HeatingCodesLennox furnace code E223: low pressure switch failed open (also E227, E271, E272)
What E223 means
Lennox defines E223 as Low pressure switch failed open. The low pressure switch confirms that the combustion air inducer is creating enough draft before burners light. The manual's corrective action says: "Check pressure (inches w.c.) of low pressure switch closing on heat call. Measure operating pressure. Inspect vent and combustion air inducer for correct operation and restriction." It "resumes normal operation after fault is cleared."
The pressure switch family in the Lennox table
| Code | Meaning (per Lennox) |
|---|---|
| E223 | Low pressure switch failed open |
| E224 | Low pressure switch failed closed. Check whether it is stuck closed on a heat call longer than 150 seconds. |
| E225 | High pressure switch failed open |
| E226 | High pressure switch failed closed |
| E227 | Low pressure switch open during trial for ignition or run mode |
| E228 | Combustion air inducer calibration failure: unable to perform pressure switch calibration. Check the vent system and pressure switch wiring. |
| E271 | Soft lockout: exceeded maximum retries, last retry failed because the pressure switch opened. Clears when the heat call finishes successfully. |
| E272 | Soft lockout: exceeded maximum recycles, last recycle due to the pressure switch opening. Clears when the heat call finishes successfully. |
| E229 | Ignition on high fire. The control switched to high-fire ignition because the low-fire switch did not close in time. Lennox says no action is needed. |
E229 is worth pointing out because it is not a problem code at all. If you only see E229 and the furnace is heating, Lennox says no action is needed.
Why a frozen or blocked vent is the first suspect
The pressure switch opens when the inducer cannot move air normally. A restricted vent or intake pipe is a standard reason. Heavy snow around a wall termination, ice on the pipe opening, a bird nest or a pipe that has sagged can all restrict flow. Lennox tells the technician to inspect the vent and inducer for restriction, and a homeowner can look at the outdoor ends of the pipes from the ground.
Safe homeowner checks for Lennox furnace code E223
- Turn the thermostat offStop the heat call before you go outside.
- Check the outdoor vent and intake terminationsFrom the ground, clear snow, ice, leaves or nests from the two plastic pipes that exit the house. Do not climb on the roof or remove the pipes.
- Restart onceTurn the thermostat to heat. E223 may clear after a heat call finishes successfully.
- Call a technician if the code repeatsDo not open the furnace or touch the pressure switch hose. A technician can measure the switch and inspect the inducer.
Frequently asked questions
What does it mean when the inducer runs but the furnace does not light?
The control is waiting for the pressure switch to close. If the switch stays open, the control will not open the gas valve. Lennox says to check the switch pressure and inspect the vent and inducer.
Is E223 the same as a Goodman EE2?
They describe the same kind of fault on different brands: a low-stage or low pressure switch that is not closing. The codes and the exact controls are different, so use the table for your own furnace.
Can I replace the pressure switch myself?
This is a safety device on a gas appliance, and it should be diagnosed and replaced by a qualified technician.
Sources
- Installation Instructions 508246-01 (04/2024): SL280DFV Elite Series gas furnace, Integrated Control Diagnostic Codes (Lennox) Covers: Lennox SL280DFV variable-capacity condensing gas furnaces with the integrated control described in the document. Other Lennox furnace lines can use different code sets.
Safety note: this page is general information drawn from the sources above. Gas, combustion and line-voltage repairs belong to a licensed professional. Your own equipment's label and manual take priority over anything here. Read the full disclaimer.