Carrier 58rav not heating

Hello, I have a 10 year old Carrier furnace and it suddenly stopped working. I get LED code 31. I see no damaged wiring inside unit. When I set the thermostat to heat and increase the desired temperature, the thermostat relay clicks but nothing happens inside the furnace. The inducer motor does not turn on and I have measured for power at the motor terminals and nothing. Several seconds later the LED goes from solid red to code 31.
Any ideas? Thanks !
bob

 

What does the error code key say about a 31 code? If the vent fan does not start & you are not getting power to the fan motor, check for power at the venter terminals on the board. If no power there, I suspect a bad board.

 

Code 31 = pressure switch not closing. (pressure switch normally closes to prove proper draft when inducer comes on)

Check for power at the inducer motor connections on the board (depress blower door safety switch so unit powers up) before replacing any parts.

 

Fuse on the circuit board? There should be a panel on the inside or on a surface somewhere telling you what the code means

 

Replace the circuit board. The circuit board is failing to energize the inducer motor.



If you want to jury rig power to the inducer motor to cause it to run continuously, you can probably get heat until you replace the circuit board.

 

Correct me if I'm wrong, but I think many circuit boards check for (stuck) closed pressure switches when there isn't a call for heat as a safety feature.

 

Muggle, you are correct, but the contol would throw a code for a closed pressure switch.

 

My Carrier 58rav Draft Inducer Motor wouldn't run which resulted in no heat cycle. This motor forces burnt gases out the flue vent and must run before and during the heat cycle. No 115 volts at terminals of inducer motor. Everything else checked ok. I rigged a spare electrical cord and ran AC from an outlet to the motor terminals to see if the motor worked. It did, and the furnace completed a heat cycle which meant the control panel was not putting 115 v to the motor. I wouldn't leave a rigged cord on motor, only to test.

The control panel was bad. I had a part number HK42FZ004 which has been replaced by 325878-751. Amazon has them for $165 plus shipping.

Open the control panel by prying apart the black plastic case at the edges. Some people have repaired the control panel by re-soldering resistor R33. Mine looked like a cold solder but it was ok. My capacitor C15 was bad. C15 is part of the Inducer motor relay circuit. I replaced C15 (47 microfarad, 63 vdc) for $1 and the board now works fine. Furnace runs great.

 

Ignition controls are not designed to be repaired and manufacturers recommend against repairing them, and for good reason.

Be smart and buy a new circuit board.