Daikin RQYQ140-180PY1 Service Manual page 202

Troubleshooting by Remote Controller
CHECK 5
Check for causes of wet operation.
Referring to the Fault Tree Analysis (FTA) shown below, identify faulty points.
Refrigerant accumulation
Overcharge of refrigerant
[Cooling]
Indoor unit
electronic
expansion
valve opens
too much. (*1)
Faulty control
of superheated
degree
[Heating]
Wet operation
Outdoor unit
electronic
expansion
valve opens too
much. (*2)
Degraded
evaporation
capacity
*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 outdoor unit electronic expansion valve
(EV1).
*3: Guideline of superheated degree to judge as wet operation
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.)
193
Faulty indoor
unit electronic
expansion valve
Faulty control
Faulty outdoor
unit electronic
expansion valve
Faulty control
Dirty evaporator
Reduced
air quantity
Suction gas superheated degree: Not more than 3°C;
Faulty crankcase heater
Frequent ON/OFF of compressor
Faulty valve coil
Faulty valve body
Faulty indoor unit
gas pipe thermistor
Faulty indoor unit
liquid pipe thermistor
Faulty control PCB
Faulty valve coil
Faulty valve body
Faulty power pressure sensor
Faulty suction pipe thermistor
Faulty control PCB
←Does the heat exchanger get clogged?
Faulty fan motor
Reduced
fan output
Faulty control PCB
(including faulty
capacity setting)
Increased
Dirty filter
resistance
in air
passage
Obstacles
Discharge gas superheated degree: Not more than
SiBE341001
←Refer to information in the [Check 6]
section.
←Does the valve coil have normal
resistance and insulation?
(Refer to information in the [Check 11]
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 [Check 11]
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?
Troubleshooting