Si04-115
Trouble shooting
Service Diagnosis
67
5.2
Operation Shutdown Due to High-Pressure Control or
Freeze-Up Protection (Thermistor Activation)
Remote
Controller
Display
A5
A5
A5
A5
Indoor unit LED
Display
Method of
Malfunction
Detection
"
High pressure control
During heating operations, the temperature detected by the indoor heat exchanger
thermistor is used for the high pressure control (stop, outdoor fan stop, etc.)
"
The freeze protection control (operation halt) is activated during cooling operation according
to the temperature detected by the indoor unit heat exchanger thermistor.
Malfunction
Decision
Conditions
"
High pressure control
During heating operations, the temperature detected by the indoor heat exchanger
thermistor is above 67°C
"
Freeze protection
When the indoor unit heat exchanger temperature is below 0°C during cooling operation.
Supposed
Causes
"
Operation halt due to clogged air filter of the indoor unit.
"
Operation halt due to dust accumulation on the indoor unit heat exchanger.
"
Operation halt due to short-circuit.
"
Detection error due to faulty indoor unit heat exchanger thermistor.
"
Detection error due to faulty indoor unit PCB.
Troubleshooting
Check No.5
Refer to P.88
NO
NO
NO
Check No. 5
Indoor unit heat exchanger
thermistor check
Check the intake air filter.
Check the air passage.
YES
YES
Check the dust accumulation on
the indoor unit heat exchanger.
YES
YES
Is there any short-circuit?
Is it very dirty?
Is it very dirty?
Does it conform to the
thermistor characteristic
chart?
NO
Provide sufficient air passage.
Clean the air filter.
Clean the heat exchanger.
Replace the indoor unit PCB.
Replace the thermistor (replace
the indoor unit PCB).
(R1945)
Caution
Be sure to turn off power switch before connect or disconnect connector,
or parts damage may be occurred.
