Carrier 58STA/58STX No Heat

nam11b

Tried to use the furnace for the first time this season and our furnace will not start (North Texas and damn good insulation). I am leaning towards the control board, but I will detail my troubleshooting and would appreciate any additional advice. The thermostat calls for heat, but I get a 31 error code. My inducer motor will not come on.

I confirmed 120VAC and 24VAC to the board and when I initiate self test, the blower motor comes on, but the inducer motor does not. I have a good common ground across the unit.

I checked all limit and roll out switches and I have 0 ohms across all switches. I am able to actuate the pressure switch and observe resistance drop to 0.

I do not have 120VAC to the inducer motor and wiring between the motor and is good. I shorted R and W on the board and still do not see 120 at the board or at the motor.

Anybody have any other ideas? The control board is a HK42FZ013. Thanks

Marty S.

Looks like you have it figured out. The replacement board isn't a plug and play so read the directions.

yuri

Yep. Follow the wiring instructions VERY CAREFULLY as it is a retrofit board with adaptor cables. Be VERY carefull how you install the large 20 pin flat connector.

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nam11b

Alright, going to order the board, I will update later this week. Hopefully I didnt miss something small!

yuri

Nope, they had problems with solder joints breaking and the ventor fan relay could be faulty also. The new board is better.

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nam11b

Well, got back from a business trip today and the new board was waiting for me. Took me about 10 minutes and got it installed and had heat back. Thanks for the advice!