F6 High
Your boiler has detected a problem with the sensor that monitors the temperature of the water heading to your radiators, causing the system to shut down for safety.
Technical description: Central heating flow thermistor fault
Typical repair cost: £100-£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 F6 — no call-out fees, no surprises.
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Parts commonly replaced
- Central heating flow thermistor (NTC sensor)
- Connecting wiring harness
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