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Lennox · Air handler

E310 Discharge air temperature sensor problem

Medium severity

What the control is telling you

Problem with the discharge air temperature sensor (DATS). S30/S40 thermostat alert code 310 (shown as E310 on the unit control display).

Applies to: Lennox communicating air handlers and EIM-equipped indoor units in S30/S40 smart thermostat systems

Likely causes

  • Open or shorted sensor or wiring
  • Short/open in thermostat communication connections

Test and repair steps

  1. Check for shorts or opens in the communicating thermostat connections to all components.
  2. Compare DATS resistance with the temperature/resistance chart in the unit instructions.
  3. Replace the sensor if necessary.
  4. Note DATS on a damper control module or EIM does not generate this alert.
  5. Clears 30 seconds after recovery or after restart.

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Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.25. Summarized in our own words; check the original manual for your model.

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For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.