BoilerFaultCodesWhat the manual says
Manufacturer manualCentral Heating flow thermistor fault.
What causes this fault?
This fault occurs when the boiler's internal computer stops receiving a reliable signal from the sensor that monitors the temperature of the water leaving the unit. The most common reason is that the sensor has physically failed due to age or internal wear, though damaged wiring or loose connections between the sensor and the main control board can also be responsible.
This fault is slightly more common in winter when the boiler is working harder and the sensor is subjected to more frequent and extreme temperature cycles.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like F6: no call-out fees, no surprise bills.
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