BoilerFaultCodesWorcester Bosch EC256 Fault Code
The Worcester Bosch EC256 fault code means: your boiler's computer system has detected an internal electronic fault, preventing the heating and hot water from starting up.. It appears on 1 Worcester Bosch model in our database.
Technical description: The burner control unit has an error
What causes the Worcester Bosch EC256 fault?
This fault occurs when the boiler's internal computer can no longer communicate correctly with the parts that manage the flame. The most common reason is an electronic failure within the control board or a loose connection in the internal wiring. This prevents the boiler from safely starting the ignition process, so it shuts down to protect the system.
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 EC256 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch EC256 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