Display shows “rE” or “RE”; unit may not follow set temperature correctly.

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 remote temperature sensor, Miswired external control terminals, Broken communication cable to automation system

Safety first: Turn off power before working on low‑voltage wiring.

Check wiring: Inspect the low‑voltage terminal strip where remote or automation connections are made. Tighten loose screws and correct any miswiring per Heat Siphon diagrams.
Test remote sensor: If a remote water sensor is used, measure its resistance and compare to spec. Replace if defective.
Bypass remote: Temporarily disconnect the remote/automation wires and set the heater to local control. If rE clears and operation normalizes, the issue is in the external system.

Medium 3/5

Remote Temperature Sensor

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