Daikin VRV III REYQ8PY1, Service Manual

Page: 366 / 452

Si37-701 Troubleshooting (OP: Unified ON/OFF Controller)
Troubleshooting 355
[Check 10] Check for causes of wet operation.
Referring to the Fault Tree Analysis (FTA) shown below, identify faulty points.
Refrigerant accumulation
Overcharge of refrigerant
Faulty crankcase heater
Frequent ON/OFF of compressor
[Cooling]
Indoor unit
motorized valve
opens too
much. (*1)
[Heating]
Outdoor unit
motorized valve
opens too
much. (*2)
Faulty control
of superheated
degree
Faulty indoor
unit motorized
valve
Faulty outdoor
unit motorized
valve
Faulty control
Faulty control
Faulty valve coil
Faulty control PC board
Faulty valve body
Faulty valve coil
Faulty valve body
Faulty power pressure sensor
Faulty suction pipe thermistor
Faulty control PC board
Faulty indoor unit
gas pipe thermistor
Faulty indoor unit
liquid pipe thermistor
←
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?
Wet operation
Degraded
evaporation
capacity
Increased
resistance
in air
passage
Dirty evaporator
Reduced
air quantity
Reduced
fan output
*1: "Superheated degree control" in cooling operation is exercised with the indoor unit motorized valve. (Refer to
information on P141.)
*2: "Superheated degree control" in heating operation is exercised with the outdoor unit motorized valve (EV1).
(Refer to information on P108.)
*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.)
Faulty fan motor
Dirty filter
Obstacles
Faulty control PC board
(including faulty
capacity setting)
←
Does the heat exchanger get clogged?