Quick answer
Lennox furnace error code E228 means combustion air inducer calibration failure: the control was unable to perform its pressure-switch calibration. The furnace will not run a heat cycle until calibration succeeds. Clear the intake and exhaust terminations outside, then cycle power once so the control re-attempts calibration. If E228 returns, the vent system and pressure-switch wiring connections need a technician.
E228 is the Lennox furnace error code for a combustion air inducer calibration failure. Lennox's diagnostic table for the EL296DFV describes it as the control being unable to perform its pressure-switch calibration. In plain terms, the furnace tested its own draft system before heating and could not complete the test. Check the code legend on the label inside the panel, because Lennox does not use the same table on every model.
What the calibration is, and why there is no heat without it
The furnace will not run a heat cycle until calibration succeeds. Calibration is the control's check that the combustion air inducer and the pressure switches respond the way they should before it commits to lighting the burners. When the result does not make sense, the control refuses to guess.
That makes E228 a no-heat code, not a nuisance code. It also means the furnace is not firing in a doubtful state while the code is showing; it is simply not firing.
How fast you need help follows from that. With the house holding temperature and mild weather outside, a booked visit is fine. With the outdoor temperature below 0°C and no second heat source, treat E228 as a no-heat call and phone the 24/7 line at (647) 801-1252; there is no after-hours surcharge.
The one reset worth doing for E228
Cycling power makes the control re-attempt calibration, so one reset has a purpose here. Do it only after the outdoor pipes are clear, otherwise the control repeats the same failed test.
- Go outside and clear snow, ice and debris from both the intake and the exhaust termination.
- Back at the furnace, switch the power off at the furnace switch or the breaker.
- Wait 30 seconds and switch it back on.
- Leave the thermostat calling for heat and give the furnace several minutes without touching it.
- If E228 returns, stop. A second and third power cycle will not change the result.
Causes of an E228 calibration failure, most likely first
- A restriction or a leak in the vent system. A blocked termination starves the inducer; a glued joint that has pulled apart lets it draw air from the wrong place.
- Pressure-switch wiring or hose faults: a connector that has backed off its terminal, or a hose that is split, kinked or off its port.
- Condensate in the tubing. A few drops of water in a pressure-switch hose are enough to distort what the switch feels.
- A failing inducer that can no longer produce the draft the control expects.
Vent problems can trace back to other work in the house. In 1970s to 1990s subdivision homes where the basement has since been finished, the plastic vent run is sometimes boxed in behind drywall or rerouted around a new wall, and a joint disturbed during that work can sit unnoticed until the furnace complains. Tell the technician about any renovation near the furnace or along the pipe route.
What a technician checks on the vent system and switch wiring
Lennox's table points to two places for E228: the vent system and the pressure-switch wiring connections. A technician inspects the full vent run for blockage, separation and sag, then checks each pressure switch connector and hose, drains any water from the tubing, and measures the draft with a manometer while the inducer runs.
If the vent and wiring are sound and the draft is still short, the inducer itself is tested. What a furnace inducer motor costs covers that repair in detail. A related code, E223, means the low pressure switch failed open and shares several of these causes.
- Diagnosis: $90–$150, applied to the repair if you go ahead with it
- Pressure switch: $250–$500 installed
- Draft inducer motor: $400–$900 installed
- Vent repairs: quoted in writing once the run has been inspected, because the price depends on access and length
A furnace showing E228 after one clean reset needs hands on it. Have the model and serial number from the rating plate ready, and mention whether the code first appeared after a storm, a power outage or work on the house.ZK Mechanical's TSSA-licensed technicians service Lennox equipment across Burlington, Oakville, Milton, Hamilton and Mississauga; book furnace repair or contact us with the model number. Other codes on the same display are listed in the Lennox furnace error code guide.