4070 High
Your boiler has detected that the water temperature is too high and has shut down to prevent damage to its internal components.
Technical description: Fault flow sensor over temperature – flow sensor flow/return line probe differential alarm
Typical repair cost: £120-280 (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 4070 — no call-out fees, no surprises.
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Parts commonly replaced
- Flow Thermistor
- Return Thermistor
- Circulation Pump
- Main Heat Exchanger
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