Daikin RMXS-L Series User Manual

Troubleshooting for Branch Provider (BP) Unit SiUS181631EA
222 Troubleshooting
6.4 Signal transmission Error between Indoor Unit and
Branch Provider (BP) Unit
Error Code
U4
Method of Error
Detection
The signal transmission data from the BP unit is checked whether it is normal.
Error Decision
Conditions
When the data sent from the BP unit cannot be received normally, or when the content of the data
is abnormal.
Supposed
Causes

Defective BP unit PCB

Defective indoor unit PCB

Signal transmission error due to wiring error

Signal transmission error due to disturbed power supply waveform

Signal transmission error due to breaking of connection wires (wire No. 2)

Daikin RMXS-L Series Specifications

General

Brand	Daikin
Model	RMXS-L Series
Category	Heat Pump
Language	English

Summary

Part 1 List of Functions

Part 2 Specifications

1.1 Outdoor Unit

Provides detailed specifications for the outdoor unit, including capacity, dimensions, and electrical data.

1.3 Indoor Unit

Part 4 Refrigerant Circuit

1.1 Outdoor Unit

1.2 Branch Provider (BP) Unit

3. Refrigerant Flow for Each Operation Mode

Diagrams illustrating refrigerant flow during cooling, heating, and oil return operations.

Part 5 Functions and Control

1. Operation Mode

2. Basic Control

3. Special Control

4. Protection Control

Covers critical protection controls for high/low pressure, temperature, inverter, freeze-up, and condensation.

6. Branch Provider (BP) Unit Control

Part 6 Test Operation and Field Settings

1. Test Operation

Provides procedures for initial test operation, including power checks and operation verification.

2. Field Settings

Details procedures for configuring field settings on outdoor units and remote controllers.

Part 8 Troubleshooting

1. Troubleshooting with LED

Guides troubleshooting using LED indicators on outdoor unit and service PCBs for error identification.

2. Service Diagnosis

Outlines service diagnosis procedures for various indoor unit series using remote controllers and error codes.

3. Error Codes and Description

Comprehensive list of error codes with descriptions and reference pages for troubleshooting specific issues.

4. Troubleshooting for CTXG, CTXS, FTXS, CDXS, FDXS, FVXS Series

Provides specific troubleshooting steps for errors found in CTXG, CTXS, FTXS, CDXS, FDXS, FVXS series.

5. Troubleshooting for FFQ Series

Offers troubleshooting steps for errors specific to FFQ Series indoor units, covering PCB, motor, and sensor issues.

6. Troubleshooting for Branch Provider (BP) Unit

Details troubleshooting procedures for the Branch Provider (BP) unit, including expansion valve and PCB abnormalities.

7. Troubleshooting for Outdoor Unit

Covers troubleshooting for outdoor unit issues like PCB abnormalities, sensors, compressor, and fan motor problems.