BoilerFaultCodesWorcester Bosch E80-450 Fault Code
Also written as E80450 — same fault.
The Worcester Bosch E80-450 fault code means: your boiler has detected a failure with the internal gas control valve, meaning it cannot safely ignite to provide heating or hot water.. It appears on 1 Worcester Bosch model in our database.
Technical description: Gas Valve – Natural Gas Dungs BM771 SL 040
What causes the Worcester Bosch E80-450 fault?
This fault occurs when the boiler's main control board loses electrical communication with the gas valve or detects that the valve is physically unable to open. The most common reason is an internal mechanical failure within the valve itself or a loose connection in the wiring harness that prevents the flow of gas required for ignition.
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 E80-450 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch E80-450 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