F1 259 High
Your boiler's main internal computer or its configuration module has developed a communication failure, preventing the system from operating safely.
Technical description: Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
Typical repair cost: £250-£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 F1 259 — no call-out fees, no surprises.
*Affiliate links — we may earn a commission at no extra cost to you. Prices shown are starting prices.
Parts commonly replaced
- Heat Control Module (HCM)
- Printed Circuit Board (PCB)
*Affiliate links — we may earn a commission at no extra cost to you.