Low
S.28 on Vaillant Turbomax Plus 828

Your boiler is taking a short temporary break to prevent the system from switching on and off too frequently, which protects the internal components and saves energy.

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

Anti cycling mode (warm start)

DIY fix possible

Wait up to 15 minutes for the timer to count downCheck that your room thermostat is turned up high enough to call for heatEnsure the pre-heat (Warm Start) function is not set to a temperature much higher than your actual needs

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