705 High
Your boiler has lost communication with the internal temperature sensor for the heating system, meaning it cannot monitor how hot the water is getting.
Technical description: E-Combi EvoE-System EVOClas HE evo combiClas he evo system
Typical repair cost: £90-180 (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 705 — no call-out fees, no surprises.
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Parts commonly replaced
- NTC Temperature Sensor
- Wiring Harness
- Main Control Board
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