SiUS371901EB
Check
Part 6 Service Diagnosis
416
Note(s)
Reference
4. Check
4.1 High
Pressure
Check
Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points.
CHECK 6
Refer to page 426.
CHECK 1
Short circuit
Rise in high
pressure
Local
pressure
rise
High pipe
resistance
Stop valve closed
Bent or crashed pipe
Clogging of foreign
materials
[In cooling]
If the outdoor unit electronic
expansion valve is throttled:
(
1.)
Defective outdoor
unit electronic
expansion valve
Defective indoor
unit electronic
expansion valve
Defective valve coil
Defective valve body
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 sensor
Defective outdoor
unit main PCB
Defective
high pressure
control
Defective valve coil
Defective valve body
[In heating]
If the indoor unit electronic
expansion valve excessively
throttled:
(
2.)
Defective
control
Defective high pressure sensor
Defective indoor unit
liquid pipe thermistor
[In cooling]
High suction
air
temperature
of the
condenser
[In heating]
High suction air
temperature of
outdoor unit
Short circuit
High outdoor air
temperature
High suction
air temperature
of indoor unit
High room
temperature
Defective suction air thermistor of indoor unit
High suction air temperature of outdoor unit
Defective outdoor air temperature thermistor of outdoor unit
Degradation
in condensing
capacity
Dirty condenser
Mixing of non-condensable gas
Decreased
airflow rate
Decreased
fan
output
Defective fan
motor
Defective outdoor unit
main PCB (Including
capacity setting)
High
airflow
passage
resistance
Dirty filter
Obstacle
Excessive refrigerant charging
Improper model selection [In heating]
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?
Is the pressure value checked with the Service Checker
corresponding to the measurement value of the pressure sensor?
Are the voltage characteristics normal?
Are the coil resistance and insulation normal?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Is the suction air temperature less than 43°C (109.4°F)?
Is the outdoor air temperature less than 43°C (109.4°F)?
Is the suction air temperature less than 27°C (80.6°F)?
Is the room temperature less than 27°C (80.6°F)?
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?
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?
Refer to
CHECK 6
.
Is the indoor unit too small compared to
the large-sized outdoor unit?
Defective outdoor
unit main PCB
Is the pressure value checked with the Service Checker
corresponding to the measurement value of
the pressure sensor?
Are the voltage characteristics normal?
∗
1. In cooling, it is normal if the outdoor unit electronic expansion valve (main) is fully open.
∗
2. In heating, the indoor unit electronic expansion valve is used for subcooling degree control.
Summary of Contents for REYQ72-432XAYCU
Page 455: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 448 REYQ144 168XATJU REYQ144 168XATJA 2D119206B ...
Page 457: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 450 REYQ144 168XAYDU REYQ144 168XAYDA 2D119208C ...
Page 461: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 454 FXZQ05 07 09 12 15 18TAVJU 3D110443A ...
Page 463: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 456 FXEQ07 09 12 15 18 24PVJU 3D098557A ...
Page 464: ...Wiring Diagrams SiUS371901EB 457 Part 7 Appendix FXDQ07 09 12 18 24MVJU C 3D050501C ...
Page 468: ...Wiring Diagrams SiUS371901EB 461 Part 7 Appendix FXHQ12 24 36MVJU 3D048116C ...
Page 469: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 462 FXAQ07 09 12 18 24PVJU 3D075354F ...
Page 475: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 468 VAM1200GVJU 3D073270D ...
Page 478: ...Wiring Diagrams SiUS371901EB 471 Part 7 Appendix BS6 8Q54TVJ 2D089122B ...
Page 479: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 472 BS10 12Q54TVJ 2D089121B ...
Page 481: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 474 BSF6 8Q54TVJ 2D123905A ...