BoilerFaultCodesYour boiler has detected a fault with the sensor that monitors the temperature of the water leaving the unit to heat your radiators.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: CH flow thermistor error
What causes this fault?
This fault occurs when the boiler's control board loses communication with the sensor that monitors the temperature of the water heading to your radiators. The most common reason is that the internal components of the sensor have failed due to age, or the electrical connection has become loose or corroded. Because the boiler no longer knows how hot the water is, it shuts down as a safety precaution to prevent overheating.
This fault is more common in autumn and winter when the heating is first switched back on and the sensor is subjected to rapid changes in temperature.
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 E05 — no call-out fees, no surprises.
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