Rinnai Error Codes

Find troubleshooting guides for all Rinnai error codes.

16 error codes across 1 appliance types

Waterheater

Code	Meaning	Severity
10	The unit detected that no gas was available or the gas valve was unable to open when a heating demand was made. high	high
11	The unit attempted to ignite 3 times and no flame was detected by the flame rod. The burner has locked out as a safety measure. high	high
12	The burner successfully ignited but the flame extinguished unexpectedly during a heating cycle. The unit shut down to prevent unsafe operation. high	high
14	The one-time thermal fuse (thermal cutoff) protecting the heat exchanger has blown, indicating the exchanger reached a dangerously high temperature. The unit is locked out until the fuse is replaced. critical	critical
15	The burner has been locked out following an abnormal combustion sequence during ignition. The unit detected an irregularity during the ignition attempt and shut down as a safety measure. high	high
17	The gas valve was unable to modulate or operate correctly as commanded by the control board. An abnormal voltage or position was detected during the heating cycle. high	high
25	The bath fill sequence did not complete within the programmed time limit. This code only appears on Rinnai models equipped with the built-in bath fill or ThermaCirc recirculation feature. low	low
32	The outlet water temperature sensor detected that the water leaving the heat exchanger exceeded the maximum safe limit. The unit shut down to prevent scalding or heat exchanger damage. high	high
52	The modulating gas valve was unable to reach or hold the target firing position commanded by the PCB. The valve's modulation mechanism has failed to operate correctly. high	high
55	The unit detected combustion that is outside normal operating parameters. This can mean incomplete combustion, combustion instability, or an air-to-fuel ratio that the sensors have flagged as abnormal. high	high
61	The combustion fan motor has failed to start or stopped operating completely. The unit cannot initiate or sustain a heating cycle without a functioning blower. high	high
63	The combustion fan (blower) did not reach the required speed within the expected time, or the fan speed sensor reported an abnormal reading during startup or operation. high	high
79	The sensor measuring the temperature of combustion air entering the unit has failed or is reading outside its expected range. moderate	moderate
HUB	Reference hub covering all Rinnai RU and V series tankless water heater error codes with diagnosis and repair guidance. low	low
NO-HOT-WATER	Error Code, Flow, and Flame Fixes medium	medium
RESET	Step-by-step instructions for performing soft, hard, and factory resets on Rinnai tankless water heaters to clear error codes and restore normal operation. low	low