BoilerFaultCodesYour boiler's internal computer has encountered a major communication error and has stopped working to protect the system.
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 suffers a critical internal failure or loses the ability to talk to its sensors. It is usually caused by a physical malfunction within the electronic circuitry or loose connections in the internal wiring harness. Think of it as a computer crash where the system has to shut down completely because it can no longer verify that the boiler is operating safely.
DIY fix possible
Locate the reset button on the boiler control panelPress and hold the reset button for five secondsWait 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 ZB 7 27 HE 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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