Control Specification
SiSG121917E
87
Part 4 Functions and Control
Reference
Reference
4.11 Malfunctions
4.11.1 Sensor Malfunction Detection
Sensor malfunction may occur either in the thermistor or current transformer (CT) system.
Relating to thermistor malfunction
1. Outdoor heat exchanger thermistor
2. Discharge pipe thermistor
3. Radiation fin thermistor
4. Gas pipe thermistor
5. Outdoor temperature thermistor
6. Liquid pipe thermistor
Relating to CT Malfunction
Refer to CT or related abnormality on page 160 for details.
4.11.2 Detection of Overcurrent and Overload
Outline
In order to protect the inverter, an excessive output current is detected and the OL temperature
is observed to protect the compressor.
Details
If the inverter current exceeds 17 ~ 19.25 A (depending on the model), the system shuts
down the compressor.
If the OL (compressor head) temperature exceeds 130°C, the compressor stops.
4.11.3 Refrigerant Shortage Control
Outline
Detecting by power consumption
If the power consumption is below the specified value and the frequency is higher than the
specified frequency, it is regarded as refrigerant shortage.
The power consumption is low comparing with that in the normal operation when refrigerant is
insufficient, and refrigerant shortage is detected by checking power consumption.
Refer to Refrigerant shortage on page 138 for detail.
4.11.4 Anti-icing Function
During cooling, if the indoor heat exchanger temperature in the room not in operation becomes
below the specified temperature for the specified time, the electronic expansion valve is opened
in the room not in operation as specified, and is carried out with the electronic expansion value
fully closed. After this, if freezing abnormality occurs more than specified time, the system shuts
down as the system abnormality.
Frequency
Refrigerant shortage zone
(R21927)
40 ~ 54 Hz
(depending on
the model)
Power consumption
(Input current)
