What does the Keston E31 fault code mean?

Your boiler has lost the signal from the sensor that monitors the flow of water, meaning it cannot confirm if the system is safe to fire up.

How much does it cost to fix Keston error code E31?

Typical repair cost for the Keston E31 fault is £150-250 including labour.

Flow sensor open circuit - check connections to flow sensor are in place

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Almost always a stuck diverter valve on combis.

Safety-critical — turn off, read this.

7 signs repair isn't worth it anymore.