My Bryant furnace is giving me fits. It stopped working yesterday, meaning the inducer motor was running, but the burners were not igniting. I turned off the thermostat, cleaned out some dust and looked for loose wires, turned the thermostat back on, and she lit up and ran. Then last night, the same issue returned, where the inducer motor ran but no ignition. I tried the thermostat trick several times, but nothing. Finally, after an hour or so, I gave up and shut off the thermostat.
I did notice the flashing red LED below, and consulted the manual to find the flashing leads to a code. One long flash, three short means a fault code "31". This equates to "Pressure Switch Not Closed", and directs me to check the PVC pipes leading to the combustion chamber, and check the air intake pipes outside the house. All clear from what I see. An hour later, I turned the thermostat back on, and the darn thing lit up and ran. Well, this morning, no heat. Now I'm befuddled. I try the thermostat trick, with no result. Same flashing, fault code 31. I take off the the cover to the burner assembly, clean out some minor debris, pull out the igniter, re-install it, reseat the connections, put it all back together, and she fires up. What the hell do I have here? Is there a connection that could be the cuplrit? Is it a circuit board or bad switch? What/where is the "Pressure Switch"? Anybody have any insight? Thanks!