Lennox EL296UHV Error Code E 272: Soft Lockout - Pressure Switch Recycle Failed
What Does Code E 272 Mean?
Error code E 272 on the Lennox EL296UHV is a pressure-switch recycle soft lockout. A recycle happens when the furnace has already lit and is running, then a safety condition forces it to shut down and start the sequence over. In this case each recycle was caused by a pressure switch opening, and after exceeding the maximum number of recycles the SureLight integrated control declared a soft lockout. Like the model's other soft lockouts, it recovers on its own once a heat call finishes successfully instead of requiring a manual reset.
The distinction from E 271 is important. E 271 (pressure-switch retry failed) means the furnace could not even get through its ignition retries because draft was never proven. E 272 means the burners did light and prove flame, but a pressure switch then opened mid-run enough times to exhaust the recycle count. Because the EL296UHV is a two-stage furnace with a low and a high pressure switch, a recycle can come from either firing rate — for example, draft that holds on low fire but falls short when the furnace steps up to high fire.
This "runs, then drops out" pattern typically comes from causes that appear or worsen while the furnace is operating: a vent that restricts as condensate collects, moisture accumulating in a pressure-switch hose, or an inducer that slows as it warms. It is closely related to E 227, which flags a pressure switch opening during operation. A technician needs to check both pressure switches, the vent system, and the inducer to find why draft is not holding under load.
What You'll Notice
- No heat, with the seven-segment LED showing E 272
- The furnace lights and runs briefly, then shuts down and tries to restart
- This start-then-stop cycle repeats several times before the furnace gives up
- You may hear the inducer and burners cut out partway through a heating cycle
- The problem can be worse once the furnace has been running for a few minutes
How This Is Diagnosed
Because the furnace proves flame before dropping out, a technician looks for a draft condition that fails under running load rather than at startup. They inspect the vent and intake for a restriction that develops as the system heats, check the pressure-switch hoses for trapped condensate or cracks, and confirm the inducer holds its speed while hot.
With the furnace running they measure the pressure each switch sees at both the low and high firing rates and compare it to the switch closing points, since a recycle can occur when the furnace steps up to high fire and draft falls short. If draft is adequate but a switch still opens, the switch, its tubing, or its wiring is the next suspect.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The furnace lights and then shuts down partway through the cycle, repeatedly
- E 272 appears across multiple heating cycles
- The vent termination looks clear but the drop-outs continue
- You also see E 227 (pressure switch opening during operation) in the history
- The drop-outs seem to happen when the furnace ramps up to full heat
Frequently Asked Questions
How is E 272 different from E 271?
E 271 means the furnace never got through its ignition retries because draft was not proven. E 272 means the burners did light and run, but a pressure switch then opened during operation enough times to exhaust the recycle limit.
Why does it run for a bit before failing?
Many causes of E 272 only show up under load — condensate collecting in the vent or hose, or an inducer slowing as it warms. On a two-stage furnace, draft can also fall short only when the unit steps up to high fire.
Will it reset itself?
Yes, the soft lockout clears after a heat call completes successfully. But the furnace will keep recycling and relocking until the vent, hose, switch, or inducer issue is corrected.
✓ Verified against manufacturer service manual — March 2026