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Rinnai RSC199i Error Codes

Updated · by Aurora Star Tech Inc.

Rinnai RSC199i error codes and diagnostic codes (also listed as REU-NP3237FF-US(A)). The RSC199i is a Rinnai tankless water heater in the SENSEI series.

Homeowner with a tankless water heater problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Rinnai RSC199i error codes list

CodeMeaningSeverity
03Power interrupted during bath fillLow
05Bypass flow control device faultMedium
10Air supply or exhaust blocked / condensate trap fullCritical
11No ignitionHigh
12Flame failureHigh
14Thermal fuse or overheat sensor trippedCritical
15Venturi control faultHigh
16Outlet water over-temperature safety shutdownCritical
17Venturi blockageHigh
19Electrical grounding / DC circuit shortHigh
21PC board data transfer errorHigh
25Condensate pump failure or clogged drainMedium
32Outlet water temperature thermistor faultMedium
33Heat exchanger thermistor faultMedium
38Exhaust gas temperature sensor (CO sensor on RH180)Critical
41Freeze protection / outdoor air temperature sensor faultMedium
51Inlet water temperature thermistor faultMedium
52Gas valve / modulating solenoid valve (POV) signal faultHigh
54High exhaust gas temperatureCritical
61Combustion fan motor faultHigh
63Recirculation low flowMedium
65Water flow control device (servo) faultMedium
70PC board faultHigh
71Gas solenoid valve fault (SV0–SV4 on Non-SENSEI)High
72Flame rod faultHigh
FFMaintenance performed (history marker)Low
SECascade diagnostic display (error on secondary unit)Medium
SSService Soon alert (also listed as 55)Low

Troubleshooting the RSC199i

Rinnai RSC199i specs and setup data

All Rinnai Tankless Water Heater error codes →

Homeowner help: Tankless Water Heater No Hot Water: What to Check

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

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