Service Manual

Troubleshooting SiUS091133
97 Service Diagnosis
4.3 Freeze-up Protection Control or Heating Peak-cut Control
Remote
Controller
Display
A5
Method of
Malfunction
Detection
 Freeze-up protection control
During cooling operation, the freeze-up protection control (operation halt) is activated according
to the temperature detected by the indoor heat exchanger thermistor.
 Heating peak-cut control
During heating operation, the temperature detected by the indoor heat exchanger thermistor is
used for the heating peak-cut control (operation halt, outdoor fan stop, etc.)
Malfunction
Decision
Conditions
 Freeze-up protection control
During cooling operation, the indoor heat exchanger temperature is below 0°C (32°F).
 Heating peak-cut control
During heating operation, the indoor heat exchanger temperature is above 60 ~ 65°C (140 ~
149°F) (depending on the model).
Supposed
Causes
 Short-circuited air
 Clogged air filter of the indoor unit
 Dust accumulation on the indoor heat exchanger
 Defective indoor heat exchanger thermistor
 Defective indoor unit PCB