Need help with several nat gas fireplaces

[DFWdude]

Howdy y'all. I have multiple gas fireplaces in my house, all in various states of malfunction. Long story short, pilot lights come on but the main burner will not. Lets get into it, and hopefully y'all can help me get them lit!

Fireplace one; foyer. Pilot comes on and stays on. New thermopile that is putting out ~600mV when in the pilot. There is NO thermocouple. With pilot lit and the thermopile heated up, if I turn on the wall switch nothing happens and the pilot stay lit. I have confirmed that the wall switch wiring is not open when the switch is tripped to "ON."

The pilot is clean and blue.

 

[DFWdude]

Fireplace two: back patio. New pilot assembly. This one has a thermocouple and thermopile. Also ~600mV out of the thermopile when in the pilot. Also like the first, when I activate the wall switch the main burner does not come on, but with this one, the pilot goes out.

The pilot is clean and blue.

Also, I did vacuum this one. The pic was taken beforehand.

Thanks!



UPDATE: having done nothing else, this one has now started working as it should.

 

[Lennox65]

Howdy y'all. I have multiple gas fireplaces in my house, all in various states of malfunction. Long story short, pilot lights come on but the main burner will not. Lets get into it, and hopefully y'all can help me get them lit!

Fireplace one; foyer. Pilot comes on and stays on. New thermopile that is putting out ~600mV when in the pilot. There is NO thermocouple. With pilot lit and the thermopile heated up, if I turn on the wall switch nothing happens and the pilot stay lit. I have confirmed that the wall switch wiring is not open when the switch is tripped to "ON."

The pilot is clean and blue.

View attachment 285200 View attachment 285201 View attachment 285202

This is a B Vent fireplace so there should be a spill switch or hi limit switch wired into the wall switch wires. The first thing that I would do is clean the contacts on the valve where T-Pile and wall switch wires attach. That rust and corrosion does not allow for a good connection.