Lennox E200 Error Code

What does Lennox E200 mean?

E200 is a hard lockout triggered when the furnace flame rollout switch opens or has previously opened. The rollout switch is a one-time or manual-reset safety device that trips when flames escape the burner box — indicating a dangerous combustion fault. The furnace will not restart until the underlying cause is corrected and the rollout switch is reset or replaced.

Symptoms

• Furnace shuts down completely and will not restart without manual intervention.
• E200 alert displayed on thermostat or control board LED.
• Visible scorch marks or soot around the burner area or heat exchanger.
• Rollout switch trips repeatedly on successive restart attempts.

Common causes

• Blocked or restricted heat exchanger causing combustion gases to roll out.
• Blocked flue or vent pipe preventing proper exhaust, forcing flames backward.
• Combustion air inducer failure reducing draft and allowing rollout.
• Cracked heat exchanger allowing combustion products to spill into the plenum.
• Improper gas pressure or burner orifice causing oversized flame.

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Diagnostic steps

1. Identify and correct the root cause of rollout

   Do not simply reset the switch and restore operation. Inspect the flue system, heat exchanger, inducer motor, and burner assembly for the condition that caused flames to escape the firebox.

2. Inspect the vent system for blockages

   Check PVC vent pipes for debris, ice, bird nests, or collapsed sections. Clear any obstruction and verify proper pitch and termination clearance per the SL280DFNV installation instructions.

3. Check combustion air inducer operation

   With the furnace in diagnostic mode, verify the inducer motor reaches proper speed and produces the expected draft pressure. A weak or failed inducer can cause rollout even with an unobstructed flue.

4. Reset or replace the rollout switch

   After correcting the root cause, press the manual reset button on the rollout switch. If the switch is a non-resettable type or has tripped multiple times, replace it with the Lennox OEM part.

5. Test full heating cycle and monitor for recurrence

   Run the furnace through a complete heat demand cycle. If the rollout switch trips again, shut down immediately — a cracked heat exchanger or severe vent restriction requires further diagnosis before returning the unit to service.

When to call a professional

E200 is a hard lockout for a reason — flame rollout is a carbon monoxide and fire hazard. If you cannot identify and eliminate the root cause, or if the rollout switch trips again after reset, shut off the furnace and call a licensed technician immediately. A cracked heat exchanger in particular requires combustion analysis equipment and pressure testing to confirm, and the unit must remain offline until the fault is resolved.