Daikin RXYQ96PYDN Service Manual page 482

SiUS34-801A_b
[Check 10] Check for causes of wet operation.
Referring to the Fault Tree Analysis (FTA) shown below, identify faulty points.
[Cooling]
Indoor unit
motorized valve
opens too
much. (*1)
[Heating]
Wet operation
Outdoor unit
motorized valve
opens too
much. (*2)
*1: "Superheated degree control" in cooling operation is exercised with the indoor unit motorized valve.
*2: "Superheated degree control" in heating operation is exercised with the outdoor unit motorized valve (EV1).
*3: Guideline of superheated degree to judge as wet operation
Troubleshooting
Refrigerant accumulation
Overcharge of refrigerant
Faulty indoor
unit motorized
valve
Faulty control
Faulty control
of superheated
degree
Faulty outdoor
unit motorized
valve
Faulty control
Dirty evaporator
Degraded
evaporation
capacity
Reduced
air quantity
(Refer to information on P47, 195.)
Suction gas superheated degree: Not more than 5.4°F;
27°F, 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.)
Troubleshooting (OP: Unified ON/OFF Controller)
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 PC board
Faulty valve coil
Faulty valve body
Faulty power pressure sensor
Faulty suction pipe thermistor
Faulty control PC board
←Does the heat exchanger get clogged?
Faulty fan motor
Reduced
fan output
Faulty control PC board
(including faulty
capacity setting)
Increased
Dirty filter
resistance
in air
passage
Obstacles
Discharge gas superheated degree: Not more than
←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?
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