Thermostat displays E50 and reports an over-temperature condition; HVAC may shut down as a safety precaution.

Safety first: If the room is extremely hot, address the cause (e.g., failed AC, open windows) before working on the thermostat.

• Check installation location: Ensure the thermostat is not directly above a supply vent, near a fireplace, or in direct sunlight. If it is, consider relocating it to an interior wall away from heat sources.
• Verify actual room temperature: Use a separate thermometer to compare the room temperature to the thermostat reading. Large discrepancies suggest a sensor issue.
• Reboot the thermostat: Remove the display for 30 seconds, then reattach to reboot and see if E50 clears.
• Improve ventilation: Make sure the thermostat is not covered by furniture, curtains, or decorative covers that trap heat.
• Replace thermostat if sensor failed: If E50 persists and the room is at a normal temperature, the internal sensor may be damaged and the thermostat display should be replaced.