How much does it cost to fix Keston error code E12 to E22?

Typical repair cost for the Keston E12 to E22 fault is £250-£450 including labour.

E12 to E22 High

Keston E12 to E22 Fault Code

Q: What does the Keston E12 to E22 fault code mean?

Your boiler's internal computer has detected a technical software or hardware failure and can no longer manage the heating system safely.

Also written as E12TOE22 — same fault.

The Keston E12 to E22 fault code means: your boiler's internal computer has detected a technical software or hardware failure and can no longer manage the heating system safely.. It appears on 9 Keston models in our database.

Technical description: Control box errors – possible faulty control box

Typical repair cost £250-£450 (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 E12 to E22 fault code

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

Source

Keston E12 to E22 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 27 April 2026