BoilerFaultCodesThe boiler's internal sensor that monitors water temperature or flow has failed, meaning the system cannot safely regulate heat.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow sensor damaged
What causes this fault?
This fault occurs when the boiler's internal thermometer, which monitors the temperature of the water leaving the unit, stops sending a reliable signal to the main control board. The most common reason is that the sensor has physically failed due to age or heat stress, though it can also be caused by loose or corroded electrical connections between the sensor and the boiler's computer.
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 03E — no call-out fees, no surprises.
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