BoilerFaultCodesWorcester Bosch FA364 Fault Code
The Worcester Bosch FA364 fault code means: your boiler has detected a potential internal gas leak during its safety checks and has shut down to keep your home safe.. It appears on 1 Worcester Bosch model in our database.
Technical description: Gas valve EV2 leak test failed – gas valve leak
What causes the Worcester Bosch FA364 fault?
This fault occurs when the boiler's internal safety checks detect that gas is passing through the system when it should be shut off. The most common reason is a mechanical failure in the gas valve which prevents it from sealing properly, or a communication error from the main control board that incorrectly monitors the gas flow.
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 FA364 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch FA364 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