Gree GMV6 DC Inverter VRF Units Service Manual
2.140 "U3" Power Phase-Sequence Protection
Fault display: main board of outdoor unit, wired controller of indoor unit and receiver of indoor unit
display
Fault diagnosis:
Check the three-phase power of the unit. If the power is connected incorrectly, thereby causing
phase loss or reverse phase, the unit generates a fault.
Possible causes:
■ The power is connected wrongly or phase loss or reverse phase occurs
■ Abnormal detection circuit
Troubleshooting:
"U3" Power Phase-
Sequence Protection
The detection circuit may
operate improperly
Yes
Whether the
three-phase power supply is
connected properly?
No
Replace the main control
board
2.141 "U4" Refrigerant Loss Protection
Fault display: main board of outdoor unit, wired controller of indoor unit and receiver of indoor unit
display
Fault diagnosis:
Check the high pressure and the low pressure of the unit by the pressure sensor. If the
temperatures corresponding to the high pressure and the low pressure of the unit are below the ambient
temperature for over 5, the unit will not start operation for safety purpose.
Possible causes:
■ Insufficient refrigerant in the unit;
■ The pipes leak.
Troubleshooting:
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