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View Full Version : Goodman GMT090-4 won't ignite


donaspen
Jan 16, 2012, 09:20 AM
Trying to fix a 10yo GMT090-4 gas furnace here. It's been failing to ignite intermittently for a couple of months, but a power cycle or three "fixed" it until last week. Now it seldom ignites, and when it does it won't stay on for very long. Good thing we are having a really mild winter here.

ID blower sounds kind of tired but still activates the pressure switch every time. Water heater works as usual so I'm assuming gas supply is OK.

What I'm finding though when taking ACV on the gas valve is that it's showing nothing when the valve is ON. But when I turn the valve OFF I get a 24V reading on it every time after the blower and HSI come on. Turn the valve back on and the reading goes back to zero...

This is not normal is it? Would this seem like a bad gas valve?

donaspen
Jan 16, 2012, 09:21 AM
Forgot to mention the unit is blinking once indicating ignition failure.