SiBE12-908
Control Specification
Function and Control
52
3.13 Malfunctions
3.13.1 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. Fin thermistor
4. Gas pipe thermistor
5. Outdoor air thermistor
6. Liquid pipe thermistor
Relating to CT Malfunction
When the output frequency is more than 52 Hz and the input current is less than 1.25A, carry
out abnormal adjustment.
3.13.2 Detection of Overload and Overcurrent
Outline
In order to protect the inverter, detect an excessive output current, and for protecting
compressor, monitor the OL operation.
Detail
If the OL (compressor head) temperature exceeds 120~130°C (depending on the
model), the compressor gets interrupted.
If the inverter current exceeds 22 A, the system shuts down the compressor.
3.13.3 Refrigerant Shortage Control
Outline
If a power consumption is below the specified value in which the frequency is higher than the
specified frequency, it must be regarded as refrigerant shortage.
In addition to such conventional function, if the discharge pipe temperature is higher than the
target discharge pipe temperature, and the electronic expansion valve is fully open more than
the specified time, it is considered as an refrigerant shortage.
With the conventional function, a power consumption is weak comparing with that in the normal
operation when refrigerant is insufficient, and refrigerant shortage is detected by checking a
power consumption.
When operating with refrigerant shortage, although the rise of discharge pipe temperature is
great and the electronic expansion valve is open, it is presumed as refrigerant shortage if the
discharge pipe temperature is higher than the target discharge pipe temperature.
Refer to “Refrigerant Shortage” on page 154 for detail.
(R7164)
Refrigerant shortage zone
Frequency
40 class: 51 Hz
50 class: 48 Hz
P
ow
e
r c
o
n
sum
pt
io
n
(R1391)
Refrigerant shortage
zone
