Lennox EL296UHV Error Code E 271: Soft Lockout - Pressure Switch Retry Failed
What Does Code E 271 Mean?
Error code E 271 on the Lennox EL296UHV is a pressure-switch-retry soft lockout. Before the burners can light, the SureLight integrated control must see the pressure switch prove that the inducer is drawing proper draft. On this fault the control retried the maximum number of times, and on the last retry the pressure switch opened, meaning adequate draft was never confirmed. The control then dropped into a soft lockout, which recovers on its own once a heat call finishes successfully rather than needing a manual power reset.
As a two-stage furnace, the EL296UHV has both a low and a high pressure switch, one for each firing rate. E 271 tells you the retry sequence failed on a pressure-switch opening, so the draft the switch is supposed to confirm is either not being produced or not being sensed. The most common physical causes are a restricted vent or combustion-air intake and a weak or failing inducer.
E 271 is closely related to E 272, the pressure-switch recycle soft lockout: E 272 means the furnace repeatedly recycled after starting because a pressure switch opened during the run, while E 271 means it failed during the initial retry attempts before proving flame. It also sits alongside E 227 and E 223, which flag pressure-switch and draft-proving faults on the same control. When you see E 271, the draft-proving side of the system is what needs attention.
What You'll Notice
- No heat, with the seven-segment LED showing E 271
- The inducer runs but the burners never light, then the furnace shuts down
- You may notice ice, debris, or a nest at the vent or intake termination outside
- Repeated short attempts to start followed by the furnace going quiet
- The problem is often worse in wind, snow, or after a storm that can block the vent
How This Is Diagnosed
A technician starts at the draft-proving chain. They inspect the vent and combustion-air intake piping for blockage, sagging, standing water, or a restricted outdoor termination, since a plugged vent is the most common reason the pressure switch will not stay closed. They then confirm the combustion-air inducer is spinning up to speed and actually moving air.
With the inducer running they measure the actual pressure the switch sees, in inches of water column, and compare it to the low pressure switch's closing point. If draft is adequate but the switch still opens, the switch itself, its tubing, or its wiring is suspect; if draft is low, the focus stays on the inducer and vent restriction.
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:
- E 271 comes back every time the furnace tries to start
- The vent or intake termination outside looks blocked, iced over, or damaged
- The inducer sounds weak, noisy, or does not seem to spin up fully
- The code appears alongside E 272, E 227, or E 223
- The lockout began after high wind, heavy snow, or work on the venting
Frequently Asked Questions
What is the pressure switch actually checking?
It confirms the combustion-air inducer is pulling proper draft before gas is allowed to flow. If the switch does not prove that draft, the control blocks ignition, which is exactly what happened here.
Why would the vent be blocked?
Common causes include snow or ice over the outdoor termination, a bird or rodent nest, sagging pipe that traps condensate, or debris. The EL296UHV depends on a clear intake and exhaust to hold the pressure switch closed.
Does this code clear on its own?
Yes, it is a soft lockout that clears after a heat call completes successfully. But until the draft or inducer problem is corrected, the furnace will keep failing the retry sequence and relocking.
✓ Verified against manufacturer service manual — March 2026