Lennox Furnace Code E228: What It Means & How to Fix It
Compiled & reviewed by the HVAC Flash Codes editorial team · Updated 2026-06-25 · confidence: high
⛔ Stop — call a licensed pro
What does Lennox furnace code e228 mean?
Combustion-air inducer / pressure-switch calibration failure — the control is unable to calibrate the pressure switch. A 'Service Soon' condition that auto-clears after a successful calibration. Most often caused by Blocked or restricted intake/exhaust (PVC) vent piping.
E228
What your control shows. Your Lennox furnace displays Code E228 on its diagnostic readout.
What Lennox furnace code e228 means
Combustion-air inducer / pressure-switch calibration failure — the control is unable to calibrate the pressure switch. A 'Service Soon' condition that auto-clears after a successful calibration.
Common causes
Blocked or restricted intake/exhaust (PVC) vent piping
Cracked, kinked, or disconnected pressure-switch hoses
Inducer or pressure-switch fault
Homeowner-safe steps to try
Set the thermostat to OFF
From outside, check the intake/exhaust pipe terminations and clear ice, snow, leaves, or nests
Confirm the condensate drain line isn't visibly clogged or kinked
Replace a dirty air filter, confirm vents are open, and cycle power to let the control re-calibrate
When to call a licensed HVAC technician
If the basic checks below don't clear the code, the fault recurs, or anything involves the gas valve, burners, flame sensor or wiring, stop and book a licensed HVAC technician. Repairs to the combustion or gas system are not DIY.
⚠️ Safety first. Gas furnaces burn fuel and produce combustion gases. If you ever smell gas (a rotten-egg or sulfur odor), hear hissing, or your carbon-monoxide alarm sounds, do not touch light switches, thermostats, or the furnace — leave the home immediately and call your gas utility's emergency line or 911 from outside. Homeowners should limit themselves to simple, safe steps: setting the thermostat, checking and replacing the air filter, confirming the furnace switch and breaker are on, keeping supply registers and return grilles open, and clearing snow, ice, or debris from outdoor vent and intake terminations. Never bypass, jumper, or reset safety switches (limit, flame-rollout, or pressure switches), never open the gas valve or burner compartment, and never attempt combustion, electrical, or control-board repairs yourself. Error codes point toward a problem but are not a substitute for proper diagnosis — when in doubt, turn the system off and call a licensed HVAC technician. Keep working carbon-monoxide detectors on every level of your home.
When to call a pro: Call a licensed technician if the code persists after vents and drain are confirmed clear, or to inspect the pressure-switch hoses, inducer, or pressure switch. Do not open the burner compartment or touch the gas valve. If you smell gas, leave and call your gas utility from outside.
Lennox furnace code e228 FAQ
What does Lennox furnace code e228 mean?
Combustion-air inducer / pressure-switch calibration failure — the control is unable to calibrate the pressure switch. A 'Service Soon' condition that auto-clears after a successful calibration.
What causes Lennox furnace code e228?
Common causes: Blocked or restricted intake/exhaust (PVC) vent piping; Blocked condensate drain or plugged cold-end heater box / drain strainers; Cracked, kinked, or disconnected pressure-switch hoses; Inducer or pressure-switch fault.
Can I fix Lennox furnace code e228 myself?
You can safely try: Set the thermostat to OFF; From outside, check the intake/exhaust pipe terminations and clear ice, snow, leaves, or nests; Confirm the condensate drain line isn't visibly clogged or kinked; Replace a dirty air filter, confirm vents are open, and cycle power to let the control re-calibrate. Call a licensed technician if the code persists after vents and drain are confirmed clear, or to inspect the pressure-switch hoses, inducer, or pressure switch. Do not open the burner compartment or touch the gas valve. If you smell gas, leave and call your gas utility from outside.
Sources: lennox.com · lennox.com. General information for homeowners, not professional advice — confirm against your furnace's manual and a licensed technician.