BoilerFaultCodesYour heat pump has stopped working because a sensor that measures the temperature of the water leaving the outdoor unit has failed or is disconnected.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Outdoor Unit, Flow Thermistor (Tw_Out) Error
What causes this fault?
This fault occurs when the heat pump's control system loses the signal from the sensor that monitors the temperature of the water exiting the outdoor unit. The most common reason is that the sensor has developed an internal electrical failure, or its connecting wires have become damaged or corroded due to exposure to the elements. Without this data, the system cannot safely regulate heat production and shuts down to prevent damage.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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