BoilerFaultCodesTechnical description
Central heating thermistor sensor fault
What causes this fault?
This fault occurs when the sensor responsible for measuring the temperature of the water in your heating system becomes faulty or loses its connection to the main control board. If the boiler cannot accurately track how hot the water is, it will shut down as a safety precaution to prevents the system from overheating. The most common reason is that the internal component has simply worn out over time or the wiring connecting it has become loose or damaged.
This fault is more common in autumn when the heating is turned on for the first time after summer, as the sudden change in temperature and system pressure can cause an aging sensor to fail.
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.