BoilerFaultCodesWorcester Bosch 5.2 Fault Code
Also written as 52 — same fault.
The Worcester Bosch 5.2 fault code means: your boiler has detected a problem with its electronic ignition system, meaning it cannot process the command to start the flame safely.. It appears on 5 Worcester Bosch models in our database.
Technical description: GFA status / error
What causes the Worcester Bosch 5.2 fault?
This fault occurs when the boiler's internal computer is unable to communicate with or control the ignition system that lights the gas. It is typically caused by a electronic component failure on the main circuit board or a loose wiring connection between the controller and the ignition hardware. This prevents the boiler from safely starting the combustion process, causing it to shut down for safety.
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 5.2 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 5.2 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