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 indicates that the low pressure switch opened during the trial for ignition or while the furnace was actively running. This is different from the switch failing to close initially — it closed and then opened, meaning venting conditions changed during operation.
When the pressure switch opens mid-operation, the control board immediately shuts off the gas valve as a safety measure. Losing draft during combustion means exhaust gases may not be properly vented, which creates a carbon monoxide risk. The furnace will attempt to restart, but if the switch continues to open during operation, it will eventually enter a soft lockout.
Common causes include intermittent vent blockages such as wind gusts pushing back against the exhaust, a partially blocked vent that allows startup but restricts flow as heat builds, condensation accumulating in the pressure switch hose, or an inducer motor that is weakening and cannot maintain consistent draft. Ice buildup at the vent termination that gradually restricts exhaust flow is a common winter cause.
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace starts but shuts down shortly after ignition
- E227 occurs intermittently, especially during windy conditions
- You have checked the vent termination and found no obvious blockages
- The inducer motor sounds inconsistent or changes speed during operation
✓ Verified against manufacturer service manual — March 2026