BoilerFaultCodes 702 Medium Warning
Your boiler has detected a fault with a temperature sensor serving a secondary heating area, meaning that specific zone may not heat up correctly.
Book a service
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Send sensor defective (Zone 2)
What causes this fault?
This fault occurs when the control board loses communication with the sensor monitoring the water temperature for your second heating zone. This is usually caused by the internal sensor failing due to age or a loose electrical connection in the wiring harness between the sensor and the main board.
Typical repair cost £100-180 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like 702 — no call-out fees, no surprises.
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