BoilerFaultCodesTechnical description
Weather-compensated control units
What causes this fault?
This fault occurs when the boiler loses communication with the sensor mounted on your external wall. The most common reason is that moisture or corrosion has damaged the sensor's internal circuitry, or the electrical wiring connecting it to the boiler has become loose or broken. Because the boiler no longer knows how cold it is outside, it cannot automatically adjust its temperature to run at maximum efficiency.
This fault is more frequently reported during autumn and winter when heavy rain or freezing temperatures can expose existing damage or poor weather-sealing in the external sensor.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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