Your boiler is continuing to run its internal pump for a short period after heating your water to ensure it cools down safely and efficiently.

Pump overrun time after warm start

What causes this fault?

This is a normal operational feature rather than a mechanical failure. It occurs when the boiler keeps the internal pump running for a few minutes after heating your water to move residual heat away from the heat exchanger and protect the internal components. This prevents the boiler from overheating and ensures it stays in good condition for its next use.