Specifications

SiBE341027 Troubleshooting by Remote Controller
Service Diagnosis 183
Check for causes of wet operation.
Referring to the Fault Tree Analysis (FTA) shown below, identify defective points.
CHECK 5
[Cooling]
Indoor unit
electronic
expansion
valve opens
too much. (∗1)
[Heating]
Outside unit
electronic
expansion
valve opens too
much. (∗2)
Defective control
of superheated
degree
Defective indoor
unit electronic
expansion valve
Defective outside
unit electronic
expansion valve
Defective
control
Defective
control
←Refer to information in the
section.
←Does the valve coil have normal
resistance and insulation?
(Refer to information in the
section.)
←Is the connector correctly connected?
Are the thermistor resistance
characteristics normal?
←Is the connector correctly connected?
Are the thermistor resistance
characteristics normal?
←Does the valve coil have normal
resistance and insulation?
(Refer to information in the
section.)
←Are the voltage characteristics normal?
←Is the connector correctly connected?
Does the thermistor have normal
resistance characteristics?
←Is the pressure reading of the service
checker corresponding to the actual
measurement of the sensor?
←Can the fan motor be rotated by
hand?
Does the fan motor coil have
normal resistance and
insulation?
←Does the air filter get clogged?
←Are there any obstacles in the air
passage?
Degraded
evaporating
capacity
Increased
resistance
in air
passage
Reduced
air quantity
Reduced
fan output
∗1: "Superheated degree control" in cooling operation is exercised with the indoor unit electronic expansion valve.
∗2: "Superheated degree control" in heating operation is exercised with the outside unit electronic expansion valve
(EV1).
∗3: Guideline of superheated degree to judge as wet operation

Suction gas superheated degree: Not more than 3°C;

Discharge gas superheated degree: Not more than
15°C, except immediately after compressor starts up or is running under drooping control.
(Use the values shown above as a guideline. Even if the superheated degree falls in the range, the compressor
may be normal depending on other conditions.)
CHECK 11
CHECK 11
CHECK 6
Wet operation
Refrigerant accumulation
Overcharge of refrigerant
Defective crankcase heater
Frequent ON/OFF of compressor
Dirty evaporator
Defective valve coil
Defective valve body
Defective indoor unit
gas pipe thermistor
Defective indoor unit
liquid pipe thermistor
Defective service monitor PCB
Defective valve coil
Defective valve body
Defective power pressure sensor
Defective suction pipe thermistor
Defective service monitor PCB
←Does the heat exchanger get clogged?
Defective fan motor
Defective service monitor PCB
(including defective capacity
setting)
Dirty filter
Obstacles