301 High
Your boiler has detected a software or communication error on the main control board, which is preventing the system from operating correctly.
Technical description: All Boilers
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 301 — no call-out fees, no surprises.
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Parts commonly replaced
- Main PCB
- Wiring harness
*Affiliate links — we may earn a commission at no extra cost to you.