BoilerFaultCodesYour boiler has detected an issue with the sensor that measures the temperature of the water leaving the unit, which usually results in the system shutting down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow temperature sensor error – try resetting the boiler
What causes this fault?
This fault occurs when the boiler's internal computer stops receiving a reliable signal from the sensor that monitors the heat of the water leaving the unit. The most common reason is that the sensor has physically failed or developed a short circuit, but it can also be caused by loose or damaged wiring between the sensor and the main control board.
DIY fix possible
Locate the power button or reset switch on the boiler control panelPress and hold the reset button for five secondsWait for the boiler to restart and check if the error code clears
Find a Gas Safe engineer
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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 81-01 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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