Thermostat shows E3 and indoor temperature reading is obviously wrong (e.g., displays 120°F in a normal room).

Safety first: Turn off power to the HVAC system at the breaker before removing the thermostat from its base.

Steps to troubleshoot:

• 1. Reboot the thermostat: Remove the thermostat from the wall plate for 30 seconds, then reattach. If it has a reset option in the menu, perform a soft reset. Check if E3 clears.
• 2. Check mounting location: Ensure the thermostat is not installed above supply registers, near exterior doors, in direct sunlight, or on an uninsulated exterior wall. Excessive heat or cold can cause sensor errors. Relocate the thermostat if needed.
• 3. Inspect the backplate connection: Verify the thermostat is fully seated on the Bryant wall plate and that the pin connectors are clean and straight. Gently clean contacts with a dry cloth.
• 4. Compare with a reference thermometer: Place an accurate digital thermometer near the thermostat and compare readings. If the thermostat is far off and E3 persists, the internal sensor is likely defective.
• 5. Professional replacement: Internal temperature sensors are not field-repairable. Replace the Bryant smart thermostat if the sensor is faulty and under warranty, or have a technician confirm and replace.