Check
SiUS331708EA
259
Service Diagnosis
5.3
Superheat Operation Check
Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points.
Notes:
∗
1: Refer to Low pressure protection control for hot gas bypass control on page 54.
∗
2: Refer to Subcooling electronic expansion valve control on page 43.
∗
3: Superheating temperature control in cooling is conducted by indoor unit electronic expansion valve.
∗
4: Superheating temperature control in heating is conducted by outdoor unit electronic expansion valve.
∗
5: Judgment criteria of superheat operation: (1) Suction gas superheated degree: 10°C (50°F) and
over. (2) Discharge gas superheated degree: 45°C (113°F) and over, except immediately after
compressor starts up or is running under dropping control.
(Use the above values as a guide. Depending on the other conditions, the unit may be normal
despite the values within the above range.)
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 service
monitor PCB
Defective main
PCB
Defective valve coil
Defective low
pressure sensor
Defective subcooling
heat exchanger outlet
thermistor
Defective valve
body
Defective
subcooling
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)
(
∗
2)
Compressor
overheat
Refrigerant
shortage
High pipe
resistance
Defective
superheated
degree
control.
[In cooling]
If the indoor unit
electronic
expansion valve is
throttled too much:
(
∗
3)
[In heating]
If the outdoor unit
electronic
expansion valve
excessively
throttled: (
∗
4)
Temperature
increase of
discharge
pipe
Defective
subcooling
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 gas pipe
thermistor of indoor unit
Defective thermistor for
indoor unit liquid pipe
Defective main
PCB
Defective low pressure
sensor
Defective suction pipe
thermistor
Defective 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?
Summary of Contents for RXSQ24TAVJU
Page 1: ...Service Manual SiUS331708EA RXSQ24 36 48 60TAVJU Heat Pump 60 Hz...
Page 290: ...Wiring Diagrams SiUS331708EA 277 Appendix RXSQ48TAVJU 3D109546A...
Page 291: ...SiUS331708EA Wiring Diagrams Appendix 278 RXSQ60TAVJU 3D109547A...
Page 295: ...SiUS331708EA Wiring Diagrams Appendix 282 FXZQ05 07 09 12 15 18TAVJU 3D110443A...
Page 298: ...Wiring Diagrams SiUS331708EA 285 Appendix FXEQ07 09 12 15 18 24PVJU 3D098557A...
Page 300: ...Wiring Diagrams SiUS331708EA 287 Appendix FXSQ05 07 09 12 15 18 24 30 36 48 54TAVJU 3D110467B...
Page 301: ...SiUS331708EA Wiring Diagrams Appendix 288 FXMQ07 09 12 15 18 24 30 36 48 54PBVJU 3D093209B...
Page 302: ...Wiring Diagrams SiUS331708EA 289 Appendix FXHQ12 24 36MVJU 3D048116C...
Page 303: ...SiUS331708EA Wiring Diagrams Appendix 290 FXAQ07 09 12 18 24PVJU 3D075354C...
Page 309: ...SiUS331708EA Wiring Diagrams Appendix 296 VAM1200GVJU 3D073270D...