SiBE12-908 Control SpecificationFunction and Control 523.13 Malfunctions3.13.1 Sensor Malfunction DetectionSensor malfunction may occur either in the thermistor or current transformer (CT) system.Relating to Thermistor Malfunction1. Outdoor heat exchanger thermistor2. Discharge pipe thermistor3. Fin thermistor4. Gas pipe thermistor5. Outdoor air thermistor6. Liquid pipe thermistorRelating to CT MalfunctionWhen the output frequency is more than 52 Hz and the input current is less than 1.25A, carryout abnormal adjustment.3.13.2 Detection of Overload and OvercurrentOutline In order to protect the inverter, detect an excessive output current, and for protectingcompressor, monitor the OL operation.Detail If the OL (compressor head) temperature exceeds 120~130°C (depending on themodel), the compressor gets interrupted. If the inverter current exceeds 22 A, the system shuts down the compressor.3.13.3 Refrigerant Shortage ControlOutline If a power consumption is below the specified value in which the frequency is higher than thespecified frequency, it must be regarded as refrigerant shortage.In addition to such conventional function, if the discharge pipe temperature is higher than thetarget discharge pipe temperature, and the electronic expansion valve is fully open more thanthe specified time, it is considered as an refrigerant shortage.With the conventional function, a power consumption is weak comparing with that in the normaloperation when refrigerant is insufficient, and refrigerant shortage is detected by checking apower consumption.When operating with refrigerant shortage, although the rise of discharge pipe temperature isgreat and the electronic expansion valve is open, it is presumed as refrigerant shortage if thedischarge pipe temperature is higher than the target discharge pipe temperature.Refer to “Refrigerant Shortage” on page 154 for detail.(R7164)Refrigerant shortage zoneFrequency40 class: 51 Hz50 class: 48 HzPower consumption(R1391)Refrigerant shortagezone
