York Diamond 90 - 3 flashes and a humming inducer motor
I returned from the Thanksgiving weekend to find my house cold and the heat not working. Fortunately it's not terribly cold yet here in the Mid-Atlantic.
I will preface by saying that I know NOTHING about furnaces, but have educated myself by reading the manual as well as this and other internet forums. Thanks to all the participants.
Here's where I'm at: I have a York Diamond 90 furnace that is flashing 3 red blinks when turned on. This is the infamous pressure switch failure that seems to often indicate an issue with the inducer.
When I turn on the heat, after about 2 seconds a fairly loud humming comes from the inducer assembly. It gradually begins to warm up if I leave it on, but I can't tell if there is any other mechanical action from within and am unsure how to proceed with further diagnostics.
Is the humming an indication of an inducer failure? Am I better off calling a professional at this point? Or is there an easy way to get inside and see what else might be the issue?
As with all 90's . make sure condensate is draining from the 2 nd heat exchanger. It could be stopped up causing water to back up into /or picked up by the exhaust fan. This water is very aicdic & if it gets into the fan . it will rust away the fan/ squirrel cage & cause the ps not to function correctly