Goodman GMSS920803BN Error Code 6 Flashes: Rollout Limit Circuit Open / Control Board Fuse Blown

What Does Code 6 Flashes Mean?

Six flashes on the Goodman GMSS920803BN diagnostic LED indicate that the rollout limit circuit is open or the Integrated Control Module's fuse has blown. Flame rollout means combustion gases and flame are escaping the front of the burner box instead of being drawn back through the heat exchanger — a serious safety hazard that this switch exists to catch.

The rollout limit is a safety device mounted near the burners that opens when it senses excessive heat outside the combustion chamber. On this single-stage furnace the most common trigger is a blocked exhaust flue or intake air pipe, which starves the burners of proper draft and pushes flame forward toward the rollout sensor. Misaligned burners and a failed induced-draft blower can create the same rollout condition. The board's 3-amp fuse can also blow from a short in the 24-volt control or safety circuits, producing an identical 6-flash code, in which case the furnace will not operate at all.

This is the most safety-critical code on the board and should not be confused with the 4-flash limit code. Four flashes is an over-temperature trip driven by low airflow and often clears with a filter change, whereas six flashes means flame is physically escaping the combustion chamber or a safety-circuit fuse has failed. Replacing the fuse or resetting the rollout without finding the cause simply re-exposes the home to the original hazard.

What You'll Notice

• The furnace will not operate and the LED repeats a six-flash pattern
• You may notice soot marks, scorching, or heat discoloration on or around the burner box
• There may be a hot or burnt smell near the furnace
• If the board fuse has blown, the furnace is completely unresponsive to a heat call
• The exhaust or intake pipe termination outside may be blocked, iced, or obstructed

Common Causes

How This Is Diagnosed

Because rollout is safety-critical, a technician treats the venting and combustion path as the priority. They inspect the PVC flue and intake piping for blockage, incorrect length, or a bad termination, verify the induced-draft blower is moving the correct volume of air, and check the burners for proper alignment so flame is drawn back rather than pushed forward.

The rollout limit switch itself is tested for correct operation, and if the board fuse is blown, the 24-volt control and safety circuits are traced for the short that blew it before any replacement fuse is installed. Every part of this diagnosis involves the sealed combustion system, gas burners, and control wiring, so it is professional service work — not a homeowner reset.

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:

• The LED shows six flashes — stop using the furnace and have it inspected before further operation
• You see soot, scorching, or heat marks outside the combustion chamber
• The control-module fuse is blown, or it blows again after replacement
• The exhaust or intake pipe is blocked and you cannot safely clear it
• The rollout code returns after any reset

✓ Verified against manufacturer service manual — March 2026