How much does it cost to fix Keston error code E00?

Typical repair cost for the Keston E00 fault is £120-280 including labour.

E00 High

Keston E00 Fault Code

Q: What does the Keston E00 fault code mean?

Your boiler thinks it sees a flame even though it hasn't started the ignition process yet, which prevents it from running for safety reasons.

The Keston E00 fault code means: your boiler thinks it sees a flame even though it hasn't started the ignition process yet, which prevents it from running for safety reasons.. It appears on 7 Keston models in our database.

Technical description: Flame detected when not expected – check boiler earth and probe condition

Typical repair cost £120-280 (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 E00 fault code

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

Celsius 25 Repair: £120-£280
Celsius 30 Repair: £120-£250
Heat 45 Repair: £120-280
Heat 55 Repair: £120-£280
Heat 80 Repair: £120-280
System S30 Repair: £120-280
System S40 Repair: £120-280

Source

Keston E00 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