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Lennox · Air conditioner

70501 Smart room sensor internal data fault

Medium severity

What the control is telling you

Room sensor cannot collect samples or readings out of range, or occupancy sensor voltage below 0.2 V or above 2.5 V. S30/S40 thermostat alert code 70501.

Applies to: Lennox communicating air conditioners incl. variable-capacity inverter units in S30/S40 smart thermostat systems

Likely causes

  • Sensor fault

Test and repair steps

  1. Power cycle the Smart Room Sensor.
  2. Wait 10 minutes for self-clearing (temperature/RH); occupancy self-clears in 45 minutes (3 x 15 minute intervals).

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Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.49. 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.