Run capacitor
Common no-start and weak-compressor failure point. Match the microfarad and voltage rating.
Error Code: Rheem/Ruud 6 Flashes
What it means: Six flashes on a Rheem or Ruud furnace diagnostic LED indicates an open rollout switch. The rollout switch (rollout limit) is a manual-reset thermal safety device mounted at the burner assembly. It trips when flame escapes the burner box — a condition called flame rollout — which means combustion is occurring outside the designed combustion path. Rollout is a serious condition. Unlike the high limit, the rollout switch will not auto-reset — it must be manually reset after the cause is identified and corrected.
Common Causes
- Cracked or failed heat exchanger — The blower draws air through the heat exchanger under negative pressure. A crack allows this negative pressure to pull flame backward through the burner ports. Immediate shutdown required.
- Blocked flue or vent pipe — Restricted flue prevents combustion gases from exiting. Pressure builds in the heat exchanger and forces gases back through the burners.
- Failed inducer motor — Insufficient draft from a slow or failed inducer allows combustion gases to back up into the burner area.
- Incorrect gas pressure — Overpressure at the manifold creates an oversized flame that exceeds the burner port geometry and rolls out.
- Blocked secondary heat exchanger — On high-efficiency condensing furnaces, scale or debris in the secondary (condensing) section creates backpressure.
Diagnosis Steps
- Do not immediately reset the rollout switch. Investigate first.
- Open the furnace cabinet and inspect the burner compartment for soot deposits on the walls, draft diverter, or surrounding surfaces. Soot outside the heat exchanger confirms flame rollout.
- Manually start the inducer (using test mode if available) before ignition. Hold your hand near the burner area — you should feel a strong inward draft. Weak or reversed airflow points to inducer or flue issues.
- Inspect the vent system: metal flue or PVC pipes must be fully intact, connected, and unobstructed at all joints and terminations.
- If flue and inducer check out, the rollout is likely caused by a heat exchanger breach. Have a tech inspect with a combustion analyzer or inspection camera.
Fix
Clear any flue blockage and restore full combustion airflow. If the inducer motor is the cause (low RPM, won’t start), replace the inducer motor or its run capacitor.
Once the cause is corrected, locate the rollout switch on the burner bracket. It is a round, bi-metal snap-disc device with a small red or white reset button on top. Press firmly until you hear/feel a click. If the button depresses but springs back without clicking, the switch has failed and must be replaced — do not continue operating the furnace.
Restore power and observe a full heating cycle. Watch through the sight glass that flames stay contained within the burner ports.
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 rollout fault where heat exchanger damage is suspected requires a licensed HVAC technician immediately. Do not operate the furnace until cleared. Rollout is one of the few furnace faults that presents a direct CO and fire risk. If you can’t identify a clear, non-heat-exchanger cause, call a tech before resetting anything.