Thermostat display shows E1 and will not control heating or cooling

Safety first: Turn off power to the HVAC system at the breaker panel before removing the thermostat from the wall. Do not work on live low-voltage wiring.

• Step 1 – Power cycle: Turn off the furnace/air handler breaker for 2 minutes, then restore power. If E1 clears and does not return, it may have been a transient fault.
• Step 2 – Inspect thermostat placement: Confirm the thermostat is not exposed to direct sunlight or drafts that could cause extreme readings. This will not usually cause E1, but rule it out.
• Step 3 – Remove thermostat from sub-base: Gently pull the Amana smart thermostat straight off its wall plate. Inspect the back of the thermostat for any obvious damage or corrosion near the temperature sensor area (usually a small vented section).
• Step 4 – Check sensor connector: If accessible, gently press any small sensor connectors or ribbon cables into place on the thermostat’s circuit board. Look for broken or bent pins.
• Step 5 – Test continuity (advanced): With the thermostat removed and power off, use a multimeter to check continuity across the internal sensor terminals if they are exposed. An open reading indicates a failed sensor.
• Step 6 – Replace thermostat: If the sensor is open or the error persists after reseating connections, the internal sensor is not serviceable separately on most Amana smart thermostats. Replace the thermostat assembly with a compatible Amana smart thermostat model.

When to call a professional: If you are not comfortable removing the thermostat or using a multimeter, contact an HVAC technician or qualified electrician to diagnose and replace the thermostat.