Low
S.20 on Vaillant Turbomax Plus 828

Your boiler is temporarily pre-heating its internal water tank to ensure you get hot water quickly when you turn on the tap.

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

Warmstart demand (warm start)

From this model's manual
Verified against the Vaillant Turbomax Plus 824 828e installation & service manual, page 38.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

No action is required as this is a normal operational status message.If you wish to stop this from happening, turn the 'Comfort' or 'Warmstart' dial to the 'off' position.Check your user manual to see how to disable the pre-heat function if you prefer to save energy.

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