Rinnai R75LSe Error Codes

Updated October 13, 2026 · by Aurora Star Tech Inc.

Rinnai R75LSe error codes and diagnostic codes (also listed as REU-VA2528WD(A)-UC). The R75LSe is a Rinnai tankless water heater in the Non-SENSEI series.

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Rinnai R75LSe error codes list

Code	Meaning	Severity
02	Burner did not operate during freeze protection	High
03	Power interrupted during bath fill	Low
05	Bypass flow control device fault	Medium
10	Air supply or exhaust blocked / condensate trap full	Critical
11	No ignition	High
12	Flame failure	High
14	Thermal fuse or overheat sensor tripped	Critical
16	Outlet water over-temperature safety shutdown	Critical
19	Electrical grounding / DC circuit short	High
25	Condensate pump failure or clogged drain	Medium
31	Burner thermocouple out of range	High
32	Outlet water temperature thermistor fault	Medium
33	Heat exchanger thermistor fault	Medium
34	Combustion air thermistor (Non-SENSEI) / Lime detecting thermistor (RX/CX)	Medium
38	Exhaust gas temperature sensor (CO sensor on RH180)	Critical
41	Freeze protection / outdoor air temperature sensor fault	Medium
51	Inlet water temperature thermistor fault	Medium
52	Gas valve / modulating solenoid valve (POV) signal fault	High
54	High exhaust gas temperature	Critical
57	Burner overheat bi-metal switch open	Critical
58	Secondary heat exchanger bi-metal switch open	High
61	Combustion fan motor fault	High
63	Recirculation low flow	Medium
65	Water flow control device (servo) fault	Medium
70	PC board fault	High
71	Gas solenoid valve fault (SV0–SV4 on Non-SENSEI)	High
72	Flame rod fault	High
73	Burner thermocouple fault	High
79	Water leakage detected	High
FF	Maintenance performed (history marker)	Low
LC	Scale build-up in heat exchanger (LC, LC0–LC9, 00)	Medium

Troubleshooting the R75LSe

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Rinnai R75LSe specs and setup data

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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.

Rinnai R75LSe error codes list

Troubleshooting the R75LSe

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