Lennox SLP98UHV Error Code E 200: Hard Lockout - Rollout Circuit Open

What Does Code E 200 Mean?

Error code E 200 on the Lennox SLP98UHV indicates a hard lockout caused by the rollout circuit being open or having been open previously. The flame rollout switch is a critical safety device mounted near the burners that trips when it senses excessive heat outside the combustion chamber — the signature of flames rolling out of where they should be contained. Because the SLP98UHV is a sealed, high-efficiency modulating furnace, its combustion and venting are engineered to keep every flame inside the heat exchanger, so a rollout trip signals that something has gone seriously wrong with either the heat exchanger or the venting path.

Flame rollout is one of the most dangerous conditions a gas furnace can experience. It is most often caused by a blocked or cracked heat exchanger, or by a restricted flue or exhaust that forces combustion gases and flame backward out of the burner area. On this SureLight-controlled furnace, that same escaping combustion also stresses the pressure-switch and inducer circuit, so an E 200 can appear alongside venting-related faults. Any of these conditions can push carbon monoxide into your home or create a fire hazard.

Unlike the soft lockouts on this board (such as E 270 or E 273, which clear on their own after a successful cycle), a hard lockout latches and will not clear until the root cause is corrected. Even if the rollout switch itself resets once the furnace cools, the underlying problem has not been fixed. The furnace should stay off until a qualified HVAC technician has inspected the heat exchanger, the full venting system, and the combustion air supply to determine why flame left the combustion chamber.

What You'll Notice

• The furnace is completely dead and will not restart after shutting down
• You noticed a rumble, a loud 'whoomph', or a bang shortly before the furnace quit
• A burning or hot-metal smell near the furnace
• Soot, scorch marks, or discoloration around the burner compartment or blower door
• No heat, and the 7-segment display shows E 200 when you recall the fault history

Common Causes

How This Is Diagnosed

A technician treats E 200 as a combustion-containment failure, not a nuisance trip. They first inspect the heat exchanger for cracks, holes, or blockage and check the flue and combustion-air piping for restriction, sagging, ice, or debris, since a blocked vent is the most common driver of rollout. They also verify the inducer is moving the correct volume of air and confirm the rollout switch and its wiring are intact.

Only after the root cause is found and corrected is the flame rollout switch reset or replaced and the furnace test-fired while combustion is observed. Carbon monoxide readings and draft are typically checked before the unit is returned to service.

When to Call a Professional

This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:

• Immediately — E 200 is a safety-critical rollout code that needs professional diagnosis before the furnace runs again
• You smell a burning odor, or see soot or scorch marks near the furnace
• The code returns immediately after the furnace is reset or after it cools down
• Do not attempt to reset or bypass the rollout switch yourself

✓ Verified against manufacturer service manual — March 2026