F.49 — eBUS fault

What does F.49 mean?

A fault has occurred in the eBUS communication system, which connects the boiler to external controls and accessories. This can prevent proper communication.

• Short circuit detected on the eBUS line.
• eBUS system is overloaded with too many devices.
• Two power supplies with different polarities are connected to the eBUS.

Click steps to track your progress.

1. 1

   Press the fault clearance key on the boiler to reset it.

2. 2

   Check any recently installed eBUS accessories or controls for correct wiring.

3. 3

   If the fault persists, contact Vaillant Service Solutions, as specialist knowledge is required for eBUS diagnostics.