What does the Keston E 30 fault code mean?

Your boiler is struggling to move heat around your home because the water is not flowing efficiently between the heater and your radiators.

How much does it cost to fix Keston error code E 30?

Typical repair cost for the Keston E 30 fault is £120-250 including labour.

Difference between flow and return temperatures too high. Check circulation.

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

Sludge build-up — needs flushing, not bleeding.

Almost always a stuck diverter valve on combis.

Each noise points to a different fault.