SiUS04-702 Function of ThermistorFunction and Control 332. Function of Thermistor2.1 Heat Pump ModelA Outdoor HeatExchangerThermistor1. The outdoor heat exchanger thermistor is used for controlling target discharge temperature.The system sets a target discharge temperature according to the outdoor and indoor heatexchanger temperature, and controls the electronic expansion valve opening so that the targetdischarge temperature can be obtained.2. The outdoor heat exchanger thermistor is used for detecting disconnection of the dischargethermistor when cooling.When the discharge pipe temperature becomes lower than the outdoor heat exchangertemperature, the discharge pipe thermistor is judged as disconnected.3. The outdoor heat exchanger thermistor is used for high pressure protection during coolingoperation.B DischargePipe Thermistor1. The discharge pipe thermistor is used for controlling temperature of the discharge pipe.If the temperature of discharge pipe (used in place of the inner temperature of the compressor)rises abnormally, the operating frequency drops or the operation halts.2. The discharge pipe thermistor is used for detecting disconnection of the discharge thermistor.C Indoor HeatExchangerThermistor1. The indoor heat exchanger thermistor is used for controlling target discharge temperature.The system sets a target discharge pipe temperature according to the outdoor and indoor heatexchanger temperature, and controls the electronic expansion valve opening so that the targetdischarge temperature can be obtained.2. The indoor heat exchanger thermistor is used for preventing freezing.During the cooling operation, if the temperature drops abnormally, the operating frequencybecomes lower, then the operation halts.3. During heating: the indoor heat exchanger thermistor is used for detecting disconnection of thedischarge pipe thermistor.When the discharge pipe temperature becomes lower than the indoor heat exchangertemperature, the discharge pipe thermistor is judged as disconnected.The indoor heat exchanger thermistor is also used for preventing abnormal high pressure.Four way valveCompressor (R5204)ACBElectronticexpansion valve
