Gree U-Match 6 Series

GREE U-Match 6 SERIES UNIT SERVICE MANUAL
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3.4.4 “E3” Compressor Low-pressure Protection, Refrigerant Lacking
Protection, Refrigerant Recovery Mode
Error display:
ODU mainboard, IDU wired controller and IDU receiver light board will display E3
Compressor Low-pressure ProtectionError judgment condition and method:
It is judged through the action of low pressure switch. If the low pressure switch is cut off, it is judged
that low pressure is too low and the system stops operation for protection.
“E3”Possible reason:
■Cut-off valve of ODU is not fully opened;
■Low pressure sensor is abnormal;
■Outdoor or indoor fan is not working properly;
■IDU filter or air duct is blocked (cooling mode);
■Ambient temperature is too low;
■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