SiBE01-829 Troubleshooting
Service Diagnosis 45
4.3 Freeze-up Protection Control, High Pressure Control or
Indoor Heat Exchanger Thermistor Abnormality
Remote
Controller
Display
A5
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.)
Freeze-up protection control (operation halt) is activated during cooling operation according
to the temperature detected by the indoor unit heat exchanger thermistor.
The temperature detected by the indoor heat exchanger thermistor is used to determine
thermistor error.
Malfunction
Decision
Conditions
High pressure control
During heating operations, the temperature detected by the indoor heat exchanger
thermistor is above 68°C.
Freeze-up protection
When the indoor unit heat exchanger temperature is below 1°C during cooling operation.
Indoor Heat Exchanger Thermistor Abnormality
When the input voltage of thermistor during the compressor is operating is 4.96V or more.
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.
Stop valve closed.