Daikin RQYQ140-180PY1 Service Manual page 198

Troubleshooting by Remote Controller
CHECK 1
Check for causes of rise in high pressure
Referring to the Fault Tree Analysis (FTA) shown below, probe the faulty points.
Local
pressure
rise
[In cooling]
If the outdoor unit electronic
expansion valve is throttled:
(See *1.)
Rise in high
pressure
Faulty high
pressure
control
[In heating]
If the indoor unit electronic
expansion valve is excessively
throttled:
(See *2.)
[In cooling]
High suction
air
temperature
of the
condenser
Degradation in
condensing
capacity
Excessive refrigerant charging
Improper model selection [In heating]
*1: In cooling, it is normal if the outdoor unit electronic expansion valve (EVM) is fully open.
*2: In heating, the indoor unit electronic expansion valve is used for "subcooled degree control".
(For details, refer to "Electronic Expansion Valve Control".)
189
High pipe
resistance
Faulty outdoor
unit electronic
expansion valve
A temperature di f ference i n excess of 10°C between the
i n l e t and the outl e t i s deemed to be abnormal .
Faulty
control
Faulty indoor
unit electronic
expansion valve
Faulty
control
High suction air
temperature of
indoor unit
High suction air
temperature of
indoor unit
Faulty suction air thermistor of indoor unit
[In heating]
High suction air temperature of outdoor unit
Faulty outdoor temperature thermistor of outdoor unit
Dirty condenser
Mixing of non-condensable gas
Decreased
fan airflow
rate
←
Stop valve closed
←
Bent or crashed pipe
←
Clogging of foreign
particles
←
Faulty valve coil
Faulty valve body
←
Faulty high pressure sensor
←
Faulty control PCB
←
Faulty valve coil
Faulty valve body
←
Faulty high pressure sensor
←
Faulty indoor unit
liquid pipe thermistor
←
Faulty control PCB
←
Short circuit
←
High ambient temperature
←
Short circuit
←
High ambient temperature
←
←
←
←
Is the heat exchanger clogged? (In cooling)
←
Is air or else mixed in the refrigerant system?
Faulty fan
motor
Decreased
fan output
Faulty control
PCB (Including
capacity
setting)
Dirty filter
High air
passage
resistance
Obstacle
←
Refer to "F6" troubleshooting.
←
Is the indoor unit too small compared to
the large-sized outdoor unit?
SiBE341001
Check to be sure the stop valve is open.
Conduct visual checks for pipe conditions.
Is there any temperature difference caused
before and after the filter or branch pipe.
Are the coil resistance and insulation normal?
Are the electrical characteristics normal?
Is the pressure value checked with the Service Checker
corresponding to the measurement of the pressure sensor?
Are the coil resistance and insulation
normal?
Are the electrical characteristics normal?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Is the pressure value checked with the
Service Checker corresponding to the
measurement of the pressure sensor?
Is the suction air temperature not more
than 43°C?
Is the outdoor temperature not more than 43°C?
Is the suction air temperature not more than 27°C?
Is the indoor temperature not more than 27°C?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Is the outdoor temperature not more than 16°CWB?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
←
Can the fan motor be rotated with hands?
Are the motor coil resistance and
insulation normal?
←
If a spare PCB is mounted, is the capacity
setting properly made?
←
Is the air filter clogged?
←
Is there any obstacle in the air passage?
Troubleshooting