Lennox E223 Error Code: Low pressure switch failed to close
Updated October 2026 · Sourced from Lennox documentation
🛑 Turn it off and call a licensed pro
The low pressure switch failed to close (stuck open) when the furnace called for heat.
Is it safe to keep running? No. Turn it off and get it checked. Call a licensed HVAC technician. The pressure switch, venting and inducer need professional testing.
E223 at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| E223 Shown as an E code on the 7-segment display of the integrated control | Low pressure switch failed to close | Lennox SL280UHVK two-stage variable-speed furnace (integrated control, 7-segment display) |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- Look outside at the furnace vent and intake pipes for snow, leaves, nests or other blockage, and clear anything you can reach safely.
- Check that the condensate drain line is not visibly blocked, kinked or overflowing.
- Replace a dirty air filter, then restore power and see if the code returns.
- Turn the furnace power switch or breaker off for 30 seconds, then back on, and see if the code clears.
🛑 Stop and call a licensed pro if
- Call a licensed HVAC technician. The pressure switch, venting and inducer need professional testing.
- You smell gas. Leave the house, do not touch switches, and call your gas utility from outside.
- Flame rollout, limit or pressure switch codes that come back after one reset.
- Anything involving the control board, gas valve, flame sensor, igniter or venting.
- A carbon monoxide alarm sounds. Get everyone outside and call 911 or the fire department.
Safe first steps for any Lennox code
- Count the LED flashes through the blower door window before you switch anything off. Cutting power can clear the code.
- Replace or clean the furnace air filter.
- Check the thermostat: correct mode, set above room temperature, and fresh batteries.
- Make sure the furnace power switch and breaker are on. If the furnace has locked out, turning the power off and back on once restarts it.
- Make sure the gas valve is in the ON position, following the lighting instructions on the furnace label only.
- On high-efficiency furnaces, look at the outside vent and intake pipes for snow, ice, leaves or nests (look only, do not take pipes apart).
Source: Lennox SL280UHVK Installation Instructions 508553-01 (01/2025), Ignition Control Diagnostic Codes, p.36. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
Shaun Cain · Certified HVAC & Refrigeration Technician · Ask an HVAC technician
Related Lennox codes
E110 : AC line voltage lowE111 : Line voltage polarity reversedE112 : Earth ground not detectedE113 : AC line voltage highE115 : Low 24V control voltageE200 : Rollout open (hard lockout)E204 : Gas valve relay problemE206 : Gas valve second-stage relay problemE224 : Low pressure switch failed to openE225 : High pressure switch failed to closeE226 : High pressure switch failed to openE227 : Low pressure switch opened during run