Malfunctions - Daikin 3MKS50E3V1B Service Manual

Control Specification

4.13 Malfunctions

4.13.1 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. 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 315 for detail.
4.13.2 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.
Detail
4.13.3 Refrigerant Shortage Control
Outline
I : 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.
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 296 for detail.
122
If the inverter current exceeds 14 ~ 20 A (depending on the model), the system shuts down
the compressor.
If the OL (compressor head) temperature exceeds 120 ~ 130°C, the compressor stops.
Refrigerant shortage zone
40 ~ 55 Hz
Frequency
(depending on
the model)
(R11685)
Target discharge
pipe temperature
Refrigerant shortage
zone
(R1391)
SiBE121135
Function and Control