Daikin B-Series Service Manual page 36

Si06-313
2.1.2 Cooling Only Model
A Outdoor Heat 1. The outdoor heat exchanger thermistor is used for controlling target discharge temperature.
Exchanger
Thermistor (DCB)
2. When cooling: an outdoor heat exchanger thermistor is used for detecting the discharge
3. The outdoor heat exchanger thermistor is used for high pressure protection during cooling
B Discharge 1. The discharge pipe thermistor is used to control the discharge pipe.
Pipe Thermistor
(DOT)
2. The discharge pipe thermistor is used for detecting the discharge thermistor disconnected.
C Indoor Heat 1. The indoor heat exchanger thermistor is used for controlling target discharge pipe
Exchanger
Thermistor (DCN)
2. The indoor heat exchanger thermistor is used to prevent freezing.
3. The indoor heat exchanger thermistor is used for anti-icing control.
Function and Control
A
B
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.
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.
operation.
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.
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.
During the cooling operation, if the temperature drops abnormally, the operating frequency
becomes lower, then the operation must be halted.
During the cooling operation, if the heat exchanger temperature in the room where operation
is halted becomes -1°C, or if the room temperature - heat exchanger in the room where
operation is halted becomes ≥ 10°C, it is assumed as icing.
Function of Main Structural Parts
Electrontic
expansion valve
C
Compressor
(R2828)
27