Grant Lock-out (Red neon) Fault Code
Also written as LOCKOUTREDNEON — same fault.
The Grant Lock-out (Red neon) fault code means: your boiler has stopped working because the flame inside failed to light or stay on.. It appears on 1 Grant model in our database.
Technical description: Burner has failed to ignite or flame has been lost. Press the reset button on the burner control box if it is lit.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Grant models that show the Lock-out (Red neon) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Grant Lock-out (Red neon) 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