Which models this covers
Lennox EL296UHV and SL280UHV furnaces with ignition control 103130 (E-codes, Unit Information 1125 and SL280UHV instructions 508245), and ML180UHE furnaces with ignition controls 103217 and 107163 (flash codes, Unit Information 1120). Other Lennox models may differ. Codes differ between control boards, so check the code chart printed on your unit or in its manual if your model isn’t listed.
How to read the code
Read the code on the control board display through the furnace door window, or count the LED flashes on ML180 models (fast flashes, then a 3-second pause). Lennox lists these as technician diagnostics. The homeowner checks below are common, safe starting points.
E-codes (EL296UHV / SL280UHV)
| Code | What it means | What to do |
|---|---|---|
| E200 | Hard lockout: rollout circuit open or was open | Call a pro. A rollout trip can mean a blocked flue or cracked heat exchanger.Pro |
| E201 | Lost communication with indoor blower motor | Call a pro.Pro |
| E223 | Low pressure switch failed open | Check outdoor vent pipes for snow, ice or blockage. If clear, call a pro.Pro |
| E228 | Unable to calibrate pressure switch (inducer calibration failure) | Check vent pipes for blockage. Otherwise, call a pro to check venting and switch wiring.Pro |
| E241 | Flame sensed out of sequence | Shut off the gas to the furnace and call a pro (possible gas valve leak).Pro |
| E250 | Limit circuit open (airflow, blockage or firing rate) | Replace a dirty filter and open closed vents. It retries after a 1-hour lockout. If it repeats, call a pro.Pro |
| E270 | Soft lockout: maximum ignition retries, no flame current | Check the gas is on. If it repeats, call a pro (often the flame sensor or igniter).Pro |
| E290 | Igniter circuit fault (1-hour soft lockout) | Call a pro.Pro |
| E291 | Restricted airflow | Replace a dirty filter and make sure vents and returns aren’t blocked. |
| E292 | Blower motor can’t start (obstructed wheel or seized bearings) | Call a pro.Pro |
ML180 LED flash codes
| Code | What it means | What to do |
|---|---|---|
| 1 | Reversed line polarity | Call a pro or electrician.Pro |
| 2 | Improper ground | Call a pro or electrician.Pro |
| 3 | Burner failed to light, or lost flame | Check the gas is on. If it repeats, call a pro.Pro |
| 4 | Low flame signal | Call a pro. The flame sensor often needs cleaning.Pro |
| 5 | Watchguard lockout (retries/recycles exceeded) | Reset power. If it repeats, call a pro.Pro |
| 7 | Primary limit open | Replace a dirty filter and open vents. If it repeats, call a pro.Pro |
| 8 | Rollout switch open | Call a pro.Pro |
| 9 | Pressure switch failed to close, or opened | Check vent pipes for blockage. Otherwise, call a pro.Pro |
| 10 | Pressure switch opened 5 times in one heat cycle | Check vent pipes for blockage. Otherwise, call a pro.Pro |
| 11 | Pressure switch stuck closed | Call a pro.Pro |
| 12 | Flame sensed without gas valve energized | Turn off the furnace and call a pro.Pro |
| 13 | Low line voltage | Call a pro or electrician.Pro |
Sources
These codes are transcribed from the manufacturer’s own documentation. Many websites repeat codes that don’t match the manuals, so when in doubt, trust the chart on your unit.
- Lennox EL296UHV Unit Information 1125
- Lennox SL280UHV Installation Instructions 508245-01
- Lennox ML180UHE Unit Information 1120
Code pointing to a big repair? Check whether to repair or replace before you pay for it.
Frequently asked questions
What does E228 mean on a Lennox furnace?
E228 means the control couldn’t calibrate the pressure switch during inducer startup. Lennox points to venting and pressure switch wiring. Check the outdoor vent pipes for blockage, then call a pro. It isn’t a low-voltage code, as some sites claim.
What does E250 mean on a Lennox furnace?
E250 means the limit circuit opened because the furnace overheated, usually from restricted airflow. Replace a dirty filter and open closed vents and returns. The furnace retries after a 1-hour lockout. If it keeps happening, call a pro.
What does E270 mean on a Lennox furnace?
E270 is a soft lockout after the maximum number of ignition attempts with no flame detected. Make sure the gas is on. A recurring E270 usually means a dirty flame sensor, weak igniter or gas supply problem that a pro should check.