No communication betw. system controller and remote control — Room sensor error A21-A24

What does 1001/A2x mean?

The room sensor displays an error code (A21, A22, A23, or A24) because the EMS bus signal has gone absent from the parent controller (display HMC300/HPC400) after successful installation.

• Poor EMS connection between the display and the installer module.

Click steps to track your progress.

1. 1

   Check both ends of the EMS cabling connections between the display (HMC300/HPC400) and the installer module boards.

2. 2

   Ensure all connections are secure and properly seated.

3. 3

   If the problem persists, contact a qualified installer to inspect the cabling for damage or interference.