Daikin ARK25BVMB, Service Manual

Page: 53 / 201

Function of Main Structural Parts SiBE04-302
44 Function and Control
2.2.2 Cooling Only Model
A Outdoor Heat
Exchanger
Thermistor
(DCB)
1. The outdoor heat exchanger thermistor is used for controlling target discharge temperature.
Set a target discharge temperature depending on the outdoor and indoor heat exchanger
temperature.
Control the electronic expansion valve opening so that the target discharge temperature can
be obtained.
2. When cooling: an outdoor heat exchanger thermistor is used for detecting the discharge
thermistor disconnected.
When the temperature of the discharge piping is lower than the temperature of outdoor heat
exchanger, a disconnected discharge thermistor can be detected.
3. The outdoor heat exchanger thermistor is used for high pressure protection during cooling
operation.
B Discharge
Pipe Thermistor
(DOT)
1. The discharge pipe thermistor is used to control 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 must be
halted.
2. The discharge pipe thermistor is used for detecting the discharge thermistor disconnected.
C Indoor Heat
Exchanger
Thermistor
(DCN)
1. The indoor heat exchanger thermistor is used for controlling target discharge pipe
temperature.
Set a target discharge pipe temperature according to the outdoor and indoor heat exchanger
temperature.
Control the electronic expansion valve opening so that the target discharge pipe
temperature can be obtained.
2. The indoor heat exchanger thermistor is used to prevent freezing.
During the cooling operation, if the temperature drops abnormally, the operating frequency
becomes lower, then the operation must be halted.
3. The indoor heat exchanger thermistor is used for anti-icing control.
During the cooling operation, if the heat exchanger temperature in the room where operation
is halted becomes -1°C, it is assumed as icing.
A
C
B
Compressor
(R2828)