Have HVAC Questions? Ask an HVAC Expert for Answers
Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.How old is your unit? Does the igniter glow? how many times does the LED blink before it pauses and repeats?
Ok, that's odd because the specs for even the earliest version of this furnace (19 years old) show a hot surface igniter not spark ignition. You need to check for 24 vac at the gas valve while it's arcing. If you have 24 v then the gas valve is suspect. If you don't then you either have a bad board or the connection between the board and the gs valve is faulty.
You probe the 2 leads on the valve with a voltmeter
Last picture. gas valve is yellow with a brown dial on top. Probe those 2 leads connected to the gas valve while the electrode is arcing. You need to put the panel back on the blower compartment or nothing will work. The blower door switch will kill the power if it's not pushed in. Also put the cover back on the control board.
The greens are ground. My wiring diagram shows blue and yellow as the live leads
Ok, the variation could be due to a bad connection or probe contact but the voltage you read should b adequate to open the gas valve. So since you have voltage to the valve while the electrode is arcing but no gas to the burners/no ignition you probably have a faulty gas valve