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Lennox · Furnace

E370 Interlock switch open

High severity EL296UHVLennox SL280UHVLennox SL297NV

What the control is telling you

Control has lost 24 VAC on the interlock (DS) circuit for 2 minutes and stops all services.

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

Likely causes

  • Door/interlock switch open
  • Open in DS circuit

Test and repair steps

  1. Check that blower door and interlock switch are closed.
  2. Measure 24 VAC at the DS terminal.
  3. Repair wiring or replace the switch.
  4. Clears when 24 VAC is seen on DS for at least 10 seconds, or on power reset.

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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.

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.