Rinnai tankless water heater error codes: Reasons and Fixes

Introduction

In this Article, our Chief Water heater Expert Joseph will explain Rinnai error codes you might encounter with your Rinnai tankless water heater and provide a perfect solution to troubleshooting them. Rinnai tankless water heaters are one of the best preferred choice for hot water supply for many homes in United states and Canada. These systems not only provide continuous hot water but also come equipped with advanced self-diagnostic tools that issue error codes to help identify and resolve issues quickly.

Rinnai heaters are renowned for their longevity, typically lasting over 20 years with proper maintenance. They are more energy-efficient than traditional tank heaters and occupy less space. The built-in self-diagnostic system aids significantly in maintenance by automatically detecting faults and displaying corresponding error codes.

Rinnai Error codes: Reasons and their Fixes

Error Code 02: No Burner Operation During Freeze Protection Mode

• Step 1: This code indicates a malfunction during a freeze protection attempt. Immediately call a qualified technician to handle gas and burner issues safely.

Error Code 03: Power Interruption During Bath Fill

• Step 1: Close all hot water taps to stop any water flow.
• Step 2: Reset the system by pressing the On/Off button twice.
• Step 3: Open the hot water taps again to see if the system resets successfully. If you see the error again repeat it for 3 times, if still no luck replace the PC board.

Error Code 10: Blocked Exhaust or Air Supply

Error Code 10 on a Rinnai tankless water heater indicates that the exhaust or air supply is blocked. Here’s a concise guide to help you troubleshoot this issue:

• Check Venting Material: Ensure all venting materials are Rinnai-approved. Non-approved materials can cause improper exhaust flow. Reference the Rinnai installation manual or their website for a list of approved materials.
• Inspect for Blockages: Examine the flue inlet and exhaust outlets for obstructions like bird nests or debris. Remove any blockages carefully to avoid damaging the venting.
• Verify Venting Component Connections: Check that all venting components are properly connected and secure. Tighten any loose connections to ensure proper exhaust flow.
• Examine the Condensation Collar: Check if the condensation collar is properly installed and secure. Adjust or reinstall if it is loose or improperly placed.
• Assess Dip Switch Settings: Confirm dip switches are correctly set for your installation. Adjust according to the user manual if settings are incorrect.
• Inspect the Fan: Ensure the fan is rotating properly without obstructions. Listen for unusual noises or check visually for debris.
• Monitor and Professional Help: After performing these steps, monitor the unit to see if the error clears. If Error Code 10 persists, contact a certified plumber or Rinnai technician for further assistance.

Error Code 11: Ignition Problems

Joseph already published a dedicated article on this please visit: Rinnai tankless water heater code 11 [easy guide to fix]

Error Code 12: Flame Failure

Joseph already published a dedicated article on this please visit: How to fix Rinnai Tankless Water Heater Code 12 [In Detail]

Error Code 14: Thermal Fuse

Error Code 14 typically relates to issues with the thermal fuse in Rinnai tankless water heaters. This error indicates potential problems with gas supply, airflow, water flow, or blockages. Follow these steps to troubleshoot:

• Check Gas Type: Confirm that the gas type (natural gas or propane) of the unit matches the gas type being used. Improper gas type can affect combustion and trigger this error.
• Inspect Air Flow: Ensure there are no restrictions in air flow around the unit and vent terminal. Remove any debris or obstructions to promote proper ventilation.
• Evaluate Water Flow: Check for low water flow in the circulating system which can cause short-cycling. Adjust the flow rate as necessary to ensure stable operation.
• Verify Dip Switch Settings: Ensure the dip switches on the unit are set correctly according to your specific model and installation requirements.
• Check Combustion Chamber and Exhaust: Inspect the combustion chamber and exhaust piping for any foreign materials or blockages that could impact performance.
• Inspect the Heat Exchanger: Examine the heat exchanger for any signs of cracks, separations, or hot spots which indicate blockages due to scale build-up. Follow the manufacturer’s instructions to flush the heat exchanger if blockages are present.
• Measure Safety Circuit Resistance: Use a multimeter to measure the resistance of the safety circuit to ensure it is within the specified range.
• Check Manifold Pressure: Verify that both high fire and low fire manifold pressures are correct. Adjustments may be required to ensure optimal operation.
• Verify proper gas venturi was installed in gas valve.
  – Red orifice = Propane (L.P.)
  – Blue orifice = Natural gas

Error Code 16: High Outgoing water temperature

When your Rinnai tankless water heater displays Error Code 16, indicating a high outgoing water temperature when it exceeds more than 203°F or 95°C, follow these steps to troubleshoot and resolve the issue:

• Check Air Flow Around Vent Terminal: Ensure no obstructions around the vent terminal that could restrict airflow, as this can affect temperature control.
• Inspect Fan Operation: Confirm the fan operates smoothly without odd noises, since a faulty fan can disrupt air-to-fuel ratio and increase temperature.
• Verify Check Valve: Ensure the check valve behind the fan motor isn’t stuck as this can limit airflow and impact combustion.
• Inspect Combustion Chamber and Exhaust Piping: Remove any foreign materials or buildup that might alter heater operation and increase temperature.
• Check Heat Exchanger: Look for blockages or scale buildup in the heat exchanger, as this can cause water to overheat.
• Verify Correct Gas Type: Confirm the heater is set for the correct gas type (Natural Gas or Propane) as per the rating plate. For SENSEI Series, ensure Parameter 10 matches the gas type (A for Natural Gas, B for Propane).
• Replace Gas Valve Assembly: If issues persist, consider replacing the gas valve assembly which could be improperly regulating gas flow.
• Replace Fan Motor Assembly: If the fan motor is defective, replace it to ensure proper ventilation and temperature control.

Code 17: Venturi Blockage

If your Rinnai tankless water heater displays Error Code 17, indicating a Venturi blockage, here are concise steps to resolve the issue:

• Check Condensate Drain Line: Ensure the condensate drain is clear and properly draining to prevent backflow issues.
• Inspect Vent System: Examine the entire vent system—intake air, exhaust chamber, and vent termination for any obstructions that could impede airflow.
• Inspect and Clean the Venturi: Remove the gas valve and Venturi assembly from the fan motor. Check for and remove any debris or blockage in the Venturi, which is essential for efficient air and gas mixing.
• Re-install Venturi Assembly: After cleaning, re-install the Venturi assembly.
• Reset the Heater: Reset the water heater to clear the error code and resume normal operation.

Code 19: Electrical grounding

If Error Code 19 appears right after water flow starts on your water heater, it indicates an electrical short in one of the components. This issue could stem from a variety of parts within the DC circuit, such as the wiring harness, water flow control, bypass valve, or another related component. To isolate the problem, methodically unplug each component one at a time and then attempt to cycle the water heater. If the system successfully completes three cycles without the error after a component is unplugged, the electrical short is associated with that specific component.

Code 25: Condensate pump error or drain is clogged

Error Code 25 on your water heater signals a problem related to the condensate pump or drain system. This code typically appears when the condensate safety switch is triggered due to backed up water activating the float switch. This can also happen if the condensate pump itself malfunctions.

To address this issue, follow these steps:

• Verify Power Supply: Ensure that the condensate pump is receiving power. A lack of power could prevent the pump from operating.
• Test Pump Functionality: If you’re using an external, third-party pump, check that it’s working correctly. Listen for the pump running and check for any water being expelled.
• Inspect Drain Line: Make sure the drain line is not clogged or frozen. A blockage or ice can prevent water from draining, triggering the safety switch.
• Examine Wiring Connections: Check all wiring connections for looseness, damage, or breaks. Faulty wiring can affect the operation of the pump and safety mechanisms.
• Check for Air Gap: Ensure there is an air gap in the drain line. This prevents a siphon effect which could lead to water backup.

Error Code 32: Outgoing Water Temperature Sensor Fault

Error Code 32 on your water heater indicates a fault with the outgoing water temperature sensor (thermistor). This error can be caused by issues ranging from loose connections to scale build-up. Here’s a concise guide on how to troubleshoot and resolve this error:

1. Inspect Thermistor Wiring Harness: Begin by checking the wiring harness from the thermistor to the PC board for any loose, broken, or damaged connections. Secure any loose connections and replace damaged wires if necessary.
2. Clean the Thermistor: With no water in the hot water supply lines, remove the thermistor and check for any scale build-up. Clean off any deposits or substances found on the thermistor to ensure it can accurately measure water temperature.
3. Check Thermistor Resistance:
   • Isolate the water supply and remove the thermistor from the water heater.
   • Use a multimeter set to read 20K ohms to check the resistance of the thermistor. Connect the meter leads to each end of the thermistor plug.
   • Apply heat to the thermistor bulb (e.g., by holding it between your thumb and finger). The resistance should decrease with heat and increase when cooled (e.g., when ice is applied).
   • Verify that the resistance values match the typical readings for different temperatures (e.g., 11.4 – 14K ohms at 59°F, 6.4 – 7.7K ohms at 86°F, etc.).
4. Re-install the Thermistor: If the resistance readings are correct, reinstall the thermistor. Make sure the small O-ring is intact and apply a small amount of grease or lubricant to prevent damage during installation.
5. Test for Leaks: Turn on the water supply and check for leaks around the installed thermistor.
6. Re-fire the Water Heater: After completing these steps, turn on the water heater. If Error Code 32 persists, it may be necessary to replace the thermistor.

Code 33: Heat Exchanger Thermistor Fault

This is same as Code 32, follow same process for this thermistor.

Error Code 34: Combustion Air Temperature Sensor Fault

This is same as Code 32, follow same process for this thermistor.

Code 38: Exhaust Gas temperature sensor Fault

This is same as Code 32, follow same process for this sensor.

Code 52: Faulty Solenoid Gas Valve

Error Code 52 on a water heater indicates a problem with the solenoid gas valve, which can involve issues with wiring or component failures. Here’s how to address this error effectively:

1. Inspect Flame Rod and Wiring: Start by examining the flame rod along with its wiring connections. Look for any signs of looseness, breakage, or damage. Secure any loose connections and replace any damaged parts to ensure proper functionality.
2. Check Gas Solenoid Wiring Harness: Inspect the wiring harness connected to the gas solenoid. Pay particular attention to the terminals to ensure they are neither loose nor damaged. Tighten any loose connections and replace the harness if you find damage.
3. Measure Resistance and Voltage:
   • On the PC Board, locate Connector D. Using a multimeter, check the resistance between the black wire at pin #27 and the yellow wire at pin #29. The resistance should be within the range of 18 to 22 ohms.
   • Measure the voltage across these pins while the water heater is trying to fire, which should be between 11 and 13 VDC. Reapply power to check the voltage to the gas valve during this process.
4. Replace Gas Valve and Venturi Assembly: If the previous checks don’t resolve the issue, proceed to replace the gas valve and venturi assembly. After replacement, if Error Code 52 still shows up, perform the reset procedure as outlined by the manufacturer.

Error Code 61: Combustion Fan Motor Failure

Error Code 61 on a water heater indicates a combustion fan motor failure. Here’s how to troubleshoot and potentially fix this issue:

1. Check Wiring Harness: Inspect connections from the fan motor back to the PC Board for looseness or damage. Repair or replace any faulty connections.
2. Inspect Fan Motor: Turn off power and gas, remove the fan motor, and ensure the blower wheel turns freely. Also, check the fan housing for debris and clear any obstructions.
3. SENSEI™ Series Models: For these models, make sure the check valve behind the fan motor isn’t stuck closed.
4. Measure Fan Motor Winding Resistance: Refer to the technical data sheet provided behind the front cover of the water heater or in the service manual to find the correct resistance values for the fan motor windings. Use a multimeter to measure these values. If the windings show an open circuit (no continuity), the motor needs to be replaced.
5. Evaluate Motor Condition: If the motor windings are within the specified resistance range and the motor itself turns freely, the issue might still be with the motor itself requiring replacement due to other internal failures not detectable by simple resistance testing.
6. Replace PC Board: If all the above checks are performed and the fan motor still does not function correctly, consider replacing the PC Board as it controls the motor and may be faulty.

Error Code 65: Water Flow Control Device Fault

Error Code 65 on your water heater indicates a fault with the water flow control device, typically involving the water flow servo. Here’s a simplified troubleshooting guide to resolve this issue:

1. Check Wiring Harness: Start by inspecting the wiring harness connections from the water flow servo valve back to the PC Board. Look for any loose, broken, or damaged connections and repair or replace as necessary.
2. Power Cycle the Water Heater: Turn off the power to the water heater, wait a few moments, and then turn it back on. Check to see if the error code resets and the issue is resolved.
3. Check Water Flow Servo Valve: If the water flow servo valve fails to close during the bath fill function, immediately turn off the water flow and stop using the bath fill controller. This prevents further complications.
4. Replace Water Flow Control Servo: If the above steps do not clear the error, replace the water flow control servo valve as it is likely faulty.
5. SENSEI™ Series Specific Measurements:
   • For SENSEI™ models, measure the voltage and resistance of the Water Flow Control Device on the PC Board at Connector (Plug D4):
     • Resistance: Check between the red wire (turns black before getting back to the board) at pin #30 and the pink wire at pin #20, as well as the white wire at pin #16 and the blue wire at pin #14. Both should read between 44 and 52 ohms.
     • Voltage: Measure between the grey wire (turns black before reaching the board) at pin #30 and the orange wire at pin #12. The voltage should be between 12 and 14 VDC.

Code 71: Solenoid Valve Circuit Fault

Same as Code 52, follow the process listed there.

Code 72: Flame Rod Fault

Code 72 on a Rinnai heater indicates a flame rod fault, which can affect the unit’s ability to detect a flame correctly. Here’s how to troubleshoot and potentially fix this issue:

1. Inspect Wiring Harnesses: Check the connections from the flame rod back to the PC Board for any broken or damaged connections. Repair or replace as necessary to ensure a good connection.
2. Position of Flame Rod: Make sure the flame rod is properly positioned to contact the flame when the water heater is operating. This is crucial for the rod to detect the flame accurately.
3. Clean or Replace Flame Rod: Remove the flame rod and check for any carbon build-up, which can interfere with its operation. Clean it off or replace the flame rod and its gasket if the build-up is significant or if the rod is damaged.
4. Measure Micro Amp Output: Using a multimeter, measure the micro amp output from the flame rod while the heater is running. It should maintain a minimum output of 1 micro amp to confirm proper function.
5. Replace Flame Rod and Gasket: If issues persist after cleaning, replace the flame rod and its gasket to ensure optimal performance and seal.
6. Check Heat Exchanger: Inspect the heat exchanger for any signs of leakage. A leak can affect the flame rod’s ability to detect a flame. Replace the heat exchanger if needed.
7. Replace PC Board: If the above steps don’t resolve the issue, replace the PC Board as it might be failing to interpret the flame rod’s signals correctly.
8. For SENSEI™ Series Models: After installing a new PC Board, transfer the settings from the old board to the new one using the data transfer cable provided. If the data transfer is not possible, manually program the board according to the step-by-step instructions included with the new component.

Error Code “LC, LC0-LC9”: Scale Build-Up in Heat Exchanger

The error codes “LC” or “LC0-LC9” indicate scale build-up in the heat exchanger. When reviewing maintenance code history, “00” may be used in place of “LC.”

1. Flush the Heat Exchanger: Follow the recommended flushing procedure to remove the scale build-up. Flushing Rinnai tankless water heater.
2. Important Note: The LC, LC0-LC9 codes are unique in that they allow the water heater to continue operating. The display will switch between showing the LC code and the temperature setting, and the controller will emit a continuous beep.
3. Resetting on Older Models: For older units, you can clear the LC code by turning the power off and then back on.
4. Post-Flushing: After completing the flushing procedure, be sure to reset the heater.

Understanding common error codes can help you troubleshoot issues with your Rinnai tankless water heater more effectively. However, while homeowners can handle basic troubleshooting, complex problems and repairs should always be managed by qualified professionals. Regular preventive maintenance and adherence to the manufacturer’s guidelines are essential for preventing errors and extending the lifespan of your Rinnai tankless water heater.

TanklessHelp.com, a Joseph-owned business, is here to assist you. If you’re within our service area and need help with your tankless water heater, please give us a call. We look forward to providing expert repair and maintenance services!