Gree GMV-VQ680WM/C-X Service Manual page 139

Gree
After confirming that the EXV coil is connected properly, power off the unit. Then power on to reset
the unit and check the resetting action. If unable to reset the unit, replace the coil or the main board. If
able to reset the unit normally, inspect other parts of the unit.
Step 4: Check whether the refrigerant is added in accordance with the design requirements, as
excessive refrigerant may trigger system protection.
Solution: Add refrigerant in accordance with the design requirements.
2.73 "E3" System Low Pressure Protection
Fault display: main board of outdoor unit, wired controller of indoor unit and receiver of indoor unit
display
Fault diagnosis:
The low pressure sensor detects the compressor's suction pressure. When the saturation
temperature corresponding to the low pressure is below -41°C, the unit stops to ensure safe operation.
Possible causes:
■ Check valve of the outdoor unit is closed;
■ Abnormal low pressure sensor;
■ Abnormal outdoor or indoor fans;
■ Clogging of indoor filter or air duct (cooling mode);
■ The ambient temperature where the unit operates is too low;
■ Insufficient refrigerant in the unit;
■ Clogging of unit pipes.
Troubleshooting:
GMV6 HR DC Inverter VRF Units Service Manual
137