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Lennox · Furnace

E347 No 24 V on Y1 output

Critical severity EL296UHVLennox SL280UHVLennox SL297NV

What the control is telling you

With a non-communicating outdoor unit, Y1 relay/stage 1 failed. Operation stopped; critical alert.

Applies to: EL296UHV(X) series furnaces (integrated control 103130-XX and 107045-XX)

Likely causes

  • Y1 pilot relay contacts did not close
  • Relay coil not energized

Test and repair steps

  1. Measure 24 VAC at the Y1 output during a cooling call.
  2. Check wiring to the outdoor unit.
  3. Replace the integrated control if no output.
  4. Clears after reset and Y1 input is sensed.

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Source: Lennox EL296UHV(X) Unit Information / Service Literature, Table 5 Ignition Control 103130-XX Diagnostic Codes, p.37; Ignition Control 107045-XX Diagnostic Codes table, p.44. 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.