Thermostat shows E13, and backlight or display segments are missing.

Safety first: Turn off the power at the breaker before removing the thermostat from the wall.

Steps to troubleshoot E13 (display fault):

• 1. Power cycle:
  • Turn off the power for 2–3 minutes and restore.
  • Check if the display returns to normal.
• 2. Inspect for physical damage:
  • Remove the thermostat and examine the front for cracks or impact marks.
  • If the glass or plastic is cracked, the display is likely physically damaged.
• 3. Check internal connections (if accessible without breaking warranty seals):
  • Some models have a ribbon cable between the PCB and the display.
  • If accessible, gently press the connectors to ensure they are seated.
• 4. Use the app for control:
  • If only the display is faulty but the thermostat still responds via the Fibaro app, you can temporarily control heating from the app.
• 5. Replace the thermostat front module:
  • In most cases, the display is integrated with the front housing and must be replaced as a unit.

When to call a professional: If the thermostat is under warranty, contact Fibaro support or your installer for a replacement rather than opening the device further.