Troubleshooting Rinnai
Water Heater
Error Code 11

Rinnai tankless water heaterRinnai

How to troubleshoot and repair Rinnai water heaters when there is no ignition, followed by the error code 11. Check out for possible causes that generate the error code 11 on the digital display of the heater, and explore potential solutions.

Here is the summary of what can go wrong with your Rinnai water heater and what to look for after the error code 11 shows up on the remote controller. This includes the following:

  • No flame in the combustion chamber
  • Gas installation with the gas regulator
  • Piping and control valve
  • Combustion chamber with the ignition rods
  • Burner
  • Fan
  • Debris
  • Deposits
  • Venting issues
  • Leaking
  • Condensation

Gas related issues

  • Make sure that there is no interruption in the gas supply to the water heater.
  • The gas type must be according to the rating plate found on the unit. The dip switch on the electronic board must be set for the correct gas type.
  • There must be a proper gas pressure and according to the rating plate. There are several causes for the improper gas pressure; the gas system was not correctly sized (the manufacturer specs were not met), dirt and debris are present in the system.
  • Ensure that the air is removed (purged) from the gas lines after the installation.

Note: As extensive knowledge and skills are needed for any gas work, including the gas license possession, the best is to contact a licensed technician.

Igniter issues

  • Test the unit's igniter for proper work by cycling the unit and checking if there is a spark. If there is no spark, look for the loose, bad, or no connection and the damaged element. Verify the correct voltage on the electric board when the unit is in the ignition cycle.
  • The igniter and its ceramic insulation must be securely tightened to the mounting bracket and in the correct position. A loose rod can cause no sparks or create a short if it touches other metal components. When installing a new element, make sure to install a new gasket too.
  • Inspect the igniter and if there is a carbon or scale buildup clean as instructed by the manufacturer.

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Flame rod issues

  • Make sure that there is no loose connection in the wiring of the flame rod(s) and that the wiring is plugged into the correct rod.
  • Ensure that the flame rod is located correctly and installed tightly in its mounting bracket.
  • Inspect the flame rod for debris and dirt - clean as needed and replace if there are cracks. Replace the gasket as well.

Venting issues

  • Always look for the manufacturer's instructions for the correct vent installation, the recommended material, size, length, and proper clearance around the vent. For example, incomplete combustion (not enough fresh air or blockage) leads to incomplete combustion (yellow/red flame instead of blue) and carbon buildup on the flame rods.
  • Check the venting system (both intake and exhaust) for blockage.


  • Proper dip switch and gas pressure set up for the high altitude installations.
  • Check for water leaking and excessive moisture as it can lead to corrosion and wet electrical connections.
  • Check for the proper drainage of the condensate (condensing type).
  • Make sure that the heat exchanger (and space between fins) is clean from debris and dirt, so as the gas burner - to prevent irregular combustion.
  • If all the above issues are corrected, and the unit is still not operating per specs., the problem might be with the PC electric board and/or gas valve, requiring their replacement.

    A licensed technician should replace any sensitive elements, such as the electronic board or gas valve.
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