Smart thermostat or Vaillant internet module feels unusually hot to the touch during normal operation.

Safety: If the casing is very hot or smells of burning, switch off power immediately and do not continue using the device.

• 1. Check mounting location: Ensure the thermostat or gateway is not installed directly above the boiler, inside a cupboard without ventilation, or near other heat sources.
• 2. Provide airflow: Relocate the device or improve ventilation around it. Do not cover with objects or enclosures.
• 3. Verify power supply: Confirm the device is powered by the correct Vaillant‑approved PSU or boiler connection and not an over‑voltage source.
• 4. Inspect for damage: If there is discoloration, warping, or burning smell, discontinue use and replace the device.
• 5. Professional check: Have a Vaillant technician inspect the system if overheating persists after relocation.