The most common anticipated issue is an open circuit condition. Diagnostic steps for identifying the cause of the open circuit include checking the electrical contact between the catalyst and the WE contact ring, which can be done with the WE fixture removed from the cell, or by removing the CE fixture and membrane to enable line of site access to the catalyst surface so that it can be electrically contacted to check connectivity with the WE contact wire. The cause of an electrolyte-based open circuit conditions can be harder to identify. One strategy is to test the electrolyte fill of each chamber. For the WE chamber, replace the CE fixture and membrane with a transparent plate so that the presence of bubbles on the top of the cell can be visually observed. Similarly, operating the CE fixture with a transparent plate can be used to confirm electrolyte penetration through the porous counter electrode to the plate.