E 01 High

Keston E 01 Fault Code

Also written as E01 — same fault.

The Keston E 01 fault code means: your boiler is failing to start because it cannot light the internal flame needed to provide your heating and hot water.. It appears on 2 Keston models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Ignition failure - the boiler has attempted to light five times and not succeeded - check the gas supply is on.
Typical repair cost £150-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Keston models that show the E 01 fault code

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

Source

Keston E 01 fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026