E10
Sime Return Temperature Sensor (NTC) Fault

Boiler displays E10, no heating or hot water, may be associated with return temperature sensor

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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 return NTC sensor, Wiring damage, Poor sensor contact with return pipe, PCB sensor input fault

How to Fix / Troubleshooting

Safety first: Isolate power before removing covers or disconnecting sensors.

  • Inspect return NTC: Locate the return NTC on the return pipe. Check that it is firmly clipped and that the cable is intact.
  • Reseat connector: Disconnect and reconnect the sensor plug to clear any oxidation on the contacts.
  • Measure resistance (engineer task): Compare the sensor resistance to the Sime chart. Replace if readings are incorrect or intermittent.
  • Check PCB connection (engineer task): Ensure the harness is correctly connected to the main PCB and that there is no water ingress on the board.
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Repair Difficulty

Medium 3/5

Required Part

Return NTC Temperature Sensor
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