Armstrong Air communicating thermostat displays E1; furnace may shut down or not respond.

Steps to check:

• Verify sensor location: Ensure the thermostat or remote sensor is not exposed to direct sunlight, drafts, or heat sources that could cause erratic readings.
• Inspect sensor wiring: If a remote indoor sensor is used, check its wiring for loose connections or damage.
• Reset thermostat: Power down the system and remove the thermostat from its base for 30 seconds, then reinstall and restore power.
• Replace thermostat or sensor: If the E1 code persists and wiring is intact, replace the thermostat or remote sensor with an Armstrong-compatible part.