Worcester Bosch Domestic Hot Water (DHW) NTC Sensor Fault

Boiler shows E6 and may cycle on and off rapidly, with incorrect temperature readings.

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.

Possible Causes

Failed DHW NTC sensor, Loose or corroded sensor connection, Scale build-up in DHW heat exchanger affecting sensor, PCB sensor input fault

Safety first: Turn off power and water supply before removing any DHW components.

Reset and test: Reset the boiler and run a hot tap. If E6 reappears, the DHW sensor circuit is likely faulty.
Check wiring: Inspect the DHW NTC sensor wiring at the plate heat exchanger for damage or loose plugs.
Engineer tasks: A technician should test the DHW NTC resistance, descale or replace the plate heat exchanger if heavily scaled, and replace the sensor or PCB as needed.

Medium 3/5

DHW NTC Temperature Sensor

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