How much does it cost to fix Keston error code CONDITION 1?

Typical repair cost for the Keston CONDITION 1 fault is £120-350 including labour.

CONDITION 1 High

Keston CONDITION 1 Fault Code

Q: What does the Keston CONDITION 1 fault code mean?

Your boiler has detected a fault and has safely shut itself down to prevent damage, leaving you without heating and hot water.

Also written as CONDITION1 — same fault.

The Keston CONDITION 1 fault code means: your boiler has detected a fault and has safely shut itself down to prevent damage, leaving you without heating and hot water.. It appears on 1 Keston model in our database.

Technical description: Red light on the instrument panel on (shut down signal)

Typical repair cost £120-350 (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 CONDITION 1 fault code

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

R-sm 20 FB Repair: £120-350

Source

Keston CONDITION 1 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