Run capacitor
Common no-start and weak-compressor failure point. Match the microfarad and voltage rating.
Error Code: Goodman 6 Flashes
What it means: Six flashes on a Goodman furnace diagnostic LED indicates an open rollout switch. The rollout switch is a manual-reset thermal safety device mounted on the burner box. It opens when it detects flame escaping the burner compartment — a condition called flame rollout. Normal combustion stays contained within the heat exchanger; rollout means combustion gases are escaping backward into the furnace cabinet. The rollout switch will not reset by cycling power — it must be manually reset by pressing the red button on the switch body after the underlying cause is corrected.
Common Causes
- Cracked heat exchanger — The most serious cause. A crack allows the blower’s negative pressure to pull combustion gases back through the burner box. Requires immediate shutdown and professional inspection.
- Blocked primary or secondary heat exchanger — Scale, debris, or a partially blocked flue restricts the path for combustion gases. With nowhere to go, gases roll back out of the burners.
- Weak or failed inducer motor — If the inducer cannot maintain adequate draft, gases don’t flow properly through the exchanger and can escape through the burner openings.
- Insufficient combustion air — Furnaces in sealed utility rooms or closets without adequate combustion air openings can draw combustion gases backward when the air supply is exhausted.
- High gas pressure — Excess gas pressure creates a larger, more turbulent flame that overflows the burner ports.
Diagnosis Steps
- Do not reset the rollout switch immediately. First investigate the cause — resetting and restarting without diagnosis is a CO hazard.
- Inspect the burner compartment for soot deposits outside the normal burn zone. Soot marks on the burner box walls, draft diverter, or burner compartment panels confirm flame rollout occurred.
- Check the flue pipe for blockages. On 80% furnaces, inspect the metal flue and chimney connection. On 90%+ furnaces, check both PVC vent pipes for blockages, ice (exterior terminations in winter), or disconnected joints.
- Start the inducer manually and feel for draft at the burner opening before ignition. Strong inward pull is normal. Weak or no inward draft points to inducer or flue issues.
- After correcting any blockage or inducer issue, carefully inspect the heat exchanger via sight glass or inspection camera for cracks.
Fix
Clear any flue blockage or correct combustion air deficiency. If the inducer is running slowly, check the inducer motor run capacitor — a weak capacitor reduces RPM without fully failing the motor. Replace the capacitor if it measures outside rated MFD.
If heat exchanger damage is suspected, do not restart the furnace. A cracked Goodman heat exchanger requires replacement of the heat exchanger assembly or full furnace replacement, depending on age and availability.
Once the root cause is corrected, locate the rollout switch — typically a round snap-disc device with a red reset button, mounted on the burner bracket or side of the burner box. Press the reset button until you feel/hear a click. Restore power and run a test cycle.
Parts
| Part | Where to Buy |
|---|---|
| Rollout limit switch | RepairClinic, SupplyHouse |
| Inducer motor assembly | RepairClinic, Grainger |
| Inducer motor capacitor | Grainger |
Need Replacement Parts?
Before ordering, match the furnace part to the model number, electrical rating, and failure symptom. Check current prices on Amazon - prices and availability change frequently.
When to Call a Technician
Any Code 6 fault with suspected heat exchanger failure or CO risk requires a licensed HVAC technician immediately. Do not operate the furnace. Rollout faults caused by inducer or flue blockage are diagnosable by a competent DIYer, but gas pressure adjustments and heat exchanger testing require professional equipment.