BoilerFaultCodesTechnical description
Fault: NTCs fitted incorrectly Flow/return temperature sensors returning incorrect/implausible values. Check: Flow/return temperature sensor (correct thermal connection).
What causes this fault?
This fault occurs when the boiler's control board detects that the temperature sensors are not sending consistent or logical readings. The most common reason is that the sensors have vibrated loose from the internal pipes or were accidentally clipped onto the wrong ones during a recent repair. Because the boiler cannot accurately track how hot the water is, it shuts down for safety.
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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