C6 — Fan speed too low or fan defect

What does C6 mean?

The boiler's fan speed is too low, or there is a general fan defect. This can hinder proper combustion and flue gas exhaust.

• Defective fan motor.
• Faulty fan lead or connector.
• Obstruction in the fan or flue system.
• Control board issue.

Click steps to track your progress.

1. 1

   Power cycle the boiler by turning off the main power for 30 seconds and then restarting.

2. 2

   Ensure there are no visible blockages in the flue terminal outside the property.

3. 3

   Contact a Gas Safe registered engineer to check the fan, its connections, and potentially replace it.