165
16.5.5 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.
Is the 3 way valve closed?
Open the 3 way valve.
Check the 3 way valves.
Check for clogged
expansion valve or strainer.
Is the expansion valve or
strainer clogged (ice formed)?
- Replace the expansion
valve and/or strainer
- Reclaim and recharge
refrigerant
Check the indoor ref. pipe
temperature sensor.
Does it conform to the
sensor characteristic chart?
Replace the indoor ref. pipe
temperature sensor.
No
Yes
No
Yes
No
Yes
Turn ON the power and measure the DC
voltage pin 1 & 3 (GND) of CN-HPS
before and after run the system.
Is the measured voltage
before and after run the
system unchanged?
- Defect in outdoor unit
PCB (main)
- Replace the outdoor
unit PCB (main)
- Defect in outdoor high
pressure sensor
- Replace the outdoor
high pressure sensor
No
Yes
Troubleshooting:
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Caution