Control Specification SiBE121135_A
127 Function and Control
4.13.3 Refrigerant Shortage Control
Outline I : Detecting by power consumption
If the input current is below the specified value and the frequency is higher than the specified
frequency, it is regarded as refrigerant shortage.
The input current is low comparing with that in the normal operation when refrigerant is
insufficient, and refrigerant shortage is detected by checking input current.
II : Detecting by discharge pipe temperature
If the discharge pipe temperature is higher than the target discharge pipe temperature, and the
outdoor electronic expansion valve is fully open for more than the specified time, it is regarded
as refrigerant shortage.
Refer to “Refrigerant shortage” on page 200 for detail.
4.13.4 Anti-icing Function
During cooling, if the indoor heat exchanger temperature in the operation stopped room
becomes below the specified temperature for the specified time, the outdoor electronic
expansion valve is opened in the operation stopped room as specified, and the fully closed
operation is carried out. After this, if freezing abnormality occurs more than specified time, the
system shuts down as the system abnormality.
Frequency
Input current
Refrigerant shortage zone
(R18382)
40 ~ 55 Hz
(depending on
the model)
(R1391)
Refrigerant shortage
zone
Target discharge
pipe temperature