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Troubleshooting
Diagnostic procedure for check code
Check code Operation cause
[A7] 1. Outdoor unit service valve closed.
Suction temperature (TS) alarm (>40°C) 2. Blockage PMV assembly on the liquid line.
3. TS pressure switch error.
4. Insufficient refrigerant, blockage in pipe.
Are the gas pipe and liquid pipe
service valves of the outdoor unit
fully open ?
Is there a blockage in the
expansion valve on the liquid line?
Open valves fully.
Replace expansion valve.
j
j
h
h
No
Ye s
Ye s
No
Insufficient refrigerant, blockage,
pipe breakage.
Are the characteristics of TS
pressure switch normal?
(N/C type)
Replace TS pressure switch.
j
h
No
Ye s
Check code Operation cause
[AA]
High pressure sensor (Pd) short circuit Pd sensor output voltage alarm
If there is an abnormal output voltage of Pd sensor: Check connector circuit (Pd sensor: PJ7) and output
voltage of the sensor.
If the sensor is normal, replace the outdoor interface PC board.
Sensor characteristics:
Input 12 V DC (± 10%) across red and black leads of the pressure sensor.
Output 0.5 to 4.5 V at 0 to 2.45 MPa across white and black leads of the pressure sensor.
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