Check
SiUS371901EB
419
Part 6 Service Diagnosis
Note(s)
4.3 Superheat Operation Check
Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points
CHECK 3
Abnormal piping length
Bent or crashed pipe
(Including moisture choke)
Stop valve closed.
Defective valve coil
Defective valve body
Defective valve coil
Defective valve body
Are the coil resistance and insulation normal?
Refer to
CHECK 7 .
Does the piping length fall in the permissible range?
Conduct visual checks.
Eliminate moisture by vacuum operation. (Refer to
CHECK 8 .
)
Check if the stop valve is open.
Defective
discharge
pipe
temperature
control
Defective hot
gas bypass
control
Hot gas circuit clogging
Defective solenoid
valve coil
Defective solenoid
valve body
Defective outdoor unit
main PCB
Defective outdoor
unit main PCB
Defective valve coil
Defective low
pressure sensor
Defective subcooling
heat exchanger outlet
thermistor
Defective valve
body
Defective
injection
electronic
expansion
valve control
Superheat due to
shaft damage
Superheat due to
defective compressor
Defective indoor
unit electronic
expansion valve
Defective
control
Defective
control
Defective
outdoor unit
electronic
expansion valve
Defective four
way valve
operation
[In cooling only]
(
1)
Compressor
overheat
Refrigerant
shortage
High pipe
resistance
Defective
superheating
degree
control.
[In cooling]
If the indoor unit
electronic
expansion valve is
throttled too much:
(
2)
[In heating]
If the outdoor unit
electronic
expansion valve
excessively
throttled: (
3)
Temperature
increase of
discharge
pipe
Defective
injection
electronic
expansion
valve
Are the coil resistance and
insulation normal?
Is the connector properly connected?
Are the thermistor resistance characteristics
normal?
Are the voltage characteristics normal?
Is the pressure value checked with the
Service Checker corresponding to the
measurement value of the pressure sensor?
Check if the piping temperature connected
to the four way valve is normal.
Four way valve is in the
middle position.
Leak from hot gas bypass
valve
Defective
control
Defective thermistor for
indoor unit gas pipe
Defective thermistor for
indoor unit liquid pipe
Defective indoor
unit control PCB
Defective low pressure
sensor
Defective suction pipe
thermistor
Defective outdoor
unit main PCB
Are the voltage characteristics normal?
Is the pressure value checked with the Service
Checker corresponding to the measurement
value of the pressure sensor?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Are the coil resistance and insulation normal?
Are the coil resistance and insulation normal?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
∗
1. Refer to Low pressure protection control for hot gas bypass control.
∗
2. Superheating temperature control in cooling is conducted by indoor unit electronic
expansion valve.
∗
3. Superheating temperature control in heating is conducted by outdoor unit electronic
expansion valve (main).
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 ...