I changed the thermocoupler but problem remains the same: pilot goes out after about 10-15 minutes. I have Williams model 250912. Please help! How do I test if new thermocoupler is also bad, beside replacing with another new thermocoupler? thanks
Heating & Cooling - Williams - 2509612 Ceramic Mid-Size Heater
Answers & Comments
Remove the thermocouple and take a pencil eraser to the hole. Clean the corrosion out the hole. Reconnect the thermocouple tight. The tip of the flame must hit the tip of the new thermocouple.
If the flame is hitting the middle of the thermocouple that is called wash through (no good) The bimetal tip of the thermocouple is made of nickel and copper layered. When heated it produces millivolts. This holds the electromagnet in and that is your safety feature. Thank you Ralph Nader.
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If the problem you have persists and you have done the suggested stuff then you are going to have to change that whole gas valve out. One other thing is take an old tooth brush and clean the pilot. Sometimes crud gets on the orifice and clogs it a hair and the flame ain't as good as it ought to be.