E16 displayed, often associated with overtemperature in condensing section or return line.

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

Blocked secondary heat exchanger, Restricted water flow, Faulty return NTC sensor, Air in system (on models with small circuit)

Safety: Turn off power and allow the unit to cool.

Check water flow: Ensure all isolation valves are fully open and inlet filters are clean.
Descale secondary heat exchanger: Isolate the heater and circulate descaling solution through the plate heat exchanger to remove limescale and sludge.
Bleed air (if applicable): On models with a small internal circuit, bleed any air from automatic air vents or manual bleed points.
Test return NTC: Measure resistance and replace if faulty.

Hard 4/5

Plate Heat Exchanger

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