CRITICAL URGENCY
Lennox E200 - Rollout Switch Open (SAFETY)
E200 (or 200)
Hard lockout - flame rollout circuit open. Get inspected before reset.
Brand: Lennox (Also covers Armstrong Air, Aire-Flo, Ducane) | Equipment: Gas Furnace
SAFETY: Cracked heat exchanger releases carbon monoxide. CO is odorless and colorless. Evacuate and call 911 if anyone has headache, dizziness, or nausea.
What This Code Means
Error code E200 on Lennox iComfort and SLP/SL/EL series communicating furnaces means the flame rollout switch has tripped (hard lockout). Flames escaping the burner enclosure - serious combustion problem.
Likely Causes (Ranked)
Common and serious
Cracked heat exchanger
What: Crack lets flames escape from burner box.
How to check: Licensed tech inspection only.
Fix: Heat exchanger or furnace replacement.
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Common on 90%+ AFUE
Plugged secondary heat exchanger
What: Condensate buildup blocks passages, causing backpressure.
How to check: Tech inspection.
Fix: Clean or replace.
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Common
Blocked exhaust vent
What: Snow, ice, debris, or disconnected vent pipe.
How to check: Inspect outdoor exhaust outlet.
Fix: Clear blockage.
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Less common
Failed inducer motor
What: Poor draft causes flame disruption.
How to check: Listen at startup.
Fix: Replace inducer.
Shop parts
Diagnostic Steps
- STOP - do not keep resetting
- Shut off gas at furnace
- Verify CO detector working
- Call licensed HVAC tech
Frequently Asked Questions
How urgent is Lennox E200?
Very urgent - safety critical. The rollout switch tripped because flames are escaping the burner box. Do not operate the furnace until inspected.
Can I reset and keep running?
No - CO risk with cracked heat exchanger. Get an inspection first.
Same code on Armstrong/Ducane?
Yes - Lennox family iComfort/communicating series uses identical codes.
Related Lennox Codes
Related Symptoms
Need More Help?
Try our interactive symptom diagnostic tool or browse Lennox parts.