BoilerFaultCodesYour boiler has detected a problem with its internal temperature sensor and has shut down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Casting Thermistor Fault
What causes this fault?
This fault occurs when the boiler's internal temperature sensor, known as the casting thermistor, provides an incorrect or inconsistent reading to the main control board. The most common reason is that the sensor has physically failed or degraded over time, though it can also be caused by loose or damaged wiring connecting the sensor to the boiler's computer.
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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