BoilerFaultCodesWorcester Bosch EE4 Fault Code
The Worcester Bosch EE4 fault code means: your boiler is struggling to spark or stay lit, which means your heating and hot water have stopped working.. It appears on 1 Worcester Bosch model in our database.
Technical description: Ignition electrode
What causes the Worcester Bosch EE4 fault?
This fault occurs when the boiler's control system attempts to light the burner but fails to detect a successful flame. The most common reasons are worn-out spark electrodes that can no longer create a strong enough spark or a faulty ignition transformer that isn't providing the necessary electrical pulse to start the combustion process.
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 EE4 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch EE4 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