Haier GE Connect Series Service Manual page 49

Maintenance
Labels on the 4-way valve:
D-connect to the discharge side; E-connect to the
evaporator of indoor unit; S-connect to the suction side of
the liquid separator; C-connect to the outdoor coil.
When the system is in cooling mode, C-the pipeline is with
high pressure and high temperature; E, S-the pipeline is
with low pressure and low temperature.
When the system is in heating mode, E-the pipeline is with
high pressure and high temperature; C, S-the pipeline is
with low pressure and low temperature;
Because D is connected to the discharge side, it is with high
pressure and high temperature regardless of the operating
mode. When the unit is powered on, in defrosting or oil
return mode, the 4-way valve will produce some noise. Do
not touch the pipes directly with your hands and be aware
of the hot temperature.
4. Check the drive board of compressor, i.e. the IPM module. Please refer to the IPM checking method in the
section of troubleshooting. Check the drive board of compressor, i.e. the IPM module. Please refer to the
IPM checking method in the section of troubleshooting.
Diagnosis of Compressor Failure: On Condition that the Unit CANNOT be Started Up
1. Cut off the power supply and detach the cover of the wiring box of the compressor. Check the wiring
connections of the compressor.
2. Check the resistance between the wiring terminals (U, V, W) of compressor.
Refer to the following table for the resistance between any two terminals:
Compressor model
QXFT-F310zN450
QXAU-F516zX440A
Measure the resistance to ground of each wiring terminal. The resistance should be above 10 megohm. If not,
we can judge that the compressor windings are grounded.
3. On condition that the unit cannot be started up; we also need to check the solenoid valve assembly of the
system including the electronic expansion valve. The checking method is the same as instructed above.
4. Check whether the IPM module is normal. Please refer to the IPM checking method in the section of
troubleshooting.
Use a multimeter to measure the resistance
between two terminals
Measure the resistance to ground
of the three terminals respectively
UV Winding Resistance
0.79±7%Ω
CONNECT SERIES SERVICE MANUAL
D- Connect to the exhaust side
Caution! High temperature!
VW Winding Resistance
0.79±7%Ω
WU Winding Resistance
0.79±7%Ω
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