Service Manual
Table Of Contents
- Cover
- Table of contents
- Part 1 List of Functions
- Part 2 Specifications
- Part 3 Printed Circuit Board Connector Wiring Diagram
- Part 4 Refrigerant Circuit
- Part 5 Functions and Control
- Part 6 Test Operation and Field Settings
- Part 7 Remote Controller
- Part 8 Troubleshooting
- 1. Troubleshooting with LED
- 2. Service Diagnosis
- 3. Error Codes and Description
- 4. Troubleshooting for CTXG, CTXS, FTXS, CDXS, FDXS, FVXS Series
- 5. Troubleshooting for FFQ Series
- 6. Troubleshooting for Branch Provider (BP) Unit
- 7. Troubleshooting for Outdoor Unit
- 8. Thermistor Resistance/Temperature Characteristics
- 9. Pressure Sensor
- 10. Method of Replacing Inverter’s Power Transistors Modules
- Part 9 Appendix
Troubleshooting for Outdoor Unit SiUS181631EA
256 Troubleshooting
7.27 Signal Transmission Error between Indoor Unit and
Outdoor Unit in the Same System
Error Code
U9
Method of Error
Detection
Error Decision
Conditions
Supposed
Causes
Signal transmission error within system
Defective electronic expansion valve in indoor unit of other system
Defective indoor unit PCB in other system
Improper connection of transmission wiring between indoor and outdoor unit
Troubleshooting
Turn on all indoor units.
U9 has
been displayed for 2
minutes or more?
UA
blinks on the
other remote controllers
within the same
system?
A1
blinks on the
other remote controllers
within the same
system?
A9
blinks on the
other remote controllers
within the same
system?
U4
blinks on the
other remote controllers
within the same
system?
Re-diagnose by display after
passage of 2 minutes or
more.
Refer to troubleshooting for
UA
error code.
Refer to troubleshooting for
U5
error code.
(R19192)
YES
NO
NO
YES
Refer to troubleshooting for
A1
error code.
NO
YES
Refer to troubleshooting for
A9
error code.
NO
YES
Refer to troubleshooting for
U4
error code.
YES
NO
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.