original symptom - Pilot stays lit, heater will not turn on
While troubleshooting I would use a jumper to bypass the various switches looking for a bad switch.
The heater would come on eventually, but never while bypassing the same switch.
I suspected the thermopile was not getting enough voltage to turn on the gas valve.
I cleaned the pilot tube and orifice to make sure I had a good pilot flame - no change.
Took voltage readings on thermopile, expected 500-700 mV, only had 100-200.
Bought a new thermopile - better voltage readings 300-500 still heater would not come on without a random use of jumpers.
I assumed that the use of the jumper was creating a "spark" like jump in the millivolt range that would be enough to turn on the gas valve. As long as the heater turned on when I needed it I figured I could live with it for the rest of the season.
New season couldn't get that Lucky Spark - decided to spring for a new gas valve..... NOPE...
Maybe I got a bad Thermopile??? Bought a new thermopile ... Success!!!!!! For 3 months.....
Today the heater shut off and the pilot went out, I relit the pilot but it will not stay lit
What are the chances its another bad thermopile?
Is there something else that can be causing the thermopile to go bad?
or am I missing some other possible cause?
Any ideas are appreciated, I'm about to buy another thermopile, but I think I'm missing the real problem here.
Thanks in advance for any help