BoilerFaultCodesWorcester Bosch Over temperature Fault Code
Also written as OVERTEMPERATURE — same fault.
The Worcester Bosch Over temperature fault code means: your boiler has reached an unsafe temperature and has automatically shut down to prevent damage and ensure your safety.. It appears on 1 Worcester Bosch model in our database.
Technical description: Primary temperature 94°C (until 84°C) - shut down burner. Water over 89°C - shut-down. Gas valve OFF.
What causes the Worcester Bosch Over temperature fault?
This fault occurs when water inside the boiler cannot flow away quickly enough, causing it to rapidly overheat and trigger a safety shutdown. The most common reasons are a seized internal pump that isn't pushing water around the system, or a blockage such as trapped air or a build-up of sludge. In some cases, a faulty sensor may simply be misreading the temperature even if the water itself is fine.
This issue often appears when the heating is first turned on after summer, as the pump can seize up during long periods of inactivity.
DIY fix possible
Check if any radiator valves have been turned off and open them fullyEnsure your system pressure is between 1 and 1.5 bar on the pressure gaugeOnce the boiler has cooled down, press the reset button
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Gas Safe Register →Worcester Bosch models that show the Over temperature fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch Over temperature 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