Branch Box LED 402 blinks 4 times — Serial communication error between branch boxes.

What does LED 402 (4) mean?

LED 402 flashes four times, specifically indicating a serial communication problem between different branch boxes in a multi-zone system.

• Loose or incorrect communication wiring between branch boxes.
• Interference affecting the communication lines between branch boxes.

Click steps to track your progress.

1. 1

   Reset the power to all branch boxes by cycling their circuit breakers.

2. 2

   Check all communication wiring connections between the branch boxes for any looseness, damage, or improper installation.

3. 3

   Ensure wiring is securely connected and routing is correct as per installation guidelines.

4. 4

   If the error persists, professional service is needed to diagnose the communication line.