I think the Diplomat brand was made for MFI who no longer exist so you may have to pay for a user guide...search online.
There's often a rating plate with model details on the side face of the drop down door - stuck to the shiny piece.
Make sure you always use dishwasher salt - not table salt and buy it in 25kg bags - cheaper in bulk - in the big screw cap at the bottom.
Always use good quality rinse aid in the little flap door next to where the detergent goes.
Avoid the multi-tablets.
Good luck...
Peccavi
December 2009