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Lennox · Heat pump

E414 High discharge line temperature

Medium severity

What the control is telling you

Discharge line temperature is above the 279 F limit. S30/S40 thermostat alert code 414 (shown as E414 on the unit control display).

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

Likely causes

  • Dirty coil or blocked airflow
  • Low charge / high superheat
  • Abnormal operating pressures

Test and repair steps

  1. Clean the coil and clear airflow in and out of the condenser.
  2. Check pressures against the unit charging charts.
  3. Clears when discharge temperature drops below 225 F.

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Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.30. 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.