On the pressuer switch there are two adjusters, big spring, and little spring. Pressuer switchs normaly come preset. I have a good but used pressuer switch. How do I adjust the pressuer switch manually.

How do I adjust the pressuer switch manually


The larger nut in the pump pressure switch: Usually the larger nut in the pump pressure control switch adjusts the pump cut-on ("cut-in") AND pump cut-off pressures simultaneously. That means that whatever the gap is between the cut-on pressure and the cut-off pressure, that gap is maintained, but the entire operating range of the pump is raised or lowered. Turning the large nut clockwise RAISES BOTH the cut-on and cut-off pressures. So turning the large nut clockwise shifts the whole operating pressure range of the pump UP to HIGHER pressures.
Conversely, turning the large nut counter-clockwise will lower the whole pump operating range. This is the simplest adjustment to make.
The small nut in the pump pressure switch: this nut is used to narrow or widen the gap between the pump cut-on and pump cut-off pressures. Turning the small nut clockwise (tighter) will RAISE the CUT-OFF pressure, and vice versa, loosening or turning the nut counter-clockwise will lower the cut-off pressure. Watch out! If you loosen this nut too much you can set the cut-off pressure below the cut-on pressure and the pump will turn on and run forever (or until it burns up.)
Which nut to turn in the pump pressure switch control, and which direction to turn it, are usually visible on a label inside the pressure switch cover.