Burned White-Rodgers 50A50-471 Furnace Control Board
I woke up this morning full of Christmas cheer and then I noticed it was too cold (I have compromised with my wife to turn the heat down to 65 degrees at night, but not 60! Brrr!)
I noticed the circuit breaker was tripped so I reset that. The circulation blower comes on but no ignition or heat. The White Rodgers 50A50-471 control board was blinking 3 times meaning "problems with pressure switch".
Now it gets interesting... I overrode the pressure switch and thereby fooled the control board (it started blinking in "call for heat" sequence). After a 30 second delay or so I got ignition (then I realized it is not a good idea to override safety switches, when I singed a few hairs on my hand). But the draft induction motor did not come on no matter what I did, which is why the pressure switch would not close.
I opened up the White Rodgers control board and found a big burned spot right by the plug to the induction motor. But remember, I said that the board seemed to be working fine except that the induction motor would not turn on. I have included pictures.
[IMG] Motor+Board+#2.JPG (image) [/IMG]
[IMG] Motor+Board+#1.JPG (image) [/IMG]
My dilemma is this: what caused the burnout and circuit breaker trip, the motor or the control board? If I replace the board (~$100) which otherwise seems to be working and then find that the motor is bad, I will just burn up another board. If I replace the motor (~$200) and it still doesn't work, then I know the board is bad and I just bought an unneeded motor.
Any ideas?