Lennox EL296UHV Error Code E 224: Low Pressure Switch Failed Closed
What Does Code E 224 Mean?
Error code E224 on the Lennox EL296UHV indicates that the low pressure switch has remained closed for longer than 150 seconds during a heat call, which the control board interprets as a stuck switch. Normally, the pressure switch should only close when the combustion air inducer is running and creating sufficient draft.
A pressure switch that stays closed when it should be open is a safety concern because it could allow the ignition sequence to proceed even when proper venting draft has not been established. The control board monitors for this condition and flags it when the switch remains closed beyond the expected timeframe.
The most common cause is a mechanically stuck pressure switch diaphragm. Moisture from condensation can also cause the switch contacts to stick closed. Less commonly, incorrect wiring or a short in the pressure switch wiring harness can make the switch appear to be permanently closed. A technician should measure the operating pressure and inspect the switch for proper operation.
When to Call a Professional
Contact a licensed HVAC technician if:
- The pressure switch needs to be tested and likely replaced
- A technician should verify proper operating pressures
- The vent system and inducer should be inspected for related issues
✓ Verified against manufacturer service manual — March 2026