BoilerFaultCodesWorcester Bosch Off / Off Fault Code
Also written as OFFOFF — same fault.
The Worcester Bosch Off / Off fault code means: your boiler has completely lost power and its display screen is blank, meaning it cannot operate or heat your home.. It appears on 4 Worcester Bosch models in our database.
Technical description: No power at control board
What causes the Worcester Bosch Off / Off fault?
This fault occurs when the boiler's electrical circuit is broken, preventing power from reaching the internal computer. The most common reasons are a tripped fuse in your home's consumer unit, a blown fuse inside the boiler itself, or a total failure of the main printed circuit board. Essentially, the boiler is unable to 'wake up' because its electrical supply has been cut off.
This issue is slightly more frequent during winter due to power surges caused by stormy weather or increased electrical demand putting pressure on aging components.
DIY fix possible
Check if other appliances are working to rule out a general power cutCheck your home's main consumer unit (fuse box) to see if a circuit has trippedCheck the fused spur switch next to the boiler is turned on and the fuse inside hasn't blown
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Gas Safe Register →Worcester Bosch models that show the Off / Off fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch Off / Off 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