Brett Stewart

VRF Tech Support & Equipment Verification Southwest District

June 12, 2025

45 MBCA Ductless Unit and the “CP” Error Code

Most ductless products have all of the error codes listed in the installation and service manuals. Error codes listed in the manual for a unit will give either a brief description of the code or sometimes a more in-depth meaning of the code with some potential resolutions. Knowing how to understand your error codes and come up with a resolution will help save time and get your unit back up and running.

Wall-mounted digital thermostat on a wall, glowing blue and showing “CP” and 13:05.
Close-up of an air conditioner control panel showing “CP” on a black circular display.

The “CP” error code is a hard error code to find in the installation and service manuals. Many of your manuals don’t even list the “CP” error code. I personally could not find the “CP” error code in the manuals for the 45 MBCA unit I was working on, it was from previous experience by others to help resolve the “CP” error code.

45MBCA Performance™ cassette indoor unit product image on white background
White digital thermostat labeled “KSACN1401AAA” on a light background.

The “CP” error code is related to the Remote ON-OFF on the indoor circuit board of the unit. The remote ON-OFF contacts are typically labeled CN23 on the board, which is a three terminal plug. As long as the contacts are closed between terminals one and three the unit will run. If the contacts become open between one and three the unit will no longer run. A controls company will sometimes utilize this set “on” contacts on the board to turn the unit ON and OFF.


Disclaimer: The technical statements, information and recommendations contained herein are believed to be accurate as of the date hereof, but Mingledorff’s does not make representations or warranties, express or implied, as to its accuracy, its completeness, or the results to be obtained. The information is being provided for informational purposes only and is intended for use by persons having adequate skill and expertise regarding the proper selection, use and application of the products and recommendations and at their own risk and discretion.


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