Originally Posted by BigBob1H
Yes, this pressure switch has three wires.
Always dislike that set up.
Check your vent system. Probably not closing the pressure switch all the time.
Once in a while they also get moisture in the hoses to the switch.
Should use a manometer to see what pressure the switch is sensing.
Did you talk to the York company. Or an Independent York distributor, or a York dealer.
York tech reps WON"T take to a home owner. And WON"T give diagnostics without getting diagnostic info from you, that you didn't provide in your post.