Lennox Furnace Igniter Not Working - Causes & Fix

Lennox Furnace Igniter Not Working — What’s Happening

When your Lennox furnace igniter isn’t working, the control board has detected an ignition failure during the normal startup sequence. The burners did not light after the standard retry attempts. Depending on your control board model, you may see code 228 or alternating quick flashes on the LED display, though the exact code pattern varies across Lennox platforms and should always be confirmed against the legend printed on your furnace door or in the service literature.

The furnace attempted to call for heat, energize the igniter, open the gas valve, and establish flame, but something in that chain failed. The most common single culprit is a hot surface igniter that has weakened, cracked, or broken and can no longer reach the roughly 1,800°F needed to ignite gas. Other frequent causes include closed or low gas supply, a dirty flame sensor that cannot confirm ignition, clogged burner ports, a failed gas valve, or a control board that isn’t sending power to the igniter circuit.

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Most Likely Causes

• Cracked or failed hot surface igniter The ceramic igniter element develops hairline cracks or breaks completely, preventing it from reaching ignition temperature even when voltage is applied.
• Gas supply interrupted or insufficient The manual gas valve at the furnace is closed, the utility has low pressure, or the propane tank is empty, so no fuel reaches the burners.
• Dirty or corroded flame sensor Carbon buildup or corrosion on the flame rod prevents the board from confirming ignition, causing the sequence to shut down and retry.
• Clogged burner ports Rust, dust, spider webs, or other debris block gas flow through the burner orifices, preventing proper flame establishment even when the igniter glows.
• Failed gas valve The valve does not open when commanded by the control board, so gas never flows to the burners despite a glowing igniter.
• Control board not supplying igniter voltage A faulty board, blown fuse, loose connector, or broken wire in the igniter harness prevents the roughly 120 VAC needed to heat the igniter from reaching the element.
• Loose or corroded wiring and connectors Igniter harness plugs, Molex connectors, or wire splices develop high resistance or intermittent contact, interrupting power to the igniter or signals to the board.

How to Diagnose and Fix

1. Identify the exact error code or LED flash pattern from the legend on your furnace blower-door label or control board, and confirm it points to ignition failure rather than pressure switch, flame sense, or another fault.
2. Check the circuit breaker and furnace fuse, then cycle power once to clear any transient fault and observe whether the ignition problem returns immediately on the next heat call.
3. Verify gas supply by confirming the manual gas valve upstream of the furnace is fully open, checking that other gas appliances in the home operate normally, and if on propane confirming the tank has fuel.
4. Observe a full ignition trial with the furnace calling for heat: note whether the igniter glows bright orange, whether you hear the gas valve click and gas flowing, and whether burners light briefly then drop out or never light at all.
5. Turn off power at the breaker and the furnace switch, disconnect the igniter plug at the harness, and use a multimeter to check continuity or resistance across the igniter terminals to confirm the element is intact, then inspect the plug and wiring for damage or corrosion.
6. Reconnect the igniter, restore power, initiate a heat call, and carefully measure voltage at the igniter connector during the ignition trial to confirm the control board is supplying approximately 120 VAC to the igniter circuit.
7. If the igniter tests good and receives voltage but burners still do not light, inspect the flame sensor rod for heavy carbon or corrosion, clean it gently with fine steel wool or a ScotchBrite pad, and confirm it is positioned in the flame path per the installation manual.
8. Check the burner assembly for rust, debris, or blocked ports that could prevent proper flame spread, and if you find gas-valve or control-board faults beyond igniter and sensor issues, call a qualified HVAC technician to complete gas-system and electrical diagnostics safely.

Parts You Might Need

Related Error Codes

If your appliance also shows a code on the display, these match this problem:

• Lennox Furnace E117 error code
• Lennox Furnace E125 error code
• Lennox Furnace E204 error code
• Lennox Furnace E205 error code
• Lennox Furnace E206 error code
• Lennox Furnace E227 error code
• Lennox Furnace E241 error code
• Lennox Furnace E250 error code
• Lennox Furnace E270 error code
• Lennox Furnace E275 error code
• Lennox Furnace E290 error code

When to Call a Pro

If you are not comfortable working around 120 VAC wiring, natural gas, or propane, or if your local code requires a licensed technician for any gas-appliance repair, call an HVAC professional before beginning. Similarly, if you have confirmed the igniter element is intact and receives voltage but the burners still do not light, the fault likely lies in the gas valve, burner assembly, flame-sensor circuit, or control-board logic, all of which require gas-system knowledge and combustion-analyzer testing to diagnose safely. Any time you smell gas, hear a continuous hiss, or suspect a gas leak, leave the home immediately and call your utility or fire department, then arrange for a qualified technician to inspect and repair the furnace. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.

See Also

• Lennox Error Code 540 — Causes & Fix
• Lennox Furnace Won’t Turn On - Causes & Fix
• Lennox iComfort Error Code 31 — Pressure Switch Fault Diagnosis and Fix
• Lennox Error Code 432 — Causes & Fix