HVACopedia

Lennox · Air handler

E346 Heat pump jumper not removed

High severity

What the control is telling you

The heat pump configuration link (O to R) on the air handler control was not cut. S30/S40 thermostat alert code 346 (shown as E346 on the unit control display).

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

Likely causes

  • Link not cut when a non-communicating heat pump is used with a communicating air handler

Test and repair steps

  1. Cut the O to R configuration link on the air handler control.
  2. Only applies to a non-communicating heat pump with a Lennox communicating indoor unit.
  3. Clears automatically once fixed.

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.26. 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.