I like lots of water pressure… remember the episode of Seinfeld when they were buying and installing large wasteful shower heads on the black market? I am that guy. I like my showers to have an average pressure slightly less than that of a sand blaster. Since I have my own well, I can be that guy without really feeling guilty that I am wasting everyone else’s water. To that end, the shallow well jet pump I installed last year had its pressure settings much too low. I can’t abide by that, so I went a tinkering with the pressure switch to get the pressure up to about 50 to 60 PSI.
Here is what I found: There are two main types of pressure switches on any type of well pump; Square D pumptrol, and everything else. Fortunately the all work on the same principle. The cut-in pressure is the low pressure limit that tells the pump when to turn on, the cut-out is the high pressure that tells the pump when to turn off. The differential is the difference between the two, usually about 20 PSI.
To some extent, the cut-in/cut-out pressures are predetermined when the switch is manufactured. If your pressure switch specifies a range of 20 to 40 PSI, then you will not be able to make it run at 40 to 60 PSI no matter how much you adjust it. That is because the switch operates using an internal spring to select it’s cut-in/cut-out. In order to make a lower pressure switch operate at a much higher pressure, the spring would have to be replaced, and you might as well replace the whole switch if you are going to that trouble. You can however, make adjustments in the 5 to 10 PSI range using the adjustment screws on the switch.
Square D pumptrol pressure switch
Safety note: See those wire screw terminals there? That is 240 VAC, so you want to turn off the breaker before you go poking around with a screw driver.
There are two pressure adjustment screws; one will adjust the cut-in and cut-out pressure, the other will only effect the cut-out. On a pumptrol switch, these screws are called number 1 (cut-in and cut-out) and number 2 (cut-out only). Those folks at square D are clever that way. To increase the cut-in and cut-out, turn screw number one clockwise, to decrease turn counter clockwise. To increase the cut-out pressure only, turn screw number 2 clockwise, to decrease, turn counter clockwise. Most every pressure switch works the same way.
Made in China pump pressure switch
The jet pump did not have a Square D pressure switch, it has something that looks like it was made in China. I was thinking it would not be difficult to replace it with a better switch, but then I thought, why bother? I am going to be putting the new well on line soon anyway, right? Right.
Update: This is a picture of the pressure switch with the wires attached. The diagram that comes with the switch shows a slightly different way to wire it, either way will work. I like to match colors so that the red wire is connected to the red wire, etc. Then again, thats just me, I suppose.