BoilerFaultCodesWorcester Bosch 6.A Fault Code
Also written as 6A — same fault.
The Worcester Bosch 6.A fault code means: your boiler has failed to ignite properly, meaning it cannot create a flame to provide heating or hot water.. It appears on 2 Worcester Bosch models in our database.
Technical description: Last fault
What causes the Worcester Bosch 6.A fault?
This fault occurs when the boiler attempts to light several times but fails to detect a stable flame. The most common reasons include a lack of gas reaching the burner, contaminated ignition electrodes that can no longer create a spark, or a faulty gas valve preventing the fuel from flowing correctly.
This fault is more frequent during extreme cold snaps, as the internal components work harder and any moisture in the external gas meter or pipework can freeze, restricting the gas supply.
DIY fix possible
Check if other gas appliances, like a hob, are working to ensure gas supply is active.Inspect the condensate pipe outside for signs of freezing if the weather is very cold.Press the 'Reset' button on the boiler control panel for five seconds.
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 6.A fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 6.A 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