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Lennox · Air handler

532 Zoning pressure switch opened (high pressure)

Low severity

What the control is telling you

Zoning pressure switch opened: compressor pressure above limit, compressor off; zoning restores when the switch closes (dealer information). S30/S40 thermostat alert code 532.

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

Likely causes

  • High refrigerant pressure during zoning (low airflow)
  • AC system without the switch

Test and repair steps

  1. Check airflow and bypass in zoned operation.
  2. On some AC systems, the fix is a jumper across the damper control module's pressure switch terminals.
  3. Clears when pressure is within limits.

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Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.44. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

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.