Rheem tankless units display a numeric error code when combustion, water flow, or an internal sensor reports a fault. Code 11 (ignition) and 12 (flame failure) mirror the same pattern seen on Rinnai and Navien units; code 29 is specific to the condensate system.
Codes at a Glance
| Code | Meaning | |
|---|---|---|
| 11 | No ignition (same pattern as other brands) | Guide coming soon |
| 12 | Flame failure during operation | Guide coming soon |
| 29 | Condensate / neutralizer fault | Full guide → |
FAQ
Does Rheem use the same error codes as Rinnai or Navien?
The numbering isn’t identical across brands, but the underlying fault categories — ignition, flame loss, condensate, airflow — follow the same logic industry-wide.
Written by HotWater Decoded — water heater repair specialists. Technically reviewed by a licensed technician on our team.
Sources
- Rheem manufacturer documentation and JustAnswer threads
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