Troubleshooting Noritz Tankless Error Code EC11: Ignition Failure

Troubleshooting Noritz Tankless Error Code EC 11

An 11 error code is an ignition failure. In other words, the unit recognizes there is a demand for hot water but for some reason is not able to ignite. This usually means there is no spark or insufficient gas entering the burner for ignition. In some cases the 11 error code could also occur when the unit ignites but fails to detect ignition via the flame rod

Troubleshooting Noritz error code 11, follow these steps:

The first step in troubleshooting is using the small sight glass built into the burner to observe if the burner is actually failing to ignite or failing to detect ignition.

If the unit is failing to ignite then you are missing one or more of the 3 things needed for combustion:

1. Air

2. Gas

3. Spark

With tankless water heaters, "Air" is rarely a contributing problem since removing the front cover allows the unit to access all the combustion air it requires. However, it’s still prudent to visually inspect the unit for dust, dirt, or lint buildup, as excessive accumulation could indicate a contributing factor.

This leaves "Gas" and "Spark" as the likely culprits. One or both may be missing, which is why the unit isn’t igniting. A common issue is buildup on the ignition rod, which prevents sparking. The ignition rod can be removed and cleaned using the rough side of a sponge or even a dollar bill. In cases of severe corrosion or pitting, cleaning may not suffice, and the ignition rod will need replacement. Other potential causes of no spark include failed high-voltage cords, a faulty igniter, or—though less likely—a malfunctioning circuit board that doesn’t deliver voltage to the igniter. Troubleshooting should proceed methodically, starting where the spark occurs and tracing back to the circuit board. Typically, the issue is identified well before reaching the circuit board.

If spark is present, the problem lies with the gas supply. This could involve a component within the unit or external factors that obstruct the proper flow of gas to the heater, such as the gas meter, gas regulator (if applicable), gas line, shut-off valves, or, in earthquake-prone regions like California, an earthquake safety shut-off valve.

Gas-related troubleshooting should be handled by a professional due to the significant risks involved for those unfamiliar with the process.

If the unit ignites briefly (visible flame through the sight glass) but displays an 11 code, it indicates the system isn’t detecting the flame. The flame rod, typically part of the ignition rod assembly or nearby, might have buildup preventing flame detection. It can be cleaned similarly to the ignition rod. Additionally, verify that the blue wire connected to the flame rod is secure and undamaged—not pinched or broken. The flame detection system also relies on the unit being properly grounded, so ensure all green ground wires are firmly attached to the grounding points inside the heater.

If you are experiencing the Noritz error code 11, you may take the following actions:

• Contact Amor Plumbing: Reach out to Amor Plumbing for professional assistance to diagnose and resolve the issue effectively. We service all customer in the following counties: If you are in Santa Clara, Alameda County, Contra Costa, and San Mateo County.

  
  

• You can reach Amor Plumbing in the following ways:

  • Online Contact Form: Submit your inquiry through our online contact form

  • Phone Call: Give us a call at (408) 649-3129

  • Text Message: Send a text to (408) 649-3129 include your Noritz model, serial number and a photo of your installation for faster assistance.

• Use the Noritz Contractor Locator: Visit the Noritz website to use their contractor locator tool to find a certified technician or plumber near you to better se

If you are uncertain about the coverage of your Noritz tankless water heater, contact Noritz Technical Service at 866-766-7489.