Lennox communicating system shows E353 discharge air temperature sensor error; system may shut down or run erratically.

Safety: Turn off power to the indoor unit at the breaker before opening the blower/coil compartment.

• 1. Locate discharge air sensor: This sensor is typically mounted in the supply plenum or just downstream of the evaporator coil on Lennox communicating systems.
• 2. Inspect sensor and wiring: Ensure the sensor is firmly mounted in the airstream and its wires are intact. Look for insulation rubbed off where the wire passes through sheet metal.
• 3. Reseat connector: At the indoor control board, unplug and replug the sensor connector to clean contacts. Ensure it is fully seated.
• 4. Replace sensor if needed: If the sensor is cracked, corroded, or readings are clearly wrong, replace it with the correct Lennox discharge air temperature sensor.

Warning: Do not bypass temperature sensors; they protect the system from freeze-up and overheating.