Lennox EL296UHV Error Code E 223: Low Pressure Switch Failed Open

What Does Code E 223 Mean?

Error code E223 on the Lennox EL296UHV indicates that the low pressure switch failed to close during a call for heat. The pressure switch is a safety device that confirms the combustion air inducer is creating enough draft to safely vent exhaust gases before the burners are allowed to ignite.

When the inducer motor starts, it pulls air through the heat exchanger and out the exhaust vent, creating negative pressure. The low pressure switch senses this draft and closes its contacts. If the switch does not close, the SureLight control blocks ignition and displays this error code. The furnace resumes normal operation once the fault is cleared.

The most common cause is a blocked or restricted exhaust vent or combustion air intake. In winter, ice can form around the vent termination; bird nests, insect nests, leaves, and other debris can also block the vent at any time of year. Other causes include a failing inducer motor that cannot generate sufficient draft, a cracked or disconnected pressure switch hose, or a faulty pressure switch.

Common Causes

How to Fix It: Inspect and Clear the Exhaust and Intake Vents

What You'll Need

• Flashlight
• Ladder (if vent terminates above ground level) Find on Amazon
• Work gloves Find on Amazon

Steps

1. Turn off electrical power and gas supply Turn off the furnace at the circuit breaker. Turn the gas shutoff valve to the OFF position (handle perpendicular to the pipe). If you smell gas at any point, leave the area immediately and call your gas company.
2. Locate the exhaust and intake vent terminations outside Find where the PVC exhaust and intake pipes exit your home. On the EL296UHV, these are typically two PVC pipes (2 or 3 inch) exiting through a side wall. The exhaust pipe is the one connected to the inducer motor; the intake brings in combustion air.
3. Check for blockages at both vent terminations Use a flashlight to look into both pipe openings. Remove any visible debris such as ice, snow, leaves, bird or insect nests, or other obstructions. In winter, check for ice buildup around the vent screens or openings. Clear both pipes — a blocked intake can cause the same symptom as a blocked exhaust.
4. Inspect the pressure switch hose inside the furnace Open the furnace access panel and locate the small rubber hose connecting the low pressure switch to the inducer housing. Verify it is firmly connected at both ends, not cracked, split, or kinked. A disconnected or damaged hose prevents the switch from sensing draft.
5. Restore power and gas, then test Turn the gas supply valve to ON (handle parallel to the pipe) and flip the circuit breaker to ON. Set your thermostat to call for heat and listen for the inducer motor to start, followed by ignition.

When to Call a Professional

Contact a licensed HVAC technician if:

• The vents appear clear but E223 persists
• The inducer motor sounds weak, rattles, or does not start
• The pressure switch hose is intact but the switch still will not close
• You see E271 (soft lockout from repeated pressure switch failures)
• The vent run is unusually long or has excessive elbows

✓ Verified against manufacturer service manual — March 2026