328 High
Your boiler has detected an issue with the quality of the electricity supply coming into your home, meaning it cannot operate safely.
Technical description: Internal error with the mains voltage – frequency may be inconsistent
Typical repair cost: £250-550 (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 328 — no call-out fees, no surprises.
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Parts commonly replaced
- Printed Circuit Board (PCB)
- Mains Power Supply Filter
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