Rheem R802VA07542117MSA Error Code A033_F: Roll-Out Switch Alarm
What Does Code A033_F Mean?
Fault code A033_F on the Rheem R802VA indicates that the flame roll-out safety switch has tripped. This is one of the most serious fault codes your furnace can display. Flame rollout means that flames are escaping from the combustion chamber in a direction they should not — typically out the front or sides of the burner compartment.
The roll-out switch is a temperature-sensitive safety device mounted near the burner openings. When it detects excessive heat outside the normal flame path, it trips open and immediately shuts down the furnace. This protects against fire hazards and carbon monoxide exposure.
The most common causes are a blocked heat exchanger or obstructed exhaust vent that prevents combustion gases from flowing through their normal path. A cracked heat exchanger can also allow combustion gases to escape improperly. A blocked exhaust vent outside the home (from ice, animal nests, or debris) is the one cause a homeowner can safely check.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Blocked or obstructed heat exchanger | Most common | ✗ Call a pro → |
| Cracked heat exchanger | Common | ✗ Call a pro → |
| Blocked exhaust vent causing backdraft | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Always call a professional for this fault code — flame rollout is a serious safety issue
- You see scorch marks or discoloration around the burner compartment
- You smell a burning odor near the furnace
- The roll-out switch keeps tripping after being reset
- The exhaust vent appears clear but the code persists
Sources
✓ Verified against manufacturer service manual — March 2026