Control Specification
SiBE041134EB
50
Functions and Control
3.12 Malfunctions
3.12.1 Sensor Malfunction Detection
Sensor malfunction can be detected in the following thermistors:
1. Outdoor heat exchanger thermistor
2. Discharge pipe thermistor
3. Radiation fin thermistor
4. Outdoor temperature thermistor
3.12.2 Detection of Overcurrent and Overload
Outline
An excessive output current is detected and the OL temperature is observed to protect the
compressor.
Detail
If the OL (compressor head) temperature exceeds 120 °C, the system shuts down the
compressor.
If the inverter current exceeds 9.25 A, the system shuts down the compressor.
3.12.3 Refrigerant Shortage Detection
Detecting by discharge pipe temperature
If the discharge pipe temperature is higher than the target discharge pipe temperature, and the
electronic expansion valve is fully open for more than the specified time, it is regarded as
refrigerant shortage.
Detecting by the difference of temperature
If the difference between suction and discharge temperature is smaller than the specified value,
it is regarded as refrigerant shortage.
Refer to page 66 for details.
(R1391)
Target discharge
pipe temperature
Refrigerant shortage
zone
