RHEEM ERROR CODE • CRITICAL SAFETY ALERT
Rheem Error Code E4: Flame Rollout Switch Open
This is a serious safety alert. Flames are escaping the combustion chamber. Do not operate your furnace until professionally inspected.
Critical Safety Warning
Rheem error code E4 indicates flames are escaping your furnace's combustion chamber. This creates fire and carbon monoxide poisoning risks. Stop using the furnace immediately and call for professional service.
If you smell gas or your carbon monoxide detector alarms, evacuate immediately and call 911.
What is Rheem Error Code E4?
E4 means the Flame Rollout Switch has opened. This safety device is positioned near the burners to detect if flames "roll out" of the combustion chamber where they belong. When triggered, it immediately shuts down gas flow.
Normal furnace operation keeps flames contained within the heat exchanger tubes. When flames escape—called "rollout"—it can ignite nearby components, damage the furnace, and release carbon monoxide into your home.
Unlike high limit faults (E1) which usually resolve with filter changes, E4 indicates a potentially dangerous mechanical or structural problem that requires professional diagnosis.
Common Causes of E4
Blocked Flue or Exhaust
Bird nests, debris, ice, or disconnected sections prevent combustion gases from exiting, causing pressure buildup and flame rollout. Check outdoor flue termination for obstructions.
Cracked Heat Exchanger
Cracks in the heat exchanger allow combustion gases and flames to escape. This is the most serious cause and typically requires furnace replacement. Professional camera inspection can confirm.
Insufficient Combustion Air
Furnaces need adequate air for proper combustion. Sealed mechanical rooms, blocked air intakes, or negative house pressure can starve the burners, causing improper flame patterns.
Clogged Burners
Rust, spider webs, or debris in burner ports create uneven flame patterns that can roll out of the combustion chamber.
What to Do
- 1Stop using the furnace - Do not attempt to reset and continue operating
- 2Check for gas smell - If present, evacuate and call gas company
- 3Check CO detectors - If alarming, evacuate and call 911
- 4Visually check outdoor flue - Look for obvious blockages (birds nests, ice)
- 5Call for professional service - E4 requires trained diagnosis
Frequently Asked Questions
What is Rheem error code E4?
Rheem error code E4 indicates the Flame Rollout Switch is open. This critical safety device has detected flames escaping the combustion chamber—a dangerous condition that can indicate a cracked heat exchanger, blocked flue, or improper combustion.
Is Rheem error code E4 dangerous?
Yes, E4 is a serious safety alert. Flame rollout can cause fires and indicates potential carbon monoxide risks. If E4 appears, do not continue operating the furnace until professionally inspected.
What causes flame rollout in Rheem furnaces?
Common causes include blocked flue or vent pipes, cracked heat exchanger, insufficient combustion air, clogged burners, or improper gas pressure. Each requires professional diagnosis.
Can I reset Rheem error code E4?
Rollout switches may have a manual reset button. However, resetting without addressing the cause is dangerous. If the switch trips again, there's a serious underlying problem. Call a professional before resetting.
Where is the rollout switch on a Rheem furnace?
Rollout switches are located near the burners, typically on the burner box or along the edge of the combustion chamber. Most Rheem furnaces have 2-3 rollout switches.
Can a dirty filter cause E4?
While dirty filters cause E1 (overheating), severe airflow restriction can affect combustion and contribute to rollout conditions. However, E4 typically indicates more serious issues beyond simple filter problems.
What's the difference between E1 and E4?
E1 is high limit (overheating from airflow issues). E4 is rollout (flames escaping combustion chamber). E1 is usually an airflow problem; E4 indicates dangerous combustion issues requiring immediate professional attention.
Can a blocked flue cause E4?
Yes, a blocked flue is a common cause. Bird nests, debris, ice, or disconnected flue sections prevent combustion gases from exiting, causing flames to roll out. Inspect the flue for blockages.
What if I smell gas with E4?
If you smell gas, leave immediately and call your gas company from outside. Do not operate switches or appliances. Gas smell combined with E4 indicates a serious and dangerous condition.
How long does it take to diagnose E4?
A thorough E4 diagnosis typically takes 45-90 minutes. The technician must inspect the heat exchanger, flue system, and combustion chamber to identify the root cause. Complex issues may require camera inspection.
Can a cracked heat exchanger cause E4?
Yes, a cracked heat exchanger is one of the most serious causes of E4. Cracks allow combustion gases to escape, triggering rollout switches. If suspected, do not operate the furnace—carbon monoxide poisoning is a risk.
Why does E4 happen after furnace sits unused?
After extended non-use, spider webs or debris may block burners or flue passages. Rust or corrosion may develop in the heat exchanger. Fall maintenance before heating season prevents these issues.
Can I continue using my furnace with E4?
No. Do not operate a furnace with E4 until professionally inspected. The error indicates potential fire and carbon monoxide hazards that require immediate attention.
Should I have a CO detector near my furnace?
Yes, carbon monoxide detectors are essential near all fuel-burning appliances. If E4 appears and your CO detector alarms, evacuate immediately and call 911.
Who repairs Rheem furnaces with E4 in the tri-state area?
Dimatic Control LLC provides expert Rheem furnace service including E4 diagnosis. Our technicians carry camera equipment for heat exchanger inspection. Call (908) 249-9701 for same-day emergency service.
E4 Requires Professional Service
Don't risk your family's safety. Our technicians are available 24/7 for E4 emergencies with same-day service.
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