BoilerFaultCodesYour boiler's internal computer has encountered a critical error and can no longer communicate with the heating controls, causing the system to stop working.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Internal fault: FW 100 can no longer control the heating system!
What causes this fault?
This fault occurs when the boiler's main control board suffers a hardware failure and loses its ability to send or receive messages from the heating system. The most common reason is an electrical short or component degradation on the printed circuit board, which effectively leaves the boiler without its digital 'brain'.
DIY fix possible
Locate the reset button on the front control panelPress and hold the reset button for five seconds until the display changesWait for the boiler to restart; if the code returns immediately, a professional repair 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 Fault 02 / 255 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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