704 High
Your boiler has stopped working because of an internal communication failure between the main control board and the display panel.
Technical description: E-Combi EvoE-System EVOClas HE evo CombiClas HE evo System
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 704 — no call-out fees, no surprises.
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Parts commonly replaced
- Main PCB
- Display Interface
- Wiring Loom
*Affiliate links — we may earn a commission at no extra cost to you.