Low
S.28 on Vaillant Home System

Your boiler has temporarily paused the burner because the water reaching the hot water tank is already hot enough and the system is waiting for the temperature to drop slightly before restarting.

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

Hot water handling mode: Temporary shutdown of the burner

From this model's manual
Verified against the Vaillant Home System installation & service manual, page 33.
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

Check that your hot water cylinder thermostat is not set too lowWait 10-15 minutes for the status code to change automaticallyEnsure your programmer is requesting hot water

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