I have two of those boxes.one has only 1 spring screw the other has two I am trying to boost pressure for my I

Irrigation system I got the pressue about 45 lbs but I will run for awhile and drop to 30 or less and stays there what do I do next thanks Joe.

Joe, I am not much of a well man but from what you say your issue isn't pressure it is volume. What diameter are material are your pipes. How is the pump rated?

Pvc pipes 1" then 3/4 to irragation don't know what pump is rated for

There are a few well guys who will eventually stop by if we keep this thread alive. I think the GPM of the pump is at issue. If a 3/4 pipe running full open can cause a drop in a 1" pipe then the pump is not doing enough. What do you other plumbers think?

We are assuming this system has a pressure tank. Is that correct?

Other than that question, I think BG is exactly correct. Your well can only deliver enough volume of water to maintain 30# of pressure through your system. I would think that you have 45# of pressure when you start irrigation, but as the minutes go by and the tank's reserve is used down, the pressure finally drops to 30.

It is not a switch issue, though I can't imagine why you would have two switches. You have only one pump, correct?