The Error Code 11 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.
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 you do see flame in the burner for a second or two, that means the unit is not detecting ignition and troubleshooting would revolve around the flame detection system.
If the unit is failing to ignite then you are missing one or more of the 3 things needed for combustion:
- Air
- Gas
- Spark
With tankless units, you can almost always cross off “Air” as one of the contributing problems because simply removing the front cover provides the unit all the combustion air it could need. It’s still a good idea to visually inspect the cleanliness of the unit though as excessive dust, dirt or lint build up could indicate a contributing factor.
However, if you take the front cover off and the unit works properly and no longer has an error code 11 (or any other error code) you might have an issue or obstruction in the air intake venting preventing the needed air from entering the burner.
The troubleshooting outlined in this article is assuming the unit is failing to ignite regardless of the front cover being on or off and revolving around issues related to spark or gas.
Troubleshooting Spark:
Removing Air from the equation, you are left with just Gas and Spark. One or possibly both of those are missing and that’s why the unit is not igniting. More often that not, the ignition rod has accumulated build up preventing a spark from happening. The ignition rod can be pulled out and cleaned off with the rough side of a sponge, a piece of fine grit sandpaper or even a dollar bill. In some cases the ignition rod might have severe corrosion or pitting that renders a cleaning ineffective and it will need to be replaced. Additional causes of no spark are failed high voltage cords, a failed igniter and, least likely, but still possible a failed circuit board not sending voltage to the igniter. Troubleshooting is a process of elimination, start from where the spark occurs and work you way back to the circuit board. Chances are you will find the problem well before the circuit board though.
Troubleshooting Gas:
If you have spark then you’re looking at lack of gas as the cause. This could be related to a component inside the heater but more likely factors outside of the unit are preventing the proper amount of gas from reaching the heater. Those could be the gas meter, gas regulator (if applicable), gas line, gas shut off valves and in earthquake prone areas such as California, an earthquake safety shut off valve.
Troubleshooting gas issues should be left to a professional as there is some serious risk if you’re unfamiliar with what you’re doing.
Troubleshooting Flame but Still Error Code 11:
If the unit is igniting (you can see flame through the sight glass for a second or two) but still giving an 11 code, that means the unit is not detecting flame. The flame rod which is usually part of the ignition rod assembly or close to it might have build up that is preventing detection of the flame. It can also be cleaned the same way as the ignition rod. Additionally make sure the blue wire attached to the flame rod is connected and not damaged, pinched or broken. Finally the flame detection system relies on proper grounding of the unit so all green ground wires should be securely attached to the various grounding points inside the heater.
For further technical assistance call 866-766-7489 or use our Contractor Locator to find a local service representative.