BoilerFaultCodesWorcester Bosch E9224 Fault Code
The Worcester Bosch E9224 fault code means: your boiler has shut down because a safety sensor has detected that the system is overheating or the sensor itself has a loose connection.. It appears on 3 Worcester Bosch models in our database.
Technical description: The contacts of the safety temperature sensor have been interrupted
What causes the Worcester Bosch E9224 fault?
This fault occurs when the boiler's internal safety switch detects that the heat exchanger has reached an unsafe temperature, causing the system to shut down to prevent damage. The most common reason is a lack of water flow through the unit, often caused by a failing pump, a blockage in the pipework, or air trapped within the heat exchanger. It can also be triggered if the wiring connecting the sensor to the main control board becomes loose or damaged.
This fault is more common when the heating is first turned on after autumn, as pump blockages often occur after long periods of inactivity during the summer.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Worcester Bosch models that show the E9224 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch E9224 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