5 pulses (blue light) — Volatile lockout (sensor, fan, or code plug issue)

What does 5 pulses mean?

The blue indicator light displays 5 pulses, indicating a volatile lockout related to a sensor, the fan, or the code plug. This is a general electronic fault.

• A faulty temperature sensor or its wiring/connections
• A malfunctioning fan or its cable/connections
• An incorrectly fitted code plug
• The service mode switch being left in the minimum or maximum position

Click steps to track your progress.

1. 1

   Reset the boiler using the user control panel.

2. 2

   If you have recently had work done, ensure the code plug (if applicable) is correctly fitted.

3. 3

   Check that any accessible service mode switches are in the normal operating position.

4. 4

   If the issue persists, contact a qualified service engineer to diagnose sensor, fan, or control board components.