Water heater
Rheem water heater error codes
Every Rheem water heater code in our database, with plain-English meanings, likely causes, and what to try before calling for service. Codes can vary by model and year — always confirm against the legend on your unit or its manual.
- Code 11 Ignition failure (tankless)
- Code 12 Flame loss (tankless)
- Code 29 Condensate neutralizer fault
- Code 61 Fan motor / venting fault
- Status light: 2 flashes Low thermopile voltage / pilot not sensed
- Status light: 4 flashes High temperature limit switch open (tank) safety
- Status light: 3 flashes Water temperature not rising / sensor fault
- Code 16 Outlet water temperature sensor fault
- Code 21 Air intake filter door switch fault
- Code 24 Flow sensor fault
- Code 31 Inlet water filter problem
- Code 32 Heat exchanger problem
- Code 33 Combustion air supply problem
- Code 35 Fan motor problem
- Code 51 Gas valve problem
- Code 52 Modulating gas valve problem