Lennox EL296UHV Error Code E 223: Low Pressure Switch Failed Open
What Does Code E 223 Mean?
Error code E223 on the Lennox EL296UHV means the low pressure switch failed to close on a call for heat. Because the EL296UHV is a two-stage furnace, it carries both a low and a high pressure switch: the low switch proves that the combustion-air inducer is pulling adequate draft at the low firing rate before the burners are allowed to light. When the inducer spins up but the low switch never senses enough negative pressure to close its contacts, the control halts ignition and posts E223.
The most common reason is a blocked or restricted exhaust vent or combustion-air intake. Ice at the vent termination in winter, leaves, insect or bird nests, or a sagging pipe section can all choke the airflow the inducer needs. A weakening inducer motor that no longer moves enough air, a cracked or disconnected pressure-switch hose, or a failed switch will produce the same result because in every case the switch cannot see the draft it expects.
E223 sits at the low-fire end of a family of pressure-switch codes on this board. It is the opposite condition to E224, where the low pressure switch is stuck CLOSED at rest, and it precedes E227, where the low switch closes normally but then OPENS during the ignition trial or run. Repeated E223-type failures can escalate the control into E271, a soft lockout after the pressure-switch retries are exhausted. The furnace resumes normal operation once the underlying fault is cleared.
What You'll Notice
- No heat, with the inducer motor audibly running for a few seconds before the furnace shuts down without lighting
- The seven-segment display shows E223
- The furnace tries again after a delay but repeats the same short inducer-only cycle
- More frequent failures during storms, high wind, or freezing weather when the vent can ice over
- The cycle never reaches the whoosh of burner ignition or the main blower turning on
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Blocked or restricted vent or combustion air intake | Most common | ✗ Call a pro → |
How This Is Diagnosed
A technician first confirms the low pressure switch is genuinely open at rest and then watches whether it closes when the inducer runs. Using a manometer, they measure the actual draft (in inches of water column) the inducer develops on the low firing rate and compare it against the switch's rated closing pressure printed on the switch body. If the draft is adequate but the switch will not close, the switch or its wiring is suspect; if the draft is low, the problem is upstream.
They then inspect the full vent and intake path and the inducer itself: the PVC exhaust and intake terminations outside, the pipe run for sags or restrictions, and the pressure-switch hose for cracks, kinks, condensate, or a loose fit at the inducer port. A weak or noisy inducer wheel that cannot generate rated draft is confirmed by the low manometer reading. This is diagnostic information only; the corrective work involves the sealed combustion and venting 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 runs the inducer briefly, then shuts off without lighting, and the display shows E223
- The vent terminations outside look clear but the code keeps returning
- The inducer motor sounds weak, rattles, or hums without spinning up fully
- E223 appears alongside E271 (soft lockout after pressure-switch retries fail)
- The failures cluster during high wind or freezing weather
Frequently Asked Questions
Why does the furnace start the inducer but never light the burners?
On the EL296UHV the burners are only allowed to fire after the low pressure switch confirms safe draft. With E223 the switch never closes, so the SureLight control keeps the gas valve shut and ends the cycle before ignition.
Could a blocked vent really be the cause even though nothing looks wrong inside?
Yes. The restriction is frequently at the outdoor exhaust or intake termination, or inside a sagging pipe run, rather than at the furnace. A partial blockage can be enough to keep draft below the switch's closing threshold.
Is E223 dangerous?
The code itself is the safety system working as intended: it prevents the furnace from firing when it cannot prove adequate venting. The concern is the underlying restriction or inducer weakness, which a technician should identify and correct.
✓ Verified against manufacturer service manual — March 2026