Furnace displays E11, may relate to domestic hot water (if combi-style furnace/boiler) or sensor issues.

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

Faulty DHW NTC sensor, Sticking DHW flow switch or turbine, Wiring fault between sensor and PCB, Limescale on DHW sensor pocket

Safety: Isolate power and water supply before removing any DHW components. Hot water can cause scalding.

User checks:

Run a hot tap and observe if the furnace attempts to fire before E11 appears. Note any irregularities for the technician.

Technician checks:

Test the DHW NTC sensor resistance and compare with Ravenheat data.
Inspect the DHW flow switch or turbine for debris or limescale; clean or replace as needed.
Check wiring continuity from the sensor/flow switch to the PCB.
Descale the DHW heat exchanger and sensor pocket if heavily scaled.

Hard 4/5

DHW NTC Sensor

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