E270 Soft lockout - no flame after max retries

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.

Settings for these units

Recommended filter size by cabinet width · EL296UHV

Number in brackets is the quantity of filters.

Filters are field supplied and installed outside the furnace; inspect monthly.

Recommended filter size by cabinet width · Lennox SL280UHV

Number in brackets is filter quantity; filters are field supplied.

Never run the unit without a filter installed.

• Filter sizes by cabinet width · Lennox ML180UHE
• Filter sizes by cabinet width · Lennox SL297NV

Models that show this code

34 models in EL296UHV, Lennox SL280UHV, Lennox ML180UHE, Lennox SL297NV

Other codes on the same units

• E240 Low flame current (run mode)
• E241 Flame sensed out of sequence - flame present
• E250 Limit switch circuit open
• E252 Discharge air temperature too high
• E271 Soft lockout - retries exceeded, pressure switch opened
• E272 Soft lockout - recycles exceeded, pressure switch opened
• E273 Soft lockout - recycles exceeded, flame failure
• E274 Soft lockout - limit opened