LOCKOUT High

Warmworld LOCKOUT Fault Code

The Warmworld LOCKOUT fault code means: your boiler has shut down because its exhaust system has become too hot, which is a safety feature to prevent damage or dangerous fumes.. It appears on 1 Warmworld model 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: The flue thermostat will trip if the flue exceeds a preset temperature.
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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Warmworld models that show the LOCKOUT fault code

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

Source

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

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