I have a Trane XE 80 Furnace. My problem is that we woke up this morning to a cold house and the furnace blowing cold air. I first thought was that the fire sensor needed cleaning. But after cleaning and restarting the furnace I found that the flame would go out after the burner was lit and the furnace running at full pace.
Upon examination, I triggered the problem when I moved a wire attached to the pressure switch. The wires seem to have a solid connection to the switch however. The diaphragm operated switch is on the verge of open/closed once the fan turns on under a call for fire. My first though was to change this pressure switch. I found this to be an expensive proposition.
Is there a way to test the pressure from the induction draft motor chamber to determine if the problem is in the switch versus a low pressure problem within the chamber?