Low
S.46 on Vaillant Home System

Your boiler is temporarily running at its lowest power setting to prevent it from overheating while it waits for the system temperature to drop.

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

Protection mode: Minimum load

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 at least two or three radiators are turned on fullyEnsure thermostatic radiator valves (TRVs) are not all set to 'zero'Check that the boiler pressure is between 1.0 and 1.5 bar on the display

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