BoilerFaultCodesYour boiler has detected a problem with the sensor or switch that monitors water movement, preventing the system from heating up properly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pressure Sensor Error (UK) – Heating flow switch error (Ireland)
What causes this fault?
This fault occurs when the boiler detects a mismatch between the internal pump running and the actual movement of water through the system. The most common reason is a faulty pressure sensor or flow switch that is sending incorrect data to the control board, but it can also be caused by a blockage or trapped air preventing water from circulating freely.
This issue is often seen in autumn when the heating is turned on for the first time after summer, as internal parts can sometimes seize or stick during long periods of inactivity.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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