BoilerFaultCodesYour boiler has lost power or experienced an electrical error while it was already trying to show a different fault code.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: The power has been interrupted during a lockout
What causes this fault?
This fault occurs when the boiler loses electrical power at the exact moment it was trying to record or display a different technical error. It is usually caused by a loose connection in the internal wiring or a failing main circuit board that can no longer process electrical signals correctly. Essentially, the boiler's internal computer has crashed while trying to report a problem, leaving it in a confused state.
DIY fix possible
Locate the reset button on the front control panelPress and hold the reset button for five secondsWait for the boiler to restart and see if a different fault code appears
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 FD231 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch CDi Classic 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.