E109 — Pre-circulation alarm

What does E109 mean?

The boiler has detected an issue during the pre-circulation phase, which is when the pump runs before ignition to prepare the system.

• Blocked or jammed pump.
• Air present in the heating circuit.
• Insufficient water circulation.

Click steps to track your progress.

1. 1

   Turn off the main power supply to the boiler, wait 30 seconds, then turn it back on.

2. 2

   Ensure the system water pressure is within the recommended range (typically 1-1.5 bar).

3. 3

   If the error persists, a qualified technician should check the pump for proper operation and inspect the system for airlocks.