Gree GMV-VQ680WM/C-X Service Manual page 219

Gree
2.177 Ineffective Cooling and Heating
Applicable models: all indoor units
Fault diagnosis:
1) In cooling mode, when the electronic expansion valve is open to 2000PLS or 480PLS, the
temperature of outlet pipes of the indoor unit coil is over 5°C greater than the temperature of
inlet pipes of the indoor unit coil;
2) In heating mode, when the electronic expansion valve is open to 2PLS, the temperature of inlet
pipes of the indoor unit coil is over 12°C less than the saturation temperature corresponding to
the high pressure;
Possible causes:
■ The check valve of the outdoor unit is not opened fully as required.
■ The unit pipes are clogged.
GMV6 HR DC Inverter VRF Units Service Manual
"y8" indoor air box
sensor general error
Check if the monitor software
displays air box and the test data
No
Check if the communication cord
between main control board and air box
loose or any foreign objects inside? If it is
loosened or there are foreign objects,
retighten it after treatment
Is the error disappeared?
No
Replace the corresponding air box or
monitor software which can't be
detected, or the air box which the
monitor software displays abnormal
test data
Is the error disappeared?
No
Replace the main board
217
Yes