Keep the furnace off. Do not reset a rollout switch. If you smell gas or a carbon-monoxide alarm sounds, leave the building and contact emergency services or the gas utility.
What does Rheem code 33 mean?
Rheem furnace code 33 means the manual-reset limit control circuit is open on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Rheem code 33?
- A blocked flue or combustion-air path
- A burner or gas-pressure problem
- A damaged or restricted heat exchanger
Can I troubleshoot Rheem code 33?
Keep the furnace off. Do not reset a rollout switch. If you smell gas or a carbon-monoxide alarm sounds, leave the building and contact emergency services or the gas utility.
How much does Rheem code 33 cost to fix?
A heat exchanger replacement typically costs between $500 and $3,500 nationally.
When should I call a technician?
Leave the furnace off and call a licensed technician for a combustion-safety inspection.
Sources and model scope
Fault codes vary by model and control board. Confirm the diagnostic chart inside your furnace panel or the official manual before acting.
Scope used here: Rheem/Ruud RGFG-family controls using the documented two-digit diagnostic table.
- Rheem Manufacturing Company: RGFG Series Gas Furnace Installation Instructions and Diagnostic Codes
92-24161-104-06 · Rheem/Ruud RGFG-family furnace controls; confirm the unit model and its door chart before applying a code meaning.
Compiled by Warmlo Editorial · Reviewed August 2026
This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.