as the thermostat phial in the parts list?

so I unhook it from the control valve and take a voltage reading when the pilot is on?