Low
S.11 on Vaillant ecoTEC Pro / ecoTEC Plus System

Your boiler is currently attempting to start up its fan to prepare for heating your hot water, which is a normal part of the ignition process.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

DHWmode:Fanstart-up

From this model's manual
Verified against the Vaillant Ecotec Pro Ecotec Plus System installation & service manual, page 59.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's control board sends a signal to the fan to begin spinning, but the fan fails to respond or reach the required speed. The most common reasons are a physical blockage in the fan's blades, a loose internal electrical connection, or a failure in the fan's motor and electronics.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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S.10View →S.12View →F.32View →

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