Older NG Heat N Glo Won't Stay Lit - Cycles

[thompsdw]

Hello everyone. I have an older gas vented heat-n-goo standing pilot gas fireplace. Last year I changed the entire thermocouple/thermopile assembly. Worked fine until startup this year. Sometime I turn the switch on and the fireplace won't light, but sometimes it will. After running for a short time it will usually shut off and then after a while will relight. Then it will run for a longer time and shut back down. I assume the thermopile is the easy answer, but it is confusing given it is relatively new.

Any ideas to help?

 

[DAKSY]

Which switch are you using? A wall switch or the tech switch under the unit (if there is one)?
If the tech switch works perfectly & if using the wall switch is giving you problems, replace it.

 

[thompsdw]

Which switch are you using? A wall switch or the tech switch under the unit (if there is one)?
If the tech switch works perfectly & if using the wall switch is giving you problems, replace it.

I should have mentioned that. I have a wall switch. I just purchased a new millivolt switch after I noticed that the tech switch seemed to work better (but not perfect). Sorry for the omission. I could change the wires to see if that is the problem.

 

[DAKSY]

Pull the wall switch & twist the wires together.
If it works perfectly, you know it's the switch.
If it fails to keep running, the wires may be suspect.

 

[thompsdw]

Pull the wall switch & twist the wires together.
If it works perfectly, you know it's the switch.
If it fails to keep running, the wires may be suspect.

Well, it definitely stays lit on the lower control switch. I tested it last night. I will twist the wires this weekend. One question - does the switch need to be grounded? It has a grounding prong, but has never been grounded.

 

[DAKSY]

The switch does NOT require grounding. It is not an AC circuit.
It opens & closes a millivolt DC circuit.