Lennox EL296UHV Error Code E 227: Low Pressure Switch Open During Operation
What Does Code E 227 Mean?
Error code E227 on the Lennox EL296UHV means the low pressure switch opened during the trial for ignition or during run mode. This is different from E223, where the switch never closes at all: with E227 the low switch DID close and prove low-fire draft, and then dropped out partway through the cycle. When that happens the SureLight control immediately closes the gas valve, because losing draft during combustion means exhaust may no longer be vented safely.
Because the EL296UHV is a two-stage furnace, the low pressure switch is the one proving draft at the low firing rate throughout the burn. An opening mid-cycle tells the control that draft momentarily fell below the switch's holding point. Typical causes are a marginal or intermittent vent blockage, a weakening inducer that cannot hold steady draft as the system heats, condensate collecting in the pressure-switch hose, or gusting wind and downdraft pushing back against the exhaust termination. Ice that gradually restricts the vent as a cycle runs is a common winter trigger.
E227 is closely related to E223 (low switch fails to close at startup) and can escalate to soft-lockout codes if it repeats: E271 covers pressure-switch retries failing during ignition, and E272 covers the switch repeatedly opening during operation. The furnace will try to restart, but persistent dropouts will push it into lockout. The furnace resumes normal operation once the fault is cleared.
What You'll Notice
- The furnace lights and runs briefly, then shuts down partway through the cycle
- The seven-segment display shows E227
- Failures are intermittent and more common during windy or gusty weather
- Short heating cycles that end before the space warms up, sometimes with repeated restarts
- The problem comes and goes rather than failing the same way every time
How This Is Diagnosed
A technician watches the low pressure switch through a full cycle while reading draft on a manometer (in inches of water column), looking for the moment draft dips below the switch's holding point. A reading that starts adequate and then sags points to a weakening inducer or a restriction that worsens as the system heats; a stable reading with an opening switch points to the switch or a hose problem.
They inspect the vent and intake path for marginal restrictions, check the pressure-switch hose for condensate or a loose fit at the inducer port, and evaluate whether the vent termination is exposed to wind or downdraft that can momentarily spoil draft. This is diagnostic information only; the corrective work is on the sealed venting and combustion system and is not a homeowner task.
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 but shuts down shortly after, with the display showing E227
- The fault happens intermittently, especially in windy or gusty weather
- The outdoor vent terminations look clear but E227 keeps recurring
- The inducer sounds inconsistent or seems to change speed during a cycle
- E227 is followed by E271 or E272 (pressure-switch soft lockouts)
Frequently Asked Questions
How is E227 different from E223?
E223 means the low pressure switch never closed to begin with, so the furnace never lights. E227 means the switch closed and proved draft, then opened during the ignition trial or run, so the furnace lights and then shuts down.
Why does wind seem to trigger E227?
Gusts and downdraft at the exhaust termination can momentarily push back against the flue and drop draft below the low switch's holding point. The control reads that as a loss of safe venting and shuts the burners off.
Is it safe to keep resetting the furnace when E227 appears?
Repeatedly restarting masks a real loss of draft during combustion, which is a venting safety concern, and it can drive the board into a soft lockout. The underlying restriction, inducer weakness, or draft problem should be diagnosed by a technician.
✓ Verified against manufacturer service manual — March 2026