BoilerFaultCodesWorcester Bosch Volatile lockout Fault Code
Also written as VOLATILELOCKOUT — same fault.
The Worcester Bosch Volatile lockout fault code means: your boiler has stopped running and entered a safety shutdown mode, which is indicated by the reset button flashing.. It appears on 1 Worcester Bosch model in our database.
Technical description: Fault indication / Lockout reset button
What causes the Worcester Bosch Volatile lockout fault?
This fault occurs when the boiler's control system detects a failure in the ignition process or a loss of flame signal during operation. The most common reasons are that the burner has failed to light correctly or the internal sensors can no longer verify that a flame is present for safety. This results in the boiler shutting down immediately to prevent unburnt gas from building up in the system.
DIY fix possible
Press and hold the flashing Reset button for five seconds.Wait for the blue light to stop flashing and stay on constant.Ensure your gas supply is active and your system pressure is between 1 and 1.5 bar.
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Gas Safe Register →Worcester Bosch models that show the Volatile lockout fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch Volatile lockout fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026