Have HVAC Questions? Ask an HVAC Expert for Answers
There is an additional charge for a phone call and I first need more info about your situation. If you still feel the need to talk you can request a call later but first I need the actual model number of your unit (it's on the rating tag inside the burner compartment).
You're already there. I need your model number so I can help with your issue
How old is this unit? It's be around for almost 20 years with a number of variations along the way. If you don;t know give me the serial number I can probably figure its age from that
What sequence is the LED on the control board (in the blower compartment)? Do you have spark ignition or HSI (hot surface ignition, a "glow plug")?
Nothing is flashing? No flash indicates normal operation. If the thermostat is calling for heat, turn the power off to the furnace wait a minute then turn it back on. Tell me what happens
If the igniter is arcing you need to check for 24 volts at the gas valve. Do you have a multi-meter?
I don't understand your last post
You need to test for 24 volts AC across the 2 leads on the gas valve while the igniter is arcing. If you have nothing there trace the leads back to the board and test there. You'll have to rig the blower door/panel switch closed so you have power to the unit if you have to test at the board
Then the gas valve should open and the burners should ignite. This is an indication of a problem with the gas valve
If gas supply pressure is adequate and the burners are clean then you probably need a new gas valve. We would test manifold pressure to rule the above in or out
Ok, the above still applies. I'd be more concerned about no voltage due to a testing error than a positive voltage reading.
I can't confirm your testing technique from here. All I can tell you is what needs to be tested. If you have 24 volts at the valve then it should open and the burners should fire up. If you don't have 24 volts then you could have a bad connection between the board and the valve or a bad board.
What's the flash sequence? how many times does it flash before it repeats?
That's not indicating an error
Normal operation after an ignition failure is to try to 4 times then lock out for an hour and flash once followed by a 2 second pause
Green is the ground. You need to probe yellow and blue.
If you have voltage to the valve that's the only thing that's relevant. If there was a problem with the other devices you wouldn't have voltage to the valve.
I'd appreciate a favorable rating