BoilerFaultCodesYour boiler’s internal computer and main controls have lost their connection, preventing the system from starting up.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Break in communication
What causes this fault?
This fault occurs when the 'brain' of your boiler can no longer talk to the control panel or the internal sensors. It is usually caused by moisture affecting the electrical circuits, a loose connection in the internal wiring, or a critical failure of the main printed circuit board itself.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 A8 — 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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