SiBE18-821_C Troubleshooting for Outdoor Unit
Troubleshooting 423
7.35 Check for Outdoor Unit
7.35.1 Check for Causes of Rise in High Pressure
Check No.01 Referring to the Fault Tree Analysis (FTA) shown below, probe the faulty points.
A temperature
difference in excess of
10°C between the inlet
and the outlet is
deemed to be
abnormal.
Short-circuit
Rise in high
pressure
Local
pressure
rise
High pipe
resistance
Stop valve closed
Bent or crashed pipe
Clogging of foreign
particles
←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.
[In cooling]
If the outdoor unit electronic
expansion valve is throttled:
(See *1.)
Faulty outdoor
unit electronic
expansion valve
Faulty
indoor unit
electronic
expansion
valve
Faulty valve coil
Faulty valve body
←Are the coil resistance and insulation normal?
Faulty
control
Faulty high pressure
sensor
Faulty control PCB
←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?
Faulty
high
pressure
control
Faulty valve coil
Faulty valve body
[In heating]
If the indoor unit
electronic expansion
valve excessively
throttled: (See *2.)
Faulty
control
Faulty high pressure
sensor
Faulty indoor unit
liquid pipe thermistor
Faulty control PCB
←Are the electrical characteristics normal?
←In 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?
[In cooling]
High suction
air
temperature
of the
condenser
[In heating]
High suction air
temperature
of outdoor unit
Short-circuit
High ambient
temperature
←
Is the suction air temperature not more than
46°C?
←Is the outdoor temperature not more than
46°C?
High suction
air temperature
of indoor unit
High ambient
temperature
←Is the suction air temperature not more than
27°C?
←Is the indoor temperature not more than
27°C?
Faulty suction air thermistor of indoor unit
High suction air temperature of outdoor unit
Faulty outdoor temperature thermistor of outdoor unit
←
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?
Dirty condenser
Mixing of non-condensable gas
←Is the heat exchanger clogged? (In cooling)
←Is air or else mixed in the refrigerant system?
Decreased
fan airflow
rate
←
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?
Faulty control
PCB
(Including
capacity setting)
High air
passage
resistance
Dirty filter
←Is the air filter clogged?
Obstacle
←Is there any obstacle in the air passage?
Excessive refrigerant charging
Improper model selection
[In heating]
←Refer to troubleshooting "
F6".
←Is the indoor unit too small compared to
the large-sized outdoor unit?
*1:
In cooling, it is normal if the outdoor unit electronic expansion valve (Y1E) 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”.)
(R13055)
Degradation
in condensing
capacity
Decreased
fan
output
Faulty fan
motor
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