It is often confusing when sizing a pump union. All the pumps in this section are sized as per USA imperial pipe size reference. Although we refer to 2 inch, 1.5 inch and so on, often the outside diameter of the threaded connection on the inlet and the outlet of the pump will be bigger than the size referred to. The term 2" or 1.5" etc. is more a reference to the union sleeve which is connected to the pipe work.
When we state an inlet and outlet size the information below will apply.
2.5 inch = 90mm Ø, 2 inch = 75mm Ø, 1.5 inch = 62mm Ø, 1 inch = 48mm Ø.