I'm troubleshooting a gas (propane) fireplace. The pilot won't stay lit (after I ignite it with piezo start and let it burn 30-60 secs. I pulled the unit out to have a better look, and then decided to try again to light the pilot - this time it worked.
Here is a picture of the pilot assembly, from the manual ...
... and here is a photo of a replacement pilot assembly (the exact correct part #) ...
Why does this thing have a thermopile AND a thermocouple ? I thought they did the same thing: detect a lit pilot flame and allow a valve to continue providing gas to the pilot. The "thermopile" seems to connect with two wires, as I expect, as it provides a signal of some millivolts to enable gas flow. The "thermocouple" seems to connect with a small gas line of some kind. What's the deal here ?

