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17.5.5 Service Valve Error (H27)
Malfunction Decision Conditions:
During cooling operation, when:-
[a] Indoor refrigerant pipe temperature at compressor startup - present indoor refrigerant pipe temperature < 2°C
[b] Present high pressure - high pressure at compressor startup < 5kg/cm
2
**Judgment only for first time cooling operation and not during pump down operation.
Malfunction Caused:
1 3 way valves closed.
2 Faulty high pressure sensor.
3 Faulty indoor refrigerant pipe temperature sensor
4 Faulty outdoor unit PCB (main).
Abnormality Judgment:
Continue for 5 minutes.
Troubleshooting:
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Open the 3 way valve.
Replace the indoor ref. pipe
temperature sensor.
- Defect in outdoor unit
PCB (main)
- Replace the outdoor
unit PCB (main)
- Defect in outdoor high
pressure sensor
- Replace the outdoor
high pressure sensor
Check the 3 way valves.
Is the 3 way valve closed?
Check for clogged
expansion valve or strainer.
Is the expansion valve or
strainer clogged (ice formed)?
Check the indoor ref. pipe
temperature sensor.
Does it conform to the
sensor characteristic chart?
Is the measured voltage
before and after run the
system unchanged?
Turn ON the power and measure the DC
voltage pin 1 & 3 (GND) of CN-HPS before
and after run the system.
No
No
No
No
Yes
Yes
Yes
Yes
- Replace the expansion
valve and/or strainer
- Reclaim and recharge
refrigerant
Caution
