BoilerFaultCodesTechnical description
External sensor fault (if fitted)
What causes this fault?
This fault occurs when the boiler's control board loses its connection to the sensor located on the outside of your property. The most common reason is that moisture or corrosion has damaged the sensor's internal circuitry, or the thin wires connecting it to your boiler have become broken or loose.
This fault is more common during autumn and winter, as heavy rain or freezing temperatures can cause water ingress or physical damage to the external sensor unit.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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