In this article, we’ll explore every error code from Rinnai’s tankless water heaters that you may encounter, along with quick bullet points for the troubleshooting steps you can take to resolve them. For some of these error codes, you are going to need the help of a pro but many of them have easy solutions that you can handle on your own. All this information can be found in manuals and tech sheets but let’s be honest no one wants to dig through 2-5 tech sheets and manuals to find all the details you need. Don’t worry, we have you covered.
Rinnai produces high-quality tankless water heaters; arguably the most reliable we know well. Just like any household appliance, if you give them enough time, errors, or malfunctions something is going to happen, the thing is going to break on you. But, that is how you found us I am sure and we can give you a clear explanation of each Rinnai error code and how to troubleshoot them. This is basic but valuable information that we hope is going to save both time and money.
| Error Code | Description |
| 02 | No burner operation during freeze protection |
| 03 | Power interruption during Bath fill |
| 10 | Air Supply or Exhaust Blockage |
| 11 | No Ignition |
| 12 | Flame Failure |
| 14 | Thermal Fuse |
| 16 | Over Temperature Warning |
| 31 | Burner Sensor Error |
| 32 | Outgoing Water Temperature Sensor Fault |
| 33 | Heat Exchanger Outgoing Temperature Sensor Fault |
| 34 | Combustion Air Temperature Sensor Fault |
| 52 | Modulating Solenoid Valve Signal Abnormal |
| 61 | Combustion Fan Failure |
| 65 | Water Flow Servo Faulty |
| 71 | Solenoid Valve Circuit Fault |
| 72 | Flame Sensing Device Fault |
Error Code 02: No burner operation during freeze protection mode
- Service Call
Error Code 03: Power interruption during Bath fill (Water will not flow when power returns)
- Turn off all hot water taps. Press ON/OFF twice.
Error Code 10: Air Supply or Exhaust Blockage
For detailed breakdown of these steps and diagrams see Rinnai error code 10
- 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.
Error Code 11: No Ignition
For in-depth instructions see this article: Rinnai error code 11
- 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.
- Disconnect EZConnect or MSA controls to isolate the problem.
- 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.
Error Code 12: Flame Failure
- 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 condensation or debris.
- Check the ground wire for the PC Board.
For more detailed step by step instructions see Rinnai Error Code 12.
Error Code 14: 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 this article for instructions on how to flush a rinnai tankless water heater.
- Measure resistance of safety circuit.
- Ensure high fire and low fire manifold pressure is correct.
- Check for improper conversion of product.
For more detailed troubleshooting and fixes see Rinnai Error Code 14
Error Code 16: 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.
In-depth instructions to resolve: Rinnai Error Code 16
Error Code 31: Burner Sensor Error
- Measure resistance of sensor.
- Replace sensor.
Error Code 32: Outgoing Water Temperature Sensor Fault
- Check sensor wiring for damage.
- Measure resistance of sensor.
- Clean sensor of scale build up.
- Replace sensor.
Error Code 33: Heat Exchanger Outgoing Temperature Sensor Fault
- Check sensor wiring for damage.
- Measure resistance of sensor.
- Clean sensor of scale build up.
- Replace sensor.
Error Code 34: Combustion Air Temperature Sensor Fault
- Check for restrictions in air flow around unit and vent terminal.
- Check sensor wiring for damage.
- Measure resistance of sensor.
- Clean sensor of scale build up.
- Ensure fan blade is tight on motor shaft and is in good condition.
- Replace sensor.
More detailed troubleshooting of Rinnai Error Code 34
Error Code 52: Modulating Solenoid Valve Signal Abnormal
- Check modulating gas solenoid valve wiring harness for loose or damage terminals.
- Measure resistance of valve coil.
Error Code 61: Combustion Fan Failure
- Ensure fan will turn freely.
- Check wiring harness to motor for damaged and/or loose connections.
- Measure resistance of motor winding.
In-Depth on Rinnai Error Code 61
Error Code 65: Water Flow Servo Faulty (does not stop flow properly)
- If blank screen is present on remote control then the flow control has shorted out. Unplug flow control. If remote lights up and unit starts operating then replace flow control assembly.
Error Code 71: Solenoid Valve Circuit Fault
- Replace the PC Board.
Error Code 72: Flame Sensing Device Fault
- Ensure flame rod is touching flame when unit fires.
- Check all wiring to flame rod for damage.
- Remove flame rod and check for carbon build-up; clean with sand paper.
- Check inside burner chamber for any foreign material blocking flame at flame rod.
- Measure micro amp output of sensor circuit with flame present.
- Replace flame rod.
Error Code 73: Burner Sensor Circuit Error
- Check sensor wiring and PCB for damage.
- Replace sensor
Error Code LC or 00: Scale Build-up in Heat Exchanger
- Flush heat exchanger. Refer to: how to descale a Rinnai tankless water heater.
- Replace heat exchanger.
No code, but nothing happens when water flow is activated.
Sometimes your issue is you have no hot water but also no error code. If you have this issue and the steps below don’t work this article is more in-depth Rinnai Tankless Water Heater No Hot Water
- 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.
I hope this article has been able help troubleshoot your Rinnai tankless water heater error codes and help save you some money on a service call. Some errors require professional assistance, but many of them can be resolved with basic troubleshooting steps like checking the gas supply, inspecting the venting, or cleaning the sensors. If you encounter an error code that you can’t resolve, don’t hesitate to contact a qualified technician to assist you.
Sources:
Rinnai Tech/Troubleshooting PDF
Rinnai Installation and Opperation Manual PDF
Diagram From Commercial Operation Manual