09-20-2007, 10:22 PM
Turn up the T stat on my fau and I get forced cold air--no heat. The electric glow plug works just fine, but of course after a minute, shuts itself off because there is no gas. I figure it is a broken gas valve or a broken solid state electronic box. How do you test a gas valve? It has two terminals. I have put 24 volts plus and minus to each terminal, I get small sparks, but no gas flow to the burners. Should I disconnect the hi temperature shut off for the test? The gas valve has an electromagnet in it that opens the gas valve when energized. Buit how do you test it? Of course I have lots of gas in the supply pipe.