BoilerFaultCodesYour boiler has detected a problem and has stopped working to prevent damage, requiring a simple reset to see if it clears the error.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: A fault has occurred. Fault reset button (6) should be pressed. If the boiler does not reset, or the fault persists, a service engineer should be contacted.
What causes this fault?
This fault occurs when the boiler's internal computer detects an operational error that prevents it from firing safely, such as a failure to ignite or a signal loss from a key component. The most common reasons include a worn-out ignition lead that can no longer create a spark or a fault within the main control board that manages the boiler's cycles.
DIY fix possible
Locate the reset button (marked with a '6' or a 'reset' icon) on the front control panel.Press and hold the reset button for approximately five seconds.Wait for the blue light to stop flashing and stay solid; if it begins flashing again, a professional is required.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like Blue mains indicator light flashing — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch Greenstar 24i Junior is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.