How much does it cost to fix Grant error code Lock-out?

Typical repair cost for the Grant Lock-out fault is £150-350 including labour.

Lock-out High

Grant Lock-out Fault Code

Q: What does the Grant Lock-out fault code mean?

Your boiler has stopped working because it failed to start the heating process, triggering a safety system that keeps the burner turned off.

Also written as LOCKOUT — same fault.

The Grant Lock-out fault code means: your boiler has stopped working because it failed to start the heating process, triggering a safety system that keeps the burner turned off.. It appears on 16 Grant models in our database.

Technical description: Burner does not light and the 'Lock-out' reset button lights.

Typical repair cost £150-350 (including labour)

Engineer required

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

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Grant models that show the Lock-out fault code

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

Source

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

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026