Mitsubishi Air Source Heat Pump Error Codes

0403 Serial communication error/Panel communication error
0404 Indoor unit EEPROM abnormality
1102 Discharge temperature fault
1301 Low pressure fault
1302 High pressure fault
1500 Refrigerant overcharge
2500 Drain sensor submergence
2502 Drain pump fault
2503 Drain sensor (Thd) fault
2600 Water leakage
2601 Water supply cutoff
4102 Open phase
4106 Transmission power supply fault
4109 Fan operation status detection error
4115 Power supply signal sync error
4116 RPM error/Motor error
4121 Function setting error
4124 Electric system not operate due to damper abnormality
4230 Heatsink overheat protection
4240 Overload protection
4260 Heatsink overheat protection at startup
5201 High-pressure sensor fault (63HS1)
5401 Humidity sensor fault
5701 Loose float switch connector
6201 Remote controller board fault (nonvolatile memory error)
6202 Remote controller board fault (clock IC error)
6600 Address overlap
6601 Polarity setting error
6602 Transmission processor hardware error
6603 Transmission line bus busy error
6606 Communication error between device and transmission processors
6607 No ACK error
6608 No response error
6831 MA controller signal reception error (No signal reception)
6832 MA remote controller signal transmission error (Synchronization error)
6833 MA remote controller signal transmission error (Hardware error)
6834 MA controller signal reception error (Start bit detection error)
6840 A control communication reception error
6841 A control communication synchronism not recover
6842 A control communication transmission/reception hardware trouble
6843 A control communication start bit detection error
6846 Start-up time over
7100 Total capacity error
7101 Capacity code setting error
7102 Wrong number of connected units
7105 Address setting error
7106 Attribute setting error
7110 Connection information signal transmission/reception error
7111 Remote controller sensor fault
7113 Function setting error (improper connection of CNTYP)
7117 Model setting error
7130 Incompatible unit combination


The last digit in the check error codes in the 4000’s and 5000’s and two-digit detail codes indicate if the codes apply to compressor inverter on fan inverter.
Code 4225 (detail code 108): Bus voltage drop in the fan inverter system
Code 4230 : Heatsink overheat protection in the compressor inverter system

The last digit= 0 or 1 = Compressor inverter system

The last digit= 5 or 6 = Fan inverter system

Service Book PDF

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