BoilerFaultCodesTechnical description
Flow Thermistor
What causes this fault?
This fault occurs when the internal sensor responsible for measuring the water temperature as it leaves the boiler fails or provides an unrealistic reading. The most common reason is that the sensor has physically degraded over time or a loose electrical connection has developed, preventing the control board from safely monitoring the heat levels.
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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