BoilerFaultCodesYour boiler's computer may have encountered a temporary glitch or a more serious internal component failure.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Internal error.
What causes this fault?
This fault occurs when the boiler's main control board experiences a communication error or an internal electronic failure, preventing it from processing safety checks. It is often caused by a sudden power surge, moisture ingress, or simply the age of the electrical components leading to a system crash. Think of it like a computer freezing; the brain of the boiler can no longer send or receive the signals needed to operate safely.
DIY fix possible
Locate the reset button on the front control panel.Press and hold the reset button for 3 to 5 seconds.Wait for the boiler to restart and see if the code clears.
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 F0 — no call-out fees, no surprises.
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Worcester Bosch Greenstar 25 HE Combi 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.
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