Lennox Furnace Code E200: What It Means & How to Fix It
Compiled & reviewed by the HVAC Flash Codes editorial team · Updated 2026-06-25 · confidence: high
⛔ Stop — call a licensed pro
What does Lennox furnace code e200 mean?
Rollout circuit open — a hard lockout indicating the flame-rollout safety opened (flame or heat escaped the burner box). The furnace locks out for safety and should not be run until inspected. Most often caused by Blocked heat exchanger or restricted/blocked venting.
E200
What your control shows. Your Lennox furnace displays Code E200 on its diagnostic readout.
What Lennox furnace code e200 means
Rollout circuit open — a hard lockout indicating the flame-rollout safety opened (flame or heat escaped the burner box). The furnace locks out for safety and should not be run until inspected.
Common causes
Blocked heat exchanger or restricted/blocked venting
A cracked or failed heat exchanger
Dirty burners or poor combustion
Inducer failure
Homeowner-safe steps to try
Set the thermostat to OFF and leave the furnace off
Do NOT keep cycling power to force it to run
Record the code and call a professional — this is not a homeowner-serviceable fault
When to call a licensed HVAC technician
If the basic checks below don't clear the code, the fault recurs, or anything involves the gas valve, burners, flame sensor or wiring, stop and book a licensed HVAC technician. Repairs to the combustion or gas system are not DIY.
⚠️ Safety first. Gas furnaces burn fuel and produce combustion gases. If you ever smell gas (a rotten-egg or sulfur odor), hear hissing, or your carbon-monoxide alarm sounds, do not touch light switches, thermostats, or the furnace — leave the home immediately and call your gas utility's emergency line or 911 from outside. Homeowners should limit themselves to simple, safe steps: setting the thermostat, checking and replacing the air filter, confirming the furnace switch and breaker are on, keeping supply registers and return grilles open, and clearing snow, ice, or debris from outdoor vent and intake terminations. Never bypass, jumper, or reset safety switches (limit, flame-rollout, or pressure switches), never open the gas valve or burner compartment, and never attempt combustion, electrical, or control-board repairs yourself. Error codes point toward a problem but are not a substitute for proper diagnosis — when in doubt, turn the system off and call a licensed HVAC technician. Keep working carbon-monoxide detectors on every level of your home.
When to call a pro: Requires a licensed HVAC technician before the furnace runs again — rollout and heat-exchanger faults carry fire and carbon-monoxide risk. Never bypass or replace the rollout switch yourself. If a CO alarm sounds or you feel headache/nausea/dizziness, or you smell gas, leave immediately and call 911 or the gas utility from outside.
Lennox furnace code e200 FAQ
What does Lennox furnace code e200 mean?
Rollout circuit open — a hard lockout indicating the flame-rollout safety opened (flame or heat escaped the burner box). The furnace locks out for safety and should not be run until inspected.
What causes Lennox furnace code e200?
Common causes: Blocked heat exchanger or restricted/blocked venting; A cracked or failed heat exchanger; Dirty burners or poor combustion; Inducer failure.
Can I fix Lennox furnace code e200 myself?
You can safely try: Set the thermostat to OFF and leave the furnace off; Do NOT keep cycling power to force it to run; Record the code and call a professional — this is not a homeowner-serviceable fault. Requires a licensed HVAC technician before the furnace runs again — rollout and heat-exchanger faults carry fire and carbon-monoxide risk. Never bypass or replace the rollout switch yourself. If a CO alarm sounds or you feel headache/nausea/dizziness, or you smell gas, leave immediately and call 911 or the gas utility from outside.