Daikin RTSQ20PY1 Service Manual page 358

Troubleshooting (Heat Reclaim Ventilation)
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
[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.
(Refer to information on P.127.)
*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
(1)Suction gas superheated degree: Not more than 3°C; (2)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.)
347
Faulty crankcase heater
Frequent ON/OFF of compressor
Faulty valve coil
Faulty indoor
unit electronic
expansion valve
Faulty valve body
Faulty indoor unit
gas pipe thermistor
Faulty control
Faulty indoor unit
liquid pipe thermistor
Faulty control PCB
Faulty valve coil
Faulty outdoor
unit electronic
expansion valve
Faulty valve body
Faulty power pressure sensor
Faulty suction pipe thermistor
Faulty control
Faulty control PCB
Dirty evaporator
Reduced
fan output
Reduced
air quantity
Increased
resistance
in air
passage
←
Refer to
CHECK 11
← Does the valve coil have normal
resistance and insulation?
(Refer to P.408.)
← 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 P.408.)
← Are the voltage characteristics normal?
← Is the connector correctly connected? ← Is the connector correctly connected?
Does the thermistor have normal Does the thermistor have normal
resistance characteristics? resistance characteristics?
← Is the pressure reading of the service
checker corresponding to the actual
measurement of the sensor?
← Does the heat exchanger get clogged?
← Can the fan motor be rotated by
Faulty fan motor
hand?
Does the fan motor coil have
normal resistance and
Faulty control PCB insulation?
(including faulty
capacity setting)
← Does the air filter get clogged?
Dirty filter
← Are there any obstacles in the air
Obstacles
passage?
SiBE31-801_C
.
Troubleshooting