Daikin FTKE25BVM, Service Manual

Page: 97 / 298

Function of Main Structural Parts Si12-411A
86 Function and Control
2.2 Function of Thermistor
2.2.1 Heat Pump Model
A Outdoor Heat
Exchanger
Thermistor
(DCB)
1. An outdoor heat exchanger thermistor is used for controlling a target discharge temperature.
Set a target discharge temperature depending on an outdoor and indoor heat exchanger
temperature.
Control the electronic expansion valve opening so that the target discharge temperature can
be obtained.
2. An outdoor heat exchanger thermistor is used for detecting a disconnected discharge pipe
thermistor when cooling.
When the temperature of the discharge piping is lower than the temperature of outdoor heat
exchanger, a disconnected discharge pipe thermistor can be detected.
B Discharge
Pipe Thermistor
(DOT)
1. Discharge pipe thermistor is used to control a 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 must be
halted.
2. A discharge pipe thermistor is used for detecting a disconnected discharge pipe thermistor.
C Gas Pipe
Thermistor
(DGN)
1. When cooling: a gas pipe thermistor is used for gas pipe isothermal control.
Control electronic expansion valve opening so that a gas pipe temperature in each room
becomes equal.
SV
D
2
Four-way valve
1
Compressor
3
Solenoid valve
EV
B
EV
C
EV
D
EV
A
Receiver
4
Expansion valve
A
B
C
D
E
(R2435)