Troubleshooting Rinnai
Error Code 11

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How to troubleshoot and repair Rinnai water heaters when there is no ignition, followed by the error code 11. Check out for the 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 and what to look for after the error code 11 shows up on the remote controller and there is 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 and condensation.

Gas related issues

  • Make sure that there is no interruption in 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 right gas type.

  • There must be a proper gas pressure and according to the rating plate. There are several causes for the improper gas pressure; gas system was not properly sized (the manufacturer specs were not met), dirt and debris are present in the system.

  • Ensure that all air is removed (purged) from the gas lines, after the installation.

Igniter issues

  • Test the unit's igniter for proper work, by cycling the unit and checking is there a spark. If there is no spark, look for the loose, bad or no connection and damaged element. Verify the correct voltage on the electric board when the unit is in ignition cycle.

  • The igniter and its ceramic insulation must be securely tighten 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 carbon and scale buildup clean as instructed by the manufacturer.

Flame rod issues

  • Make sure that there is no loose connection in wiring of the flame rod(s), and that wiring is plugged into the correct rod.

  • Ensure that flame rod is properly located and installed tight in its mounting bracket.
  • Inspect the flame rod for debris and dirt - clean as needed and replace if there are cracks. With the rod, replace the gasket as well.

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Venting issues

  • Always look for the manufacturer's instruction for the correct vent installation; the recommended material, size, length and proper clearance around the vent. For example, an incomplete combustion (not enough fresh air, or blockage) leads to an incomplete combustion (yellow/red flame instead blue) and carbon build up on the flame rods.

  • Check the venting system (both intake and exhaust) for blockage.


  • Proper dip switch and gas pressure setup for the high altitude installations.
  • Check for water leaking and excessive moisture as it can lead to corrosion and wet electrical connections.

  • Check for proper drain of the condensate (condensing type).
  • Make sure the heat exchanger (the 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., PC electric board and/or gas valve might be malfunctioning resulting in its replacement.

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Pictures - courtesy of Rinnai WH company

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