Big Pilot

Big Pilot

Our new house has a gas fireplace, and the pilot light is always on but sometimes the main flame won't turn on

It's a gas fireplace, not sure what brand. It's presumably as old as the house, about 13 years. It's got a big pilot light that stays lit with no problems. The main flames sometimes will cut off randomly (leaving the pilot on), and other times the lightswitch style switch won't be able to activate the flames at all. What do I do? Is there fireplace service people or what? I'm pretty handy, but working around possibly deadly gas is kinda intimidating.

Any ideas would be great. Thanks!

Arrgh. I hate gas fireplaces.

Pound for pound the worst heating devices on the market.

Pretty, yeah sure, but a terrible heaters.

Rant over... sorry.

Gas fireplaces typically use a thermocouple to keep the pilot lit. However, a thermoPILE is usually used to run the control circuits and the burner.

A thermopile generates about 300 milivolts to operate your heater. This low voltage can be interrupted in its circuit by very low resistances. Resistances that wouldn't affect a 24vac control circuit will stop a milivolt signal.

Is your thermostat 24vac rated or milivolt rated? 24vac t-stats will work... 'till they don't anymore.

The 'on/off' switches and safety switches (flame roll out) are also typically (and moronically) 24vac rated from the mfg. They could be performing poorly.

Even a slightly loose spade connection could be the culprit.

The thermopile itself may becoming weak and unable to generate sufficient voltage, or the pilot flame isn't directed enough on the thermopile.

Possible, but least likely, your gas valve might be bad. That would be a real bummer.

Advanced DYIer project at best. Why? Because:

1) No two gas fireplaces are designed the same, even those of the same manufacture. Even good instructions will be hit and miss.

2) Burner arrangements are different and disassembly/ reassembly can be a nightmare.

3) Lastly, the scumbag manufacturers sometime use specific (and more expensive) thermopiles AND thermocouples not available off-the-shelf at the hardware store.

You could jumper components in the control circuit to identify a bad actor IF, and only IF, you are able to distinguish the burner control circuits from a 120 volt blower circuit.

Otherwise, time to call a serviceman. Specifically, one with extensive experience or who specializes in gas fireplaces.

Good luck.

IWC Schaffhausen - Big Pilot