Can my new pressure switch's range be adjusted to match the original?
Depends on the switch. 

The particular one (it's also a Square D, but they make various models) I have on my well is a 20 PSI differential and can be adjusted from 20/40 to 40/60 (perhaps beyond, I don't recall right now.) Check the instructions (should be in the box if it's brand-new, or look up the exact model number on-line.)

Instructions for the 9013 Pumptrol show a larger nut (1) and a smaller nut (2) with the following instructions:


  Adjust in the proper sequence:
  1. Range: Turn nut down (CW) for higher cut-in pressure, or up
  (CCW) for lower cut-in.
  2. Differential: Turn nut down (CW) for higher cut-out pressure, or up
  (CCW) for lower cut-out.


I will warn to be sure that power to the circuit is off at any point when adjusting the nuts - with the cover off to access the nuts, the line power contacts are exposed, and I prefer the level of being careful that shuts that off at the breaker to the level of being careful that is "I should avoid touching those."