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Lennox · Furnace

E270 Soft lockout - no flame after max retries

High severity EL296UHVLennox SL280UHVLennox ML180UHELennox SL297NV

What the control is telling you

Ignition retries exhausted without sensing flame.

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

Likely causes

  • No gas or low gas pressure
  • Ignitor not lighting burners
  • Flame sensor not sensing

Test and repair steps

  1. Warning: Do not try to light the burners by hand; smell for gas near the floor before working on the unit.
  2. Know the sequence inducer 15 s pre-purge, 20 s ignitor warm-up, then gas valve opens on low fire and flame must be sensed within 4 seconds; failed trials get a 15 s inter-purge, and after the 5th failed trial the control goes into Watchguard (auto-reset after 1 hour).
  3. Confirm gas is on at the meter, the manual shut-off valve and the gas valve switch; purge air from the line on a new start-up.
  4. Check gas pressures with a manometer supply natural gas 4.5-13.0 in. w.c. (LP 11.0-13.0); manifold natural 1.7 low fire / 3.5 high fire (LP 4.5 / 10.0) at 0-4500 ft.
  5. Watch a trial verify the ignitor glows and burners light. Check ignitor resistance at the control (terminals 1 and 5): 39-70 ohms, and 120 V +/-10% during warm-up.
  6. Check flame current in F mode (2.6 uA or more normal; drop-out at 1.1 uA); clean or replace the flame sensor.
  7. Check ground at the control AC volts between line neutral and the C terminal should not exceed 2 VAC at idle, 5 VAC with inducer/ignitor on, 10 VAC with blower on; a wide swing under load means a poor ground. Line hot to neutral should be 97-132 VAC.
  8. If burners are dirty, shut off power and gas, remove the burner box and vacuum the burner faces with a soft brush, then realign burners to the ports.
  9. Clears after a successful heat call; Watchguard also resets after 1 hour of continuous demand, or cycle the thermostat/power.

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Source: Lennox EL296UHV(X) Unit Information / Service Literature, Table 5 Ignition Control 103130-XX Diagnostic Codes, p.35; Ignition Control 107045-XX Diagnostic Codes table, p.42, Troubleshooting: Heating Sequence of Operation flowchart, p.110-112, Heating System Service Checks p.82-85, Maintenance p.88-89. 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.