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Lennox · Air handler

E114 AC line frequency / distortion problem

High severity

What the control is telling you

Power to a component has a frequency or distortion problem; often transformer phasing, input power or overloading. Air handler control flags it when frequency is below 57 Hz or above 63 Hz for 10 seconds. S30/S40 thermostat alert code 114 (shown as E114 on the unit control display).

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

Likely causes

  • Generator with bad frequency
  • Transformer overload or phasing
  • Severe line distortion

Test and repair steps

  1. Check line voltage and frequency; if running on a generator, check its frequency.
  2. Correct voltage and frequency problems.
  3. Outputs are disabled (service soon); after 10 minutes it escalates. Damper module runs central mode only until fixed.
  4. With Lennox Smart Zoning set the damper module transformer jumper to system transformer, check wiring, replace the 40 VA furnace transformer with a 70 VA one, recommission.
  5. Note outdoor unitary controls do not display 114.
  6. Normal operation resumes five seconds after recovery.

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Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.16. 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.