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Active Member
Apr 12, 2006
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I have what seems to be a thermopile in the back of a NG space heater.The 2 wires run to what seems to be a thermostat to shut off the pilot light if the heater gets too hot. I can't get the pilot light to stay lit. I've bt passed the thermopile and it works. Can I run the heater without it?
I have attached some pics to help explain. Thx. OOPS! It says my files are too big. Help!
You need to reduce your picture size using a photo program to post.

Don't run the heater without this safety feature.
Hello Cabinetsetc:
A thermopile will be located in the flame of the pilot light and will not generate enough current to open the gas valve unless the bi-metal in it is at a certain temperature. If yours is not in the flame of the pilot light it is a temperature activated High Limit switch (most likely).
The High Limit switch is there to protect you and your home; please do not by-pass it. Underwriters Laboratory has demanded it there and any modification can result in Fire, Injury or Death.
A thermostat will not shut a pilot light off, only the main burner. The pilot light should be 'standing', whether there is a call for heat or not. Take the limiter off the heater and take it to a heating supply store along with the Brand, model and serial number. They will be able to help you with it.
While the store is closed today would be a good time to get out a wire brush and vacum cleaner. Clean the little holes in the burners and the large air intake holes of the burners. Remove the pilot tube and clean it thoroughly. While we are not using our heaters in the Summer there are little spiders that find refuge in the heater and build webs, cocoons and lay eggs which mess it all up. Who knows? a good cleaning may be all it needs and doesn't cost a thing when you do it yourself.
Please post back and let us know how it works out; I wish you the very best.
I would follow Glenns advice, and post us back to see you and yours are still in one piece.:D
Good morning Glenn, Insp, & Travelover; You will be so proud of me. I didn't blow myself up or anything even remotely drastic. The switch turned out to be a cut out switch to shut the furnace off in the event of a down draft problem. Once I new what I was chasing it was easy to find the problem. It turned out to be a bad connection in one of the wires leading to the switch. Turns out thermocouples produce electricity too. Learn something every day. With my new found knowledge repairing these things will be a whole lot easier. They turned out to be less complicated than I had anticipated. Thanks for all your help.

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