E25 displayed, water temperature fluctuates or is limited.

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 modulating gas valve, Sticking water flow modulator, Incorrect NTC readings, PCB control error

Safety: Isolate gas and power before internal work.

Verify NTC sensors: Check DHW NTC resistance and mounting. Replace if readings are unstable.
Inspect water modulator (if fitted): Some Chaffoteaux models use a water pressure modulator or stepper motor. Check for limescale or mechanical sticking and clean/replace as needed.
Gas valve modulation: A qualified technician should verify that the gas valve modulates correctly with changing water flow.
PCB replacement: If all hardware is correct, the PCB may be mis-controlling temperature.

Professional Required 5/5

Gas Valve Assembly

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