Ariston (B) LED turning on Fault Code
Also written as BLEDTURNINGON — same fault.
The Ariston (B) LED turning on fault code means: your boiler has tried to ignite to provide heat but failed to detect a flame, causing the system to shut down for safety.. It appears on 3 Ariston models in our database.
Technical description: Shutdown due to lighting failure
DIY fix possible
Check that your gas emergency control valve is in the 'on' positionCheck if other gas appliances in your home, such as a hob, are working correctlyPress the 'R' or Reset button on the control panel to attempt a restart
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Gas Safe Register →Ariston models that show the (B) LED turning on fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston (B) LED turning on fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026