A10
Ferroli DHW Temperature Sensor (NTC) Fault

Boiler shows A10 and stops; often related to domestic hot water (DHW) temperature sensing issues on combi models.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Failed DHW NTC sensor, Scale build-up around DHW sensor pocket, Loose sensor connection, PCB sensor input fault

How to Fix / Troubleshooting

Safety first: Isolate power and water before removing covers or sensors.

  • Check DHW operation: Run a hot tap and observe if the boiler attempts to fire before A10 appears. Intermittent firing suggests sensor issues.
  • Engineer checks:
    • Measure DHW NTC resistance and compare to spec.
    • Inspect the sensor pocket for scale; descale or replace as needed.
    • Replace the DHW NTC sensor if readings are unstable.
    • Check wiring and PCB for faults if sensor tests good.
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Repair Difficulty

Hard 4/5

Required Part

DHW NTC Temperature Sensor
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