Fault A3 - Bus communication problem with Cascade Control

What does A3 mean?

This fault indicates a bus communication problem, specifically with the Cascade Control system, which manages multiple boilers.

• Improper connection of the X5 plug wire
• Defective boiler control or Cascade Control unit

Click steps to track your progress.

1. 1

   Check the wire connected to the X5 plug for proper and secure connection.

2. 2

   If the connection is secure, inspect the Cascade Control unit for any visible issues.

3. 3

   If the problem persists, the boiler control or Cascade Control unit may be defective and require professional attention.