Table of Contents
Check
3. Check
3.1
High Pressure Check
CHECK 1
Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points.
Rise in high
pressure
∗1. In cooling, it is normal if the outdoor unit electronic expansion valve (main) is fully open.
Notes:
∗2. In heating, the indoor unit electronic expansion valve is used for "subcooled degree control".
283
Local
High pipe
pressure
resistance
rise
[In cooling]
Defective outdoor
If the outdoor unit electronic
unit electronic
expansion valve is throttled:
expansion valve
(∗1)
A temperature difference in
excess of 10°C (18°F) between
the inlet and the outlet is deemed
to be abnormal.
Defective
control
Defective
high pressure
Defective indoor
control
unit electronic
expansion valve
[In heating]
Defective
If the indoor unit electronic
control
expansion valve excessively
throttled:
(∗2)
[In cooling]
High suction air
temperature of
High suction
outdoor unit
air
temperature
High suction
of the
condenser
air temperature
of indoor unit
Defective suction air thermistor of indoor unit
[In heating]
High suction air temperature of outdoor unit
Defective outdoor air thermistor of outdoor unit
Degradation
Dirty condenser
in condensing
capacity
Mixing of non-condensable gas
Decreased
airflow rate
Excessive refrigerant charging
Improper model selection [In heating]
←Check to be sure the stop valve is open.
Stop valve closed
←Conduct visual checks for pipe conditions.
Bent or crashed pipe
←Is there any temperature difference caused before
Clogging of foreign
and after the filter or branch pipe?
materials
←Are the coil resistance and insulation normal?
Defective valve coil
Defective valve body
←Are the electrical characteristics normal?
Defective high pressure sensor
Defective service
←Is the pressure value checked with the Service Checker
monitor PCB
corresponding to the measurement value of the pressure sensor?
←Are the coil resistance and insulation
Defective valve coil
normal?
Defective valve body
←Are the electrical characteristics normal?
Defective high pressure sensor
←Is the connector properly connected?
Defective indoor unit
Are the thermistor resistance characteristics normal?
liquid pipe thermistor
←Is the pressure value checked with the Service
Defective service
Checker corresponding to the measurement value of
monitor PCB
the pressure sensor?
←Is the suction air temperature less than 43°C (109.4°F)?
Short circuit
←Is the outdoor air temperature less than 43°C (109.4°F)?
High outdoor air
temperature
←Is the suction air temperature less than 27°C (80.6°F)?
Short circuit
High room
←Is the room temperature less than 27°C (80.6°F)?
temperature
←Is the connector properly connected?
Are the thermistor resistance characteristics normal?
←Is the outdoor air temperature less than 16°CWB (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?
Defective fan
Decreased
motor
fan
Defective
output
service monitor
PCB (Including
capacity setting)
High
Dirty filter
airflow
passage
resistance
Obstacle
←Refer to
CHECK 6
←Is the indoor unit too small compared to
the large-sized outdoor unit?
←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 airflow passage?
.
Service Diagnosis
SiUS341802E
- Quick Links:
- Outdoor Unit
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Troubleshooting
