Rheem Error Code Reference — All 21 Codes
Complete Rheem error code cheat sheet. All 21 fault codes with plain-English explanations and direct links to fix guides.
Use this page when your Rheem furnace, air conditioner, heat pump, or mini split is flashing a fault. Start with the exact code, then open the fix guide to diagnose airflow, ignition, sensor, pressure switch, board, or communication problems before you order parts or book a service call.
Tip: search the exact brand, model, and code together, for example "Rheem error code 13" or "Rheem pressure switch fault".