Samsung AVMKH020EA0 Service Manual page 187

8
Troubleshooting
8-2-4. Low pressure switch detection
Outdoor unit display
Indoor unit display
Judgment method
Causes
✳ The minimum applicable temperature of DVM is -5°C and the system may not operate normally below the temperature by the low pressure switch.
Error reset (KEY 3)
Is both service valves open?
Yes
Test operation (KEY4)
Are all indoor units
operated normally?
Yes
Is high pressure and low
pressure normal?
Yes
Complete the test operation mode
and check for 1 unit operation
Are all the above check
items normal?
Yes
The system check is
completed.
(Operation) (Timer)
- Operation stop when low pressure is lower than 1.2kg/cm
- System down if the two times of the same situation occurs after restarting
- (Counter cleared if no defection for 1 hour)
- Low temperature start(outdoor temperature is lower than -5°C
- Leakage / Shortage of refrigerant
- Compressor unloading failure
- Service valve clogged/electronic expansion valve clogged
No
No
No
No
- 186 -
(Fan) (Filter) (Removing frost)
G(sensor open)
2
Since the service valve is clogged, open
the service valve.
Since it is the electronic expansion valve
close error, check the electronic expansion
valve and PCB related.
Since the refrigerant is insufficient,
check to charge if needed.
Operating
pressure
(kg/cm 2 G) 1.2±0.2
Low switch specification
No
Is the low pressure
rapidly dropping and the
discharge temperature
increasing?
Yes
Since it is the defect of compressor
unloading, check the coil end of PWM
valve. If there is no trouble in the coil,
replace the PWM valve.
OPEN CLOSE
2.2±0.2