711 High
Your boiler has lost its ability to accurately measure the temperature of the water coming back from your radiators, which may stop your heating from working efficiently or at all.
Technical description: Return sensor defective (zone 1)
Typical repair cost: £90-160 (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 711 — no call-out fees, no surprises.
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Parts commonly replaced
- Return temperature sensor (NTC)
- Wiring harness
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