BoilerFaultCodesTechnical description
Outdoor Sensor within Outdoor Unit (T4) Error
What causes this fault?
This fault occurs when the heat pump loses communication with the sensor that monitors the temperature of the air outside. The most common reason is that the sensor itself has developed an electrical fault or the wiring has become corroded or loose due to exposure to the elements. Without this data, the system cannot calculate how hard it needs to work to keep your home warm.
This issue is more frequent during autumn and winter when moisture and frost can accelerate corrosion in the sensor's electrical connections.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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