BoilerFaultCodesVaillant S.58 Fault Code
Also written as S58 — same fault.
The Vaillant S.58 fault code means: your boiler has temporarily restricted its power output to protect itself, often while it waits for water temperatures to balance out.. It appears on 9 Vaillant models in our database.
Technical description: Burner modulation limitation. The burner modulation limitation is activated.
What causes the Vaillant S.58 fault?
This status occurs when the boiler detects that heat is building up too quickly or cannot be circulated away from the unit effectively. It physically limits its own power to prevent overheating, which is often caused by valves being closed on radiators or a pump that is struggling to push water through the system. Essentially, the boiler is waiting for the water temperature to stabilize before it resumes full operation.
This is more common during shoulder seasons like spring or autumn, when radiators are frequently turned off in individual rooms, reducing the overall flow of water the boiler can use.
DIY fix possible
Check that all radiator valves are fully open to allow heat to move away from the boilerEnsure the system pressure is between 1.0 and 1.5 bar on the digital displayWait up to 15 minutes for the status code to clear automatically as it is often part of normal operation
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Gas Safe Register →Vaillant models that show the S.58 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vaillant S.58 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026