I have the same leak problem, just slide the outer black cover down and it will come off, undo the six hexagon screws in the the yellow casing, it will then pull off, connect the hose to the inlet coupling and turn the water on you can then see where the leek is.
my leek is on the plastic inlet water pipe I must have left water in it and it froze and split the pipe, it is dead easy to replace and at the moment I am trying to find out where I can obtain a replacement pipe any ideas?
mike, April 2011