Carrier Circuit Board Kit 325878-751


Carrier circuit board kit P/N 325878-751

This main control board kit replaces part numbers: HK42FZ004, HK42FZ007, HK42FZ008, HK42FZ009, HK42FZ011, HK42FZ013, HK42FZ016

Using the genuine Carrier part instead of a cheaper aftermarket part is the best choice for this board. We listed the response we received from Carrier Corp about using aftermarkets boards below the link to the video. The biggest issue I pick out of the response aside from the reliability issues is the blower fan is not programmed to cool the heat exchanger properly and will cause stress cracks in the heat exchanger. The efficiency of the furnace will also be less

The main board in this kit is P/N HK42FZ034. If you are replacing a circuit board with one of the above part numbers you will need this kit. It contains necessary wiring harness for changes along with instructions

Some models this board is used in begin with: 340MAV, 345MAV, 350MAV, 351DA, 373LAV, 376CAV, 383KAV, 393AAV, 395CAV, 480BAV, 481BAV, 490AAV, 58MCA, 58MSA, 58MXA, 58PAV, 58RAV, 58WAV, 58YAV, 58ZAV, GB1AAV, GB3AAV, PG8DAA, PG8UAA, PG9MAA

Genuine Carrier parts

Shipping rate for continental United States

Click this link for a short video with information about this part

There is a replacement board on the market for this board that is made by ICM. I have been asked repeatedly why the Carrier replacement is more expensive. The following is cut and pasted from an email from Carrier Corp and explains the difference in the 2 boards

Thanks for the note.  I must inform you that our Engineering community has reviewed the specs on ICM boards, and have determined the following issues:

This control has 60 second on-delay only. If used on an 80% product it will have major HX (heat exchanger failure issues.

Since they do not detect furnace type or backward compatibility they will probably have one post purge timing. They may not have pre-purge or post purge at all. 

The cool relay is rated for 10 amps only and ours is rated for 20 amps.

We have an unpublished internal safety algorithm that this control does not have. It relates to flame sense.

If running continuous fan or heat pump mode they may not shut the blower  off when the igniter is energized. If not this could cause nuisance circuit breaker trips.

The control has higher resistance load resistors and may have compatibilty problems with some thermostats. (Based on photo)

The control may not shut off the HSI the moment that flame is sensed. This will give reduced reliability on a Power Heat igniter.

When replacing one control in twinned furnaces both controls must be changed.

Carrier's flame sense software is quite extensive in regards to checking the circuitry and how it detects flame. This control may not supply the same level of safety as theiir software.

These controls may not be UL or CSA listed 


  • Model: 325878751
  • Manufactured by: Carrier