Specifications
Table Of Contents
- Cover
- Table of Contents
- Part 1 General Information
- Part 2 Specifications
- Part 3 Refrigerant Circuit
- Part 4 Function
- Part 5 Test Operation
- Part 6 Troubleshooting
- Part 7 Appendix
- 1. Piping Diagrams
- 2. Wiring Diagrams for Reference
- 3. List of Electrical and Functional Parts
- 4. Option List
- 5. Piping Installation Point
- 6. Example of connection (R-410A Type)
- 7. Thermistor Resistance / Temperature Characteristics
- 8. Pressure Sensor
- 9. Method of Checking the Inverter’s Power Transistors and Diode Modules
- Part 8 Precautions for New Refrigerant (R-410A)
- Index
- Drawings & Flow Charts

Si34-704 Troubleshooting by Indication on the Remote Controller
Troubleshooting 271
3.46
“
U4
”
Malfunction of Transmission between Indoor Units
Remote
Controller
Display
U4
Applicable
Models
All model of indoor unit
RXQ5P~54P
Method of
Malfunction
Detection
Check if the transmission between indoor unit and outdoor unit is correctly executed using
microcomputer.
Malfunction
Decision
Conditions
When transmission is not carried out normally for a certain amount of time
Supposed
Causes
Indoor to outdoor, outdoor to outdoor transmission wiring F1, F2 disconnection, short circuit
or wrong wiring
Outdoor unit power supply is OFF
System address doesn’t match
Defect of indoor unit PC board
Defect of outdoor unit PC board