BoilerFaultCodesYour heat pump has stopped because a sensor that measures the temperature of the water leaving the outdoor unit is giving an incorrect reading.
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 internal computer receives an impossible or missing temperature reading from the water outlet pipe. The most common reason is that the sensor has physically failed due to wear and tear, or the electrical connection between the sensor and the main control board has become loose or damaged.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like HA — 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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