How to wire the fresh air system to the distribution box

To wire a fresh air system to the distribution box, connect the sensor harness and power supply according to the manufacturer's instructions, ensuring proper grounding, secure connections, and adherence to airflow limits.

Step-by-Step Wiring Procedure

1. Power Off and Safety Before starting, turn off the main power supply to prevent electric shock or fire hazards. Ensure all personnel use proper safety equipment and follow local electrical codes . 2. Access the Control Box

• Remove the control box lid of the indoor unit or distribution box.
• Identify the existing sensor connectors (e.g., X16A on the indoor unit PCB and X4A on the adapter PCB for Daikin systems), . 3. Install Sensor Assembly
• Mount the sensor assembly and bell mouth on the indoor unit using the provided screws.
• Connect the sensor wire harness to the corresponding connectors on the PCB: X16A on the indoor unit and X4A on the adapter.
• Secure the harness with clamps to prevent movement or interference with other components . 4. Duct Connection
• Connect the fresh air duct to the connecting chamber of the indoor unit.
• Use bands and tape to seal the connection and prevent air leaks.
• Insulate the duct to avoid condensation.
• Hang and fix any T-tube sections as required . 5. Power Wiring
• Route the power supply wire from the circuit breaker or fuse box to the distribution box.
• Use a listed/certified cable with proper grounding.
• Strip insulation carefully and connect wires to the designated terminals on the distribution box or control board, following the manufacturer's polarity and voltage specifications . 6. Integration with Control Systems
• If the system includes a thermostat or control board, connect the communication or control cables according to the wiring diagram.
• Avoid using furnace 12 V wires for AC control unless explicitly approved . 7. Testing
• After wiring, restore power and perform a trial operation.
• Check for proper airflow, sensor readings, and absence of abnormal noises or leaks.
• Adjust the fresh air intake volume to remain within the recommended percentage of the indoor unit's rated airflow (typically 10–20%), . 8. Final Securing
• Replace the control box lid.
• Ensure all wires are clamped and routed safely to prevent contact with moving parts or sharp edges.
• Confirm that the duct and sensor assembly are firmly mounted . Following these steps ensures a safe, functional, and efficient connection of the fresh air system to the distribution box, maintaining proper airflow and sensor operation while preventing condensation or electrical hazards.