Rinnai tankless water heaters are known for their energy efficiency and long-lasting
performance. However, like any appliance, they can experience issues from time to time. If you
own a Rinnai tankless water heater, it's important to be aware of the various error codes that
may appear on the display screen.
Here's a comprehensive list of Rinnai error codes and what they mean:
1. Rinnai Error Code 00 - This error code indicates a communication problem between the
remote control and the water heater. Check the remote control wiring connections and replace
any faulty components as necessary.
2. Rinnai Error Code 01 - This error code indicates a problem with the ignition or flame
detection system. Check the gas supply, gas pressure, and the ignition and flame sensors, and
clean or replace them as necessary.
3. Rinnai Error Code 02 - This error code indicates a problem with the combustion chamber
temperature sensor. Check the sensor and wiring connections, and replace or repair them as
necessary.
4. Rinnai Error Code 03 - This error code indicates a problem with the ignition or flame
detection system. Check the gas supply, gas pressure, and the ignition and flame sensors, and
clean or replace them as necessary.
5. Rinnai Error Code 05 - This error code indicates a problem with the combustion air sensor.
Check the sensor and wiring connections, and replace or repair them as necessary.
6. Rinnai Error Code 06 - This error code indicates a problem with the exhaust temperature
sensor. Check the sensor and wiring connections, and replace or repair them as necessary.
7. Rinnai Error Code 07 - This error code indicates a problem with the heat exchanger
temperature sensor. Check the sensor and wiring connections, and replace or repair them as
necessary.
8. Rinnai Error Code 10 - This error code indicates a problem with the combustion chamber
temperature sensor. Check the sensor and wiring connections, and replace or repair them as
necessary.
9. Rinnai Error Code 11 - This error code indicates a problem with the gas supply or gas
pressure. Check the gas supply and gas pressure, and repair or replace any faulty components
as necessary.
10. Rinnai Error Code 12 - This error code indicates a problem with the flame failure or
improper flame detection. Check the ignition and flame sensors, and clean or replace them as
necessary.
11. Rinnai Error Code 14 - This error code indicates a problem with the thermal fuse or
overheating. Check the thermal fuse, ventilation system, and heat exchanger, and clean or
replace them as necessary.
12. Rinnai Error Code 16 - This error code indicates a problem with the temperature controller
or wiring connections. Check the controller and wiring connections, and replace or repair them
as necessary.
13. Rinnai Error Code 18 - This error code indicates a problem with the water flow rate. Check
the water flow rate and pressure, and repair or replace any faulty components as necessary.
14. Rinnai Error Code 19 - This error code indicates a problem with the high limit switch or
overheating. Check the ventilation system, heat exchanger, and high limit switch, and clean or
replace them as necessary.
15. Rinnai Error Code 25 - This error code indicates a problem with the inlet thermistor or
wiring connections. Check the thermistor and wiring connections, and replace or repair them as
necessary.
16. Rinnai Error Code 31 - This error code indicates a problem with the inlet water supply or
pressure. Check the water supply and pressure, and repair or replace any faulty components as
necessary.
17. Rinnai Error Code 32 - This error code indicates a problem with the outlet water
temperature sensor or wiring connections. Check the sensor and wiring connections, and
replace or repair them as necessary.
18. Rinnai Error Code 33 - This error code indicates a problem with the heat exchanger or
overheating. Check the heat exchanger and ventilation system, and clean or replace them as
necessary.
19. Rinnai Error Code 34 - This error code indicates a problem with the combustion air
pressure sensor. Check the sensor and wiring connections, and replace or repair them as
necessary.
20. Rinnai Error Code 51 - This error code indicates a problem with the mixing valve or mixing
valve wiring connections. Check the valve and wiring connections, and replace or repair them
as necessary.
21. Rinnai Error Code 52 - This error code indicates a problem with the outlet thermistor or
wiring connections. Check the thermistor and wiring connections, and replace or repair them as
necessary.
22. Rinnai Error Code 61 - This error code indicates a problem with the fan or fan wiring
connections. Check the fan and wiring connections, and replace or repair them as necessary.
23. Rinnai Error Code 63 - This error code indicates a problem with the electronic control
board or wiring connections. Check the control board and wiring connections, and replace or
repair them as necessary.
24. Rinnai Error Code 65 - This error code indicates a problem with the water flow sensor or
wiring connections. Check the sensor and wiring connections, and replace or repair them as
necessary.
25. Rinnai Error Code 71 - This error code indicates a problem with the gas valve or wiring
connections. Check the valve and wiring connections, and replace or repair them as necessary.
26. Rinnai Error Code 72 - This error code indicates a problem with the bypass servo or wiring
connections. Check the servo and wiring connections, and replace or repair them as necessary.
27. Rinnai Error Code 73 - This error code indicates a problem with the modulating valve or
wiring connections. Check the valve and wiring connections, and replace or repair them as
necessary.
28. Rinnai Error Code 74 - This error code indicates a problem with the mixing valve or mixing
valve wiring connections. Check the valve and wiring connections, and replace or repair them
as necessary.
29. Rinnai Error Code 75 - This error code indicates a problem with the mixing valve or mixing
valve wiring connections. Check the valve and wiring connections, and replace or repair them
as necessary.
30. Rinnai Error Code 76 - This error code indicates a problem with the combustion air
pressure sensor or wiring connections. Check the sensor and wiring connections, and replace
or repair them as necessary.
By understanding these error codes and their meanings, you can troubleshoot and repair your
Rinnai tankless water heater quickly and effectively. It's important to note that attempting to
diagnose or repair your Rinnai tankless water heater on your own can be dangerous and can
potentially cause further damage to the unit. It's recommended to contact a professional Water
Heater Technician if you encounter any error codes or issues with your water heater. With
regular maintenance and timely repairs, your Rinnai tankless water heater can provide years of
reliable, energy-efficient service for your home or business.
The Water Heater Company is a small family-owned and operated business. If you are in our
service area and need assistance with your tankless water heater, give us a call. We look
forward to helping you with your water heater repair and maintenance needs.
