Jerry,
Yes, it will work with the retrofit kit installed. It has two functions. One, it will purge the air out of the fuel system after changing the filters. Two it will drain water in the fuel/water separator bowl after the light indicates that is sees water in the bowl of the filter to a given level.
In each case the push of the button activates each operation respectfully. To test the operation just push the purge button and see if you hear anything running. If not, something is wrong with the power or control panel.