Hayward 2" union - is there a correct way for flow

[blakeusa]

Is there an optimal way (direction of the threaded coupling) on a Hayward style Union.

ie. should the threaded [ or larger side go with the direction of the water.

 

[JasonLion]

It doesn't matter.

 

[gtemkin]

If the union is on a vertical run you may want to put the half that has the o-ring groove at the bottom so you don't have to fight trying to keep the o-ring from falling on the ground when the union is separated.