E11
Termet DHW Flow Switch / Turbine Fault

Boiler intermittently locks out with E11, especially during hot water use, sometimes with fluctuating temperatures.

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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

Sticking DHW flow turbine in Termet hydraulic block, Limescale or debris in DHW inlet filter, Faulty DHW flow switch or Hall sensor, Wiring issue between DHW flow sensor and PCB

How to Fix / Troubleshooting

Safety first: Isolate power and close the cold water inlet before removing DHW components.

User checks:

  • Clean any external inlet filters or strainers on the cold water supply to the boiler if accessible.
  • Open a hot water tap fully and observe if the boiler recognises demand (flame symbol). If not, E11 likely relates to flow detection.
  • Reset the boiler once. If the problem persists, call a technician.

Technician checks:

  • Remove and clean the DHW flow turbine / flow sensor in the hydraulic block, removing limescale and debris.
  • Check the DHW inlet filter and flush the plate heat exchanger if heavily scaled.
  • Test the sensor output with a multimeter while water is flowing.
  • Replace the DHW flow sensor assembly if defective.

After repair, verify stable DHW operation at various flow rates.

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Repair Difficulty

Medium 3/5

Required Part

DHW Flow Sensor / Turbine
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