204 High
Your boiler has lost communication with the main control board, meaning it cannot currently function or heat your home.
Technical description: Clas HE evoClas he evo systemE-combi evoE-system evo
Typical repair cost: £180-350 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Protect yourself from future repair bills
A boiler cover plan would cover faults like 204 — no call-out fees, no surprises.
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Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Wiring Loom
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