BoilerFaultCodesYour boiler has lost communication with the main control board, meaning it cannot currently function or heat your home.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Clas HE evoClas he evo systemE-combi evoE-system evo
What causes this fault?
This fault occurs when the boiler's internal communication network fails, preventing different parts of the system from talking to each other. The most common reason is a malfunctioning main circuit board or loose internal wiring connections that have been damaged by vibrations or heat over time.
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.
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A boiler cover plan would cover faults like 204 — 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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