BoilerFaultCodesYour boiler has lost connection to its outdoor temperature sensor, which helps it run efficiently based on the weather outside.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Outdoor sensor not detected.
What causes this fault?
This fault occurs when the boiler's control board can no longer communicate with the sensor located on the outside of your home. The most common reason is a break or loose connection in the wiring that runs between the boiler and the sensor, though the sensor itself can occasionally fail due to weather exposure.
This fault is more frequently noticed during the transition into autumn and winter, as this is when the boiler relies most heavily on the outdoor sensor to calculate how much heat the home needs.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like CC — no call-out fees, no surprises.
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