An error code 94 means the exhaust temperature is too high (condensing units). One of the benefits of installing a high efficiency tankless is the low exhaust temperatures that allow for the use of PVC, CPVC or PP venting (check local code to see if there are any additional restrictions)….

The Error Code 90 indicates an airflow or combustion abnormality. (Error Code 10 is also troubleshot with the same methods) To simplify it, the unit is either struggling to move air in or out of the unit or it is unable to hit the set temperature. For a newly installed…

The 73 error code indicates a circuit board setting issue. It is triggered by the following conditions: Any changes made to jumper wires inside the unit should be done with the unit disconnected from power. If you received a replacement circuit board please follow the directions included in the box…

The error code 71 indicates a malfunction in the circuit board, specifically in the Gas Valve drive circuit or its grounding system. This issue may be caused by a faulty soldering connection on the Circuit Board. In most cases, when this error occurs, the recommended action is to replace the…

The error code 20 means the High Limit Switch has been triggered. This error code generally requires a hard reset (unplugging or disconnecting power). The high limit switch is usually found on the copper pipe leaving the heat exchanger in a Pre-Mix style unit. The purpose of the high limit…

The 16 error code occurs when the outlet water temperature spikes to an abnormally high value. The heater will restrict its water flow as an additional precaution. The error code is reset by unplugging the heater, waiting 20 seconds, and plugging it back in.  Common causes for the 16 error code…

An error code 14 indicates a significant overheat of the heat exchanger has occurred. Much like a fuse in automotive applications or other electrical uses the thermal fuse is a one time use part as it is physically broken once it’s tripped by an overheat. The thermal fuse is wrapped…

An error code 12 indicates a flame loss. This means that the unit is detecting a flame, but the flame is being extinguished during operation (weak flame). Most of the same troubleshooting used in the Error Code 11 article can be applied to the error code 12 such as cleaning the flame rod…

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…