GREE U-Match 5 SERIES UNIT SERVICE MANUAL
44
■Refrigerant charging amount is insufficient;
■System pipeline is blocked;
Troubleshooting：
E3 protection
Check if the
system low
pressure is lower
than 0.05MPa
No
Yes
Charge
refrigerant
according to the
requirement and
then turn on the unit
to see if E3
protection still
occurs
Yes
Enter
debugging mode
through wired
controller and select
without refrigerant
lacking protection; then
turn on the unit to see
if E3 protection still
occurs
No
Completely open the liquid
valve and gas valve of outdoor
unit
Check if the liquid
valve and gas
valve of outdoor
unit open
completely
Yes
Yes
Yes
Weld the leakage point and
recharge refrigerant after
vacuum pumping and pressure
retaining are passed
Check if there is
leakage in the
pipeline
Reconnect wire according to
the circuit diagram or replace
the pressure switch
Yes
35-85 outdoor units
are without low pressure switch and
check if the wiring of mainboard is
normal;100-160 outdoor units are
with low pressure switch and
check if the low pressure
switch and its wiring
are normal
Replace the outdoor main
control board
No
3.4.4 ―E4‖ Compressor Air Discharge High-temperature Protection
Error display: ODU mainboard, IDU wired control and IDU receiver light board will display E4
Error judgment condition and method:
Test the compressor discharge temperature through compressor discharge pipe and shell top temperature sensor. If the tested
temperature value is higher than 115℃, the unit will stop for protection
Possible reason：
■Cut-off valve of ODU is not fully opened;
■Electronic expansion valve is abnormal;
■Outdoor or indoor fan is not working properly;
■IDU filter or air duct is blocked (cooling mode);
■Ambient temperature exceeds allowable operation range;
■Refrigerant charging amount is insufficient;
■System pipeline is blocked;
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