Rinnai Error Codes and Troubleshooting Tips

Rinnai is a popular brand of tankless water heaters that provides efficient and reliable heating solutions for homes and businesses. However, like any other electronic device, Rinnai tankless water heaters can also encounter issues or errors.

Here are some of the common Rinnai error codes and their solutions:

As always consult with your Certified Rinnai Installer before Troubleshooting

• Code 10 - This error code indicates a combustion failure, which means that the burner is not igniting properly. The possible causes for this error code include insufficient gas supply, blocked combustion air inlet or exhaust vent, or a damaged igniter. Ensure Rinnai approved venting materials are being used. Check that nothing is blocking the flue inlet or exhaust. Check all vent components for proper connections. Ensure vent length is within limits. Ensure condensation collar was installed correctly. Verify dip switches are set properly. Check fan for blockage. Replace the igniter if it is damaged.

Indoor models only

• Code 11 - This error code indicates a problem with the ignition system. The possible causes include a dirty or clogged burner, a faulty ignition electrode, or a malfunctioning gas valve. Check that the gas is turned on at the water heater, gas meter, or cylinder. Ensure gas type and pressure is correct.  Ensure gas line, meter, and/or regulator is sized properly.  Bleed all air from gas lines.  Verify dip switches are set properly.  Ensure appliance is properly grounded. Ensure igniter is operational. Check igniter wiring harness for damage. Check gas solenoid valves for open or short circuits. Remove burner cover and ensure all burners are properly seated. Remove burner plate and inspect burner surface for condensation or debris. Replace the gas valve if needed

• Code 12 - This error code indicates a flame failure, which means that the burner is not staying lit. The possible causes for this error code include a dirty or clogged burner, a faulty flame sensor, or a damaged thermocouple. Check that the gas is turned on at the water heater and gas meter. Check for obstructions in the flue outlet. Ensure gas line, meter, and/or regulator is sized properly. Ensure gas type and pressure is correct. Bleed all air from gas lines. Ensure proper Rinnai venting material was installed. Ensure condensation collar was installed properly. Ensure vent length is within limits. Verify dip switches are set properly. Ensure appliance is properly grounded. Disconnect keypad. Disconnect EZConnect or MSA controls to isolate the problem. Check power supply for loose connections. Check power supply for proper voltage and voltage drops. Ensure flame rod wire is connected. Check flame rod for carbon build-up. Disconnect and re-connect all wiring harnesses on unit and PC board. Check all components for electrical short. Check gas solenoid valves for open or short circuits. Remove burner plate and inspect burner surface for. Replace the flame sensor, or replace the thermocouple if it is damaged.

• Code 14 - This error code indicates a problem with the thermal fuse, which is a safety device that prevents the heater from overheating. The possible causes for this error code include a dirty air filter, a blocked exhaust vent, or a malfunctioning thermal fuse. Check gas type of unit and ensure it matches gas type being used. Check for restrictions in air flow around unit and vent terminal. Check for low water flow in a circulating system causing shortcycling. Ensure dip switches are set to the proper position. Check for foreign materials in combustion chamber and/or exhaust piping. Check heat exchanger for cracks and/or separations. Check heat exchanger surface for hot spots which indicate blockage due to scale build up. Refer to instructions in manual for flushing heat exchanger. Measure resistance of safety circuit. Ensure high fire and low fire manifold pressure is correct. Check for improper conversion of product. The solution is to clean the air filter and exhaust vent, and if that doesn't work, replace the thermal fuse.

•  Code 16 - This error code indicates a problem with the exhaust thermistor, which is a device that measures the temperature of the exhaust gases. The possible causes for this error code include a damaged thermistor, a loose connection, or a faulty control board. The solution is to replace the thermistor, check for loose connections, or replace the control board if it is faulty.
• Code 16 (on older models) Over Temperature Warning Check for restrictions in air flow around unit and vent terminal. Check for low water flow in a circulating system causing shortcycling. Check for foreign materials in combustion chamber and/or exhaust piping. Check for clogged heat exchanger.

It's always recommended to consult with a qualified technician if you're experiencing any issues with your Rinnai tankless water heater, as they have the expertise to diagnose and fix the problem safely and effectively.

• Code 25 - This error code indicates an issue with the inlet thermistor, which is a device that measures the temperature of the incoming water. The possible causes for this error code include a damaged thermistor, a loose connection, or a faulty control board. The solution is to replace the thermistor, check for loose connections, or replace the control board if it is faulty.

• Code 29 - This error code indicates a problem with the outlet thermistor, which is a device that measures the temperature of the outgoing water. The possible causes for this error code include a damaged thermistor, a loose connection, or a faulty control board. The solution is to replace the thermistor, check for loose connections, or replace the control board if it is faulty.

• Code 61 - This error code indicates a problem with the fan, which is responsible for venting the exhaust gases outside. The possible causes for this error code include a dirty fan, a malfunctioning fan motor, or a blocked vent. The solution is to clean the fan, replace the fan motor if it is faulty, or remove any blockages in the vent.

• Code 79 - This error code indicates a communication error between the heater and the remote control. The possible causes for this error code include a faulty remote control, a loose connection, or a malfunctioning control board. The solution is to check the remote control and its connections, and replace it if necessary. If the problem persists, the control board may need to be replaced as well.

• No Code (Nothing happens when water flow is activated.) Clean inlet water supply filter. On new installations ensure hot and cold water lines are not reversed. Check for bleed over. Isolate unit from building by turning off hot water line to building. Isolate the circulating system if present. Open your pressure relief valve; if unit fires, there is bleed over in your plumbing. Ensure you have at least the minimum flow rate required to fire unit. Ensure turbine spins freely. Measure the resistance of the water flow control sensor. Remote control does not light up but you have 12 VDC at the terminals for controls

In summary, Rinnai tankless water heaters can display various error codes that indicate different issues. If you experience any of these error codes, it's best to consult with a qualified technician to diagnose and fix the problem. Regular maintenance and cleaning can also help prevent these errors and keep your Rinnai tankless water heater running smoothly.

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