Mitsubishi Electric PUHY-HP144TSHMU-A Service Handbook page 147

[ IX Troubleshooting ]
1. Error Code
4230
Heatsink overheat protection
2. Error definition and error detection method
When the heat sink temperature (THHS) remains at or above TOH is detected.
Model TOH
HP72, HP96 90°C[194°F]
3. Cause, check method and remedy
Cause
(1) Fan board failure
(2) Outdoor unit fan failure
(3) Air passage blockage
(4) THHS failure
Refer to section - 6 - "Inverter" under part [4] "Trouble shooting principal parts" for error codes related to the
inverter.(page 196)
HWE0716A
Check method and remedy
Refer to 9 [4] - 6 - (2) [6].(page 199)
Check the outdoor unit fan operation.
If any problem is found with the fan operation, check the fan motor. ->Refer to
9 [4] - 6 - (2) [5].(page 199)
Check that the heat sink cooling air passage is not blocked
Check the THHS sensor reading on the LED monitor.
->If an abnormal value appears, check the sensor resistance, and replace the
sensor as necessary.
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