BoilerFaultCodesTechnical description
HEATING THERMISTOR ON FLOW PIPE: CIRCUITS OPEN OR SHORT CIRCUIT. CHECK RESISTANCE OF THE THERMISTOR. (12500 ohms AT 20°C. 1750 ohms AT 70°C).
What causes this fault?
This fault occurs when the internal sensor responsible for measuring the water temperature as it leaves the boiler fails or loses its connection to the main control board. The most common reason is that the sensor's internal electrical components have degraded over time or a wire has become loose, preventing the boiler from knowing if it is overheating. As a safety precaution, the system stops firing because it can no longer accurately regulate the heat level.
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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