Lockout High

Chaffoteaux Lockout Fault Code

Also written as LOCKOUT — same fault.

The Chaffoteaux Lockout fault code means: your boiler has stopped working because it cannot light its internal flame or keep it burning, which has triggered a safety shut-down.. It appears on 2 Chaffoteaux 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: Flame extinguishes: When the ionisation probe fails to detect flame presence. If a flame is not detected within 10 seconds, the safety solenoids will close. The red lockout indicator 35 illuminates and the display shows the error code.
Typical repair cost £120-250 (including labour)

Engineer required

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

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Chaffoteaux models that show the Lockout fault code

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

Source

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

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