BoilerFaultCodesYour boiler is struggling to monitor the temperature outside, which is preventing it from adjusting your heating efficiently.
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: 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.
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 50:3 — no call-out fees, no surprises.
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