BoilerFaultCodesIdeal Lock-out Fault Code
Also written as LOCKOUT — same fault.
The Ideal Lock-out fault code means: your boiler has failed to start after several automated attempts and has safely shut itself down to prevent a gas build-up.. It appears on 3 Ideal models in our database.
Technical description: 5 attempts at ignition, with 1 minute intervals between attempts, followed by nonvolatile lockout if detection does not take place. Pump will continue to run only if the temperature is greater than 75 oC.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Ideal models that show the Lock-out fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal Lock-out fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026