Function of Thermistor
SiBE12-908
37
Function and Control
2. Function of Thermistor
2.1
Heat Pump Model
A Outdoor Heat
Exchanger
Thermistor
1. The outdoor heat exchanger thermistor is used for controlling target discharge pipe
temperature.
The system sets a target discharge pipe temperature according to the outdoor and indoor
heat exchanger temperature, and controls the electronic expansion valve opening so that
the target discharge pipe temperature can be obtained.
2. The outdoor heat exchanger thermistor is used for detecting disconnection of the discharge
pipe thermistor when cooling.
When the discharge pipe temperature becomes lower than the outdoor heat exchanger
temperature, the discharge pipe thermistor is judged as disconnected.
3. The outdoor heat exchanger thermistor is used for high pressure protection during cooling
operation.
B Discharge
Pipe Thermistor
1. 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 pipe
thermistor.
C Gas Pipe
Thermistor
1. In cooling, the gas pipe thermistors are used for gas pipe isothermal control.
The system controls electronic expansion valve opening so that gas pipe temperature in
each room becomes equal.
(R7042)
Expansion valve
E
D
C
A
B
Four way valve
Compressor
EV
A
EV
B
