BoilerFaultCodesTechnical description
Flow sensor S1 defective
What causes this fault?
This fault occurs when the boiler's control board loses communication with the sensor responsible for measuring the heat of the water leaving the unit. The most common reason is that the internal components of the sensor have failed due to age or electrical wear, though it can also be caused by loose or damaged wiring connecting the sensor to the main board.
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.
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