BoilerFaultCodesTechnical description
Temperature sensors faulty (CH sensor or Flue sensor).
What causes this fault?
This fault occurs when the boiler's control board loses communication with its temperature sensors or receives a reading that is outside of the safe range. The most common reason is that the internal thermistor has chemically degraded over time, or the electrical wiring connecting the sensor has become loose or damaged due to heat exposure.
This fault is slightly more common in autumn and winter when the boiler is pushed to operate at higher temperatures for longer periods, placing more thermal stress on aging sensors.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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