HVACopedia

Lennox · Furnace

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 gas furnaces (e.g. SL280UHV/SL280UHNV, EL296UHV) 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.

Settings for these units

Save it for the next call

Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.

Open the app

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.