Lennox E227 Error Code — What It Means
The E227 fault on a Lennox furnace indicates a pressure switch problem. The control board sees the pressure switch stuck open or stuck closed instead of changing state as expected during the draft-proving sequence. In normal operation, the inducer motor creates airflow that causes the pressure switch to close, signaling safe draft conditions. When the switch does not respond correctly, the furnace locks out and displays E227.
This code means the switch is either not opening or closing when it should, or the control is not detecting the expected pressure signal. The exact behavior can vary by furnace series. The available troubleshooting documentation shows Lennox SL280 models, but the core principle applies across Lennox platforms that use electronic pressure proving.
Common Causes
- Blocked or clogged pressure tubing The small rubber or vinyl hose running from the inducer to the pressure switch becomes obstructed by condensation, debris, or kinks, preventing the switch from sensing draft.
- Debris in the pressure port or orifice Lint, rust, soot, or other particles plug the port at the inducer housing or collector box connection, blocking the pressure signal path.
- Failed pressure switch The switch itself has bad contacts, a stuck diaphragm, or a mechanically jammed mechanism that prevents it from changing state reliably.
- Inducer motor or blower airflow problems The inducer does not run properly or the venting path is obstructed, so the required draft pressure is never generated to close the switch.
Step-by-Step Fix
- {‘lead’: ‘Confirm the error code and observe the startup sequence’, ‘text’: ‘Turn off power to the furnace at the disconnect switch and the circuit breaker. Wait 30 seconds, then restore power. Initiate a call for heat at the thermostat and watch the inducer stage. Note when the E227 fault appears, typically during the pressure-switch proving period before ignition.’}
- {‘lead’: ‘Inspect and clean the pressure tubing’, ‘text’: ‘Locate the small rubber or vinyl hose that runs from the inducer housing to the pressure switch. Check for cracks, disconnections, kinks, or water inside the tube. Remove the tubing and blow through it to verify it is clear. Replace the tubing if damaged or heavily clogged.’}
- {‘lead’: ‘Clear the pressure port and orifice’, ‘text’: ‘Find the pressure tap or port on the inducer housing or collector box where the tubing connects. Remove any lint, rust, soot, or debris from the port opening using a small brush or compressed air. Be careful not to push debris further into the assembly.’}
- {‘lead’: ‘Check inducer motor operation and airflow’, ‘text’: ‘Verify that the inducer motor spins freely and runs when the furnace calls for heat. Inspect the venting path for blockages, nests, or icing that would restrict draft. Listen for normal airflow sound from the inducer. If the inducer does not run or sounds weak, further motor or wiring diagnosis is required.’}
- {‘lead’: ‘Test the pressure switch electrically and mechanically’, ‘text’: ‘With power off, disconnect one wire from the pressure switch and use a multimeter to check continuity across the switch terminals. The switch should be open (no continuity) when no draft is present. Apply suction manually to the switch port or run the inducer to create draft. The switch should close (show continuity). If the switch does not change state with verified draft, it is faulty.’}
- {‘lead’: ‘Replace the pressure switch if defective’, ‘text’: ‘Turn off all power. Remove the old pressure switch by disconnecting the wiring harness and pressure tubing, then unbolting or unclipping the switch bracket. Install the new switch in the same orientation, reconnect the tubing securely, and restore the wiring connections. make sure the tubing is not kinked.’}
- {‘lead’: ‘Restore power and verify operation’, ‘text’: ‘Turn the furnace back on and initiate a full heat call. Watch the inducer run and listen for the pressure switch to click closed. The furnace should proceed through ignition and enter normal heating without displaying E227. Cycle the furnace off and on at least twice to confirm consistent operation.’}
Parts Often Needed
| Part | Notes |
|---|---|
| Lennox pressure switch | Amazon | Match the part number on your existing switch label or consult your furnace model’s service manual for the correct replacement. |
| Pressure switch tubing (vacuum hose) | Amazon | Use tubing of the same inner diameter and material as original, typically 1/4-inch clear vinyl or rubber rated for furnace use. |
| Inducer motor assembly | Amazon | Required only if the inducer does not run or cannot generate proper draft after clearing blockages and verifying the pressure switch. |
When to Call a Pro
Call a licensed HVAC technician if you are not comfortable working with electrical components, gas appliances, or furnace controls. If you have cleared the tubing and ports but the E227 code persists, a technician can perform detailed pressure measurements, verify control board signals, and diagnose intermittent switch or inducer faults. Professional service is also recommended if the inducer motor requires replacement, if you suspect a venting or combustion airflow problem, or if the furnace has other active fault codes. Always follow local codes and manufacturer requirements for gas furnace service.