Thermostat shows E15 and reports an internal temperature overheat condition; device may shut down temporarily.

Safety first: Turn off HVAC power at the breaker before relocating or removing the thermostat.

• Step 1 – Check installation location: Ensure the thermostat is not directly above a supply register, radiator, or other heat source, and not in direct sunlight for extended periods.
• Step 2 – Improve airflow: Make sure the thermostat's side and bottom vents are not blocked by paint, wallpaper, or obstructions. Gently clean dust from vents with a soft brush.
• Step 3 – Seal wall cavity: If hot air is leaking from the wall cavity behind the thermostat, seal the opening with foam or putty to prevent heat from rising behind the unit.
• Step 4 – Monitor temperature: After making changes, allow the thermostat to cool and monitor if E15 recurs during normal operation.
• Step 5 – Replace thermostat if internal fault: If E15 appears even in a cool, shaded location with good airflow, the internal regulator or sensor may be overheating. Replace the thermostat head unit.