B7 257 High
Your boiler's internal computer or its identification chip has developed a communication failure, preventing the system from operating.
Technical description: The burner control unit or the KIM (boiler identification module) is faulty
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 B7 257 — no call-out fees, no surprises.
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Parts commonly replaced
- Burner Control Unit (PCB)
- KIM (Boiler Identification Module)
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