BoilerFaultCodes.com
S.01 Low Information

Your boiler is currently preparing its internal fan to safely start the heating process.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Fan running

What causes this fault?

This status occurs when the boiler begins its ignition sequence and initiates the fan to clear out the combustion chamber. It is a normal part of the start-up process and indicates that the control board is successfully communicating with the fan motor. If the display stays on this code for a long time, it may suggest the fan is struggling to reach the speed required to proceed to the next step.

Typical repair cost £0 (including labour)

DIY fix possible

Check if the room thermostat is turned up to signal for heatWait up to 2 minutes for the boiler to complete its pre-ignition safety checksEnsure there is power to the boiler and the display is active

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