Daikin 2MKS40FV1B, Service Manual

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SiEN12-710A Main Functions
Function and Control 39
1.13 Function of Thermistor
1.13.1 Heat Pump Model
A Outdoor Heat
Exchanger
Thermistor 1. 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 heat
exchanger temperature, and controls the electronic expansion valve opening so that the
target discharge temperature can be obtained.
2. The outdoor heat exchanger thermistor is used for detecting disconnection of the discharge
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
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.
EV
B
EV
A
Four way valve
Compressor
Expansion valve
A
B
C
D
E
(R7042)