Thermistor Functions - Daikin FTK Series Service Manual

DAMA-SM-21-001

2. Thermistor Functions

(A)FTXC series only
(3) Outdoor
Temperature
Thermistor
(1) Discharge Pipe
(1) Discharge
 The discharge pipe thermistor is used for controlling discharge pipe temperature. If the
Pipe Thermistor
 The discharge pipe thermistor is used for detecting disconnection of the discharge pipe
(2) Outdoor Heat
 The outdoor heat exchanger thermistor is used for controlling the target discharge pipe
Exchanger
Thermistor
 In cooling operation, the outdoor heat exchanger thermistor is used for detecting the
 In cooling operation, the outdoor heat exchanger thermistor is used for high pressure
(3) Outdoor
 The outdoor temperature thermistor detects the outdoor air temperature and is used for
Temperature
Thermistor
(4) Indoor Heat
 The indoor heat exchanger thermistor is used for controlling the target discharge pipe
Exchanger
Thermistor
 In cooling operation, the indoor heat exchanger thermistor is used for freeze-up protection
 During heating, the indoor heat exchanger thermistor is used for detecting disconnection of
(5) Room
 The room temperature thermistor detects the room air temperature and is used for
Temperature
Thermistor
Functions and Control
(2) Outdoor Heat
Exchanger
Thermistor
Four way valve
Compressor
Temperature
discharge pipe temperature (used in place of the inner temperature of the compressor) rises
abnormally, the operating frequency becomes lower or the operation halts.
thermistor.
temperature. The system sets the 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.
disconnection of the discharge pipe thermistor. When the discharge pipe temperature drops
below the outdoor heat exchanger temperature by more than a certain value, the discharge
pipe thermistor is judged as disconnected.
protection.
refrigerant shortage detection, input current control, outdoor fan control, liquid compression
protection function, and so on.
temperature. The system sets the 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.
control. If the indoor heat exchanger temperature drops abnormally, the operating frequency
becomes lower or the operation halts.
the discharge pipe thermistor.
When the discharge pipe temperature becomes lower than the indoor heat exchanger
temperature, the discharge pipe thermistor is judged as disconnected.
The indoor heat exchanger thermistor is also used for preventing abnormal high pressure.
controlling the room air temperature.
(5) Room
Temperature
Thermistor
Expansion valve
(4) Indoor Heat
Exchanger
Thermistor

Thermistor Functions

33