Malfunctions - Daikin 4MXL-T Series Service Manual

SiUS121827E

4.14 Malfunctions

4.14.1 Sensor Malfunction Detection
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
4.14.2 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 27.5 ~ 29 A (depending on the model), the system shuts down
 If the OL (on the side of the compressor body) temperature exceeds 125°C (257°F), the
4.14.3 Refrigerant Shortage Control
Outline
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.
Reference
Refer to Refrigerant shortage on page 195 for details.
4.14.4 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 operation stopped room as specified, and the fully closed operation is carried out. After this, if
freezing abnormality occurs longer than specified time, the system shuts down as the system
abnormality.
Part 4 Functions and Control
the compressor.
compressor stops.
Refrigerant shortage zone
40 Hz
Frequency
Control Specification
R4003425
121