After closing on our first home I noticed my press tank needed to be replaced. While doing so I installed a new press switch and a CSV as well for good measure. After opening up the pump controller I did some head scratching. I found that the wiring for thE original 3 wire pump had been reconfigured to that of a two wire pump, eliminating the need for a controller. I'm wondering why then would you want a three wire pump that requires an additional piece of equipment (pump controller) when a two wire pump does the same job without the added cost of a controller?