305 High
Your boiler's electronic control board has encountered an internal software error and can no longer process instructions correctly.
Technical description: All Boilers
Typical repair cost: £280-450 (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 305 — no call-out fees, no surprises.
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Parts commonly replaced
- Main Printed Circuit Board (PCB)
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