S.07 Low

Vaillant S.07 Fault Code

Also written as S07 — same fault.

The Vaillant S.07 fault code means: your boiler is briefly running the pump after the heating has switched off to cool the system down, but it is taking longer than expected to move the residual heat away.. It appears on 31 Vaillant models in our database.

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: Heating mode – pump overrun error

What causes the Vaillant S.07 fault?

This issue occurs when heat is trapped inside the boiler's heat exchanger after the heating has turned off, usually because the water isn't moving away quickly enough. The most common reasons are a pump that is beginning to fail, trapped air in the unit, or a build-up of sludge in the system pipes that is restricting flow.

This fault often appears at the start of autumn when the heating is turned back on after a long summer break, as pumps can seize or struggle after being idle for several months.

Typical repair cost £100-280 (including labour)

DIY fix possible

Check that at least one radiator (usually the one in the hallway near the thermostat) is fully turned on at the valves.Ensure the boiler pressure is within the green zone (typically 1.0 to 1.5 bar).Bleed your radiators to ensure there is no trapped air in the system.If the code persists, try resetting the boiler once to clear the status.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Vaillant models that show the S.07 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vaillant S.07 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