BoilerFaultCodesYour boiler has detected that a temperature sensor cable has disconnected or become faulty, preventing the system from monitoring water flow correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: HP flow sensor open / HP return sensor open
What causes this fault?
This fault occurs when the boiler's control board loses communication with the sensors that monitor the temperature of the water entering or leaving the unit. It is usually caused by a sensor internal failure, a loose connection, or damage to the wiring harness that prevents the electrical signal from reaching the main controller.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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