E3
Saunier Duval User Interface Hardware Error

Thermostat shows E3 and touch screen or buttons do not respond correctly

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Safety Warning

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.

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Possible Causes

Faulty capacitive touch panel, Damaged ribbon cable between display and PCB, Liquid ingress on front panel, Firmware glitch affecting UI driver

How to Fix / Troubleshooting

Safety: Turn off power to the thermostat before removing it from the wall.

  • Clean surface: Wipe the screen with a dry, soft cloth. Do not use liquids or sprays directly on the thermostat.
  • Power cycle: Remove the thermostat from its base or disconnect power for 1–2 minutes, then restore power.
  • Check for damage: Inspect the front panel for cracks or signs of impact. If the glass is cracked or there is evidence of water ingress, the unit must be replaced.

If E3 persists and the UI remains unresponsive, replacement of the thermostat is required; the touch panel is not user-serviceable.

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Repair Difficulty

Medium 3/5

Required Part

Saunier Duval Smart Thermostat Display / Touch Panel
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