45 MBCA Ductless Unit and the “CP” Error Code
June 12, 2025
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Most ductless products have all of the error codes listed in the installation and service manuals. Error codes listed in
Technical Services Manager
North Alabama District
The HVH8 compressor operates with 3-phase variable frequency Pulse Width Modulation (PWM). To troubleshoot a fault related to the code use the following steps.
1. Disconnect compressor power leads from the inverter (MOC Board) terminals, U (Yellow), V (Red), and W (Black).
2. Measure the resistance between yellow to red, yellow to black, and red to black. Then check the values with table 7 in the installation
book. Each value should be equal.
3. Measure the resistance to ground for each lead.
4. If the resistance checks out, reconnect power leads to appropriate terminals.
5. If the resistance appears to be abnormal, it will be necessary to measure the resistance at the compressors fusite terminals.
6. During the removal of the compressor fusite cap, do not remove the RTV sealant. Remove the harness plug, measure resistances, and compare to table 7.
7. Special care will need to be taken with the replacement of the compressor fusite cap. Make sure the two holes in the compressor fusite terminal box are still full of RTV sealant before the cap is reinstalled. The factory RTV can be reused as long as none of it has been removed during the cap removal.
8. Reinstall compressor sound blanket making sure the discharge thermistor and compressor power harness are routed as they were from the factory.
Most ductless products have all of the error codes listed in the installation and service manuals. Error codes listed in
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