If you own a tankless water heater, you’ve invested in a smart system that can provide endless hot water for over two decades. While these systems require less maintenance than traditional tank water heaters, occasional issues may arise. Adelaide Emergency Plumbing is here to guide you through Rinnai tankless water heater troubleshooting, focusing on these exceptional units known for their self-diagnostic capabilities.

Why Rinnai Tankless Water Heaters Are Great

Rinnai tankless water heaters are equipped with a self-diagnostic tool, continuously monitoring the unit’s performance. When something goes wrong, the unit displays an error code. Understanding these error codes can help you identify the problem and determine if you need a plumber or if it’s something you can handle yourself.

Common Rinnai Error Codes and How to Address Them

Error Code 02: No Burner Operation During Freeze Protection Mode
Solution: Call a plumber.

Error Code 03: Power Interruption During Bath Fill
Solution: Turn off all hot water taps, press the On/Off button twice, and turn hot water back on. Repeat if necessary.

Error Code 10: Air Supply or Exhaust Blockage
DIY Steps:
Check venting material (use Rinnai-approved materials).
Look for blockages in the flue inlet or exhaust.
Ensure proper connections and check the condensation collar.
Confirm dip switches are set correctly and the fan is rotating.

Error Code 11: No Ignition (Heating Not Turning On)
DIY Steps:
Check gas supply, propane tank (if applicable), and grounding.
Verify proper gas type and pressure.
Ensure dip switches are set and the appliance is grounded.

Error Code 12: Flame Failure – No Flame
DIY Steps:
Check power supply for loose connections and correct voltage.
Inspect the flame rod wire for proper connection and carbon build-up.
Check for DC shorts at components.

Error Code 14: The Thermal Fuse Has Been Activated
DIY Steps:
Check for air flow restrictions.
Examine the heat exchanger for scale build-up.
Follow the owner’s manual to flush the heat exchanger.

Error Code 16: Over Temperature Warning
DIY Steps:
Check for obstructions in the combustion chamber, exhaust piping, and heat exchanger.
Improve airflow and water flow to resolve the issue.

Error Code 32: Outgoing Water Temperature Sensor Fault
Solution: Examine the sensor for damage or scale build-up; replace if necessary.

Error Code 33: Heat Exchanger Outgoing Temperature Sensor Fault
Solution: Similar to above; carefully examine and replace the sensor if needed.

Error Code 34: Combustion Air Temperature Sensor Fault
Solution: Check sensor and wiring for damage; replace if necessary.

Error Code 52: Modulating Solenoid Valve Signal Abnormal
DIY Steps:
Check wiring harness for loose or damaged terminals.
Measure resistance of valve coil.

Error Code 61: Combustion Fan Motor Failure
DIY Steps:
Check fan rotation and wiring harness for damage.
Measure motor winding resistance.

Error Code 65: Water Flow Control Fault
Solution: Call a plumber.

Error Code 71: Solenoid Valve Circuit Fault
DIY Steps:
Check wiring harness to all solenoids.
Measure resistance of each solenoid valve coil.

Error Code 72: Flame Sensing Device Fault
DIY Steps:
Check if the flame rod is touching flame.
Examine wiring and clean the flame rod; replace if necessary.

Error Code 00 or “LC”: Scale Build-up in Heat Exchanger

Solution: Call a plumber for heat exchanger flushing or replacement.
Note: Don’t ignore the “LC” code; even though it allows the unit to run, it indicates scale build-up that needs attention to avoid future problems.

If you need assistance with Rinnai tankless water heater troubleshooting or any plumbing concerns in Adelaide, contact Adelaide Emergency Plumbing. We’re the hot water plumber Adelaide residents trust for prompt service and repairs. We are here to help you keep your tankless water heater running smoothly!