BoilerFaultCodesWorcester Bosch Flue overheat Fault Code
Also written as FLUEOVERHEAT — same fault.
The Worcester Bosch Flue overheat fault code means: your boiler has shut down because it detected that the exhaust gases leaving the system have reached a dangerously high temperature.. It appears on 1 Worcester Bosch model in our database.
Technical description: Fault indication / Lockout reset button
What causes the Worcester Bosch Flue overheat fault?
This fault occurs when the internal sensors detect that the exhaust gases are getting far too hot, which can damage the boiler's internal components. The most common reason is a build-up of debris or limescale inside the main heat exchanger, which prevents heat from being transferred to your water and instead sends it out through the flue. It can also be caused by a physical blockage in the flue pipe or a failure of the safety thermostat itself.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Worcester Bosch models that show the Flue overheat fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch Flue overheat 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