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SiUS30-1301
Troubleshooting by Indication on the Remote Controller
Service Diagnosis
241
3.51 Check
Check for Causes of Rise in High Pressure
Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points.
Note:
1: In cooling, it is normal if the condensing unit electronic expansion valve is fully open.
2: In heating, the indoor unit electronic expansion valve is used for
Subcooling Degree Control
.
(For details, refer to
Electronic Expansion Valve Control
.)
CHECK 1
Local
pressure
rise
[In cooling]
If the condensing unit
electronic expansion valve is
throttled: (See
1.)
Defective high
pressure
control
Rise in high
pressure
[In heating]
If the indoor unit electronic
expansion valve is excessively
throttled:
(See
2.)
High suction
air
temperature
of the
condenser
[In cooling]
[In heating]
Degradation
incondensing
capacity
Refrigerant overcharge
Improper model selection
[In heating]
High pipe
resistance
Defective condensing
unit electronic
expansion valve
A temperature difference in excess of 18°F between the
inlet and the outlet is deemed to be abnormal.
Defective
control
Defective indoor
unit electronic
expansion valve
Defective
control
High suction air
temperature of
indoor unit
High suction air
temperature of
indoor unit
Defective suction air thermistor of condensing
unit
High suction air temperature of
condensing
unit
Defective outdoor air temperature thermistor of
condensing unit
Dirty condensing
Mixing of non-condensable gas
Decreased
fan airflow
rate
Decreased
fan output
High air
passage
resistance
Defective
fan motor
Defective
control PCB
(Including
capacity setting)
Dirty filter
Obstacle
Stop valve closed
Bent or crashed pipe
Clogging of foreign particles
Defective valve coil
Defective valve body
Defective high pressure sensor
Defective control PCB
Defective valve coil
Defective valve body
Defective high pressure sensor
Defective indoor unit
liquid pipe thermistor
Defective control PCB
Short circuit
High outdoor air temperature
Short circuit
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 109.4°F?
Is the outdoor air temperature not more
than 109.4°F?
Is the suction air temperature not more
than 80.6°F?
Is the indoor air temperature not more than 80.6°F?
Is the connector properly connected?
Are the thermistor resistance
characteristics normal?
Is the outdoor air temperature not more
than 60.8°FWB?
Is the connector properly connected?
Are the thermistor resistance
characteristics normal?
Is the heat exchanger clogged? (In cooling)
Is air or else mixed in the refrigerant system?
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?
Refer to “
F6
” troubleshooting.
Is the indoor unit too small compared to
the large-sized condensing unit?
High outdoor air temperature
High outdoor air temperature