Troubleshooting by Error Codes
SiUS281811EA
280
Part 6 Service Diagnosis
4.50 Transmission Error between Indoor Units and Outdoor
Units
Error Code
U4
Applicable
Models
All indoor and outdoor units
Method of Error
Detection
Microcomputer checks if transmission between indoor and outdoor units is normal.
Error Decision
Conditions
When transmission is not carried out normally for a certain amount of time
Supposed
Causes
Indoor to outdoor transmission wiring F1, F2 disconnection, short circuit or wrong wiring
Outdoor unit power supply is OFF
System address does not match
Defective indoor unit PCB
Defective outdoor main PCB
Troubleshooting
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Caution
YES
NO
All indoor
unit remote controllers
of the same refrigerant system
display
U4
.
Are the
indoor-outdoor unit
transmission wirings
normal?
Has the
indoor or outdoor
unit PCB been
replaced, or has the
indoor-outdoor unit
transmission wiring
been modified?
NO
YES
Replace the indoor unit PCB
indicated by the error code
U4
.
Fix the indoor-outdoor
unit transmission wiring.
NO
YES
Reset the power supply.
Press and hold the
RESET
(BS5)
button on the master
outdoor unit PCB for 5 seconds.
∗
The unit will not operate for
up to 12 minutes.
A
Go to the next page.
Содержание SkyAir RZR-TA Series
Страница 1: ...Service Manual Cooling Only 60 Hz Heat Pump 60 Hz RZR TA RZQ TA Series SiUS281811EA...
Страница 202: ...SiUS281811EA 196 Part 6 Service Diagnosis 5 15 Fan Motor Connector Check for FTQ TA 311...
Страница 321: ...SiUS281811EA 315 Part 7 Appendix 1 Wiring Diagrams 316 1 1 Outdoor Unit 316 1 2 Indoor Unit 320 Part 7 Appendix...
Страница 322: ...Wiring Diagrams SiUS281811EA 316 Part 7 Appendix 1 Wiring Diagrams 1 1 Outdoor Unit RZR18 24TAVJU RZQ18 24TAVJU 3D115455...
Страница 323: ...SiUS281811EA Wiring Diagrams Part 7 Appendix 317 RZR18 24TAVJUA RZQ18 24TAVJUA 3D124495...
Страница 324: ...Wiring Diagrams SiUS281811EA 318 Part 7 Appendix RZR30 36 42 48TAVJU RZQ30 36 42 48TAVJU 3D115456...
Страница 325: ...SiUS281811EA Wiring Diagrams Part 7 Appendix 319 RZR30 36 42 48TAVJUA RZQ30 36 42 48TAVJUA 3D124500...
Страница 326: ...Wiring Diagrams SiUS281811EA 320 Part 7 Appendix 1 2 Indoor Unit FCQ18 24 30 36 42 48TAVJU 3D115647A...
Страница 327: ...SiUS281811EA Wiring Diagrams Part 7 Appendix 321 FHQ18 24 30PVJU FHQ36 42MVJU 3D048116C...
Страница 328: ...Wiring Diagrams SiUS281811EA 322 Part 7 Appendix FAQ18 24TAVJU 3D114844B...
Страница 329: ...SiUS281811EA Wiring Diagrams Part 7 Appendix 323 FBQ18 24 30 36 42 48PVJU 3D065984J...