As I understand it, if you have the proper fittings already installed on your system (if not, adding them would increase the first-time costs), you need a pump, some tubing, and a bucket. I'm sure you could make it look prettier. Since you'd probably want a SS pump, that would be the biggest expense. You want something that would stand up to the mild acid you'd be pumping through the system. Depending on your water hardness, you may want to do this once a year, so purchase of the machine or making one seems like a good purchase to keep it running at full efficiency and capacity. A water softener would probably extend the time in between when this needed to be done. Essentially, you shut the thing off, isolate the supply and output, then pump the mild acid through the guts of the thing until you've disolved all of the mineral deposits, flush the thing with fresh water, then reopen the lines and turn it back on. A food grade vinegar should be enough. The owner's manual may describe the procedure.