Well Pump Pressure Switch

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 settings

Square D pumptrol pressure switch settings

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.

Meyers jet pump pressure switch setting

Meyers jet pump pressure switch setting

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.

Square D pumptrol pressure switch wiring

Square D pumptrol pressure switch wiring

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No comments yet to Well Pump Pressure Switch

  • How many turns of the screwdriver do you need to do to increase PSI by 10?

  • There is no easy answer to that question. It depends on the pressure switch type, etc, etc. You may never get 10 more PSI out of your current switch, or you may be able to do it in a few turns. I suggest you try one turn at a time (clockwise) and see what the result is. If it gets too hard to turn, stop, you have reached the end of the useful range of your pressure switch.

  • John

    My water pump shuts off at 60 psi and when you turn on the taps, the pressure gauge will go to 20 psi and then drop to zero before the motor starts after a delay of a few seconds. I run out of water pressure for these seconds until the pump starts again. Should I increase the 20 psi for the pump to turn on sooner or do I have another problem?

  • Sounds like you have a different problem. After the pump starts, how long does it run before it shuts off? Also, does the pump run for as long as you have the tap open, then shut off when you turn off the tap?

  • John

    The pumps runs until it reaches 60 psi and does shut off. When the tap is open and the pump is running it will keep running until we shut the tap off and then it will reach the 60 psi and then it will shut off.

  • John, sounds like you have a water logged pressure tank. When is the last time you added air?

  • John

    How much air should there be?

  • Usually about 30 psi with the tank empty. You can read Water logged pressure tank which should give you some good information.

  • Fred

    I hope this is the simple side of a problem. Well has a new submersible pump;
    Very old tank recently replaced with 44 gal. reading 45psi; new sq. D pumtrol pressure switch; new gauge next to it reading 40. Problem is, Turn on the faucet at the well and it pumps water for 10 seconds and shuts off. Gauge immediately goes to zero. I changed pumptrol srews 1 and 2 with no difference. Well still pumps water for only ten [+/-] seconds. If I turn the power off at the pump and back on and then open the faucet, it will again pump for 10 seconds. Please tell me all I have to do is
    turn around three times, break the lead of my number two pencil, bite off the eraser, sneeze once, and the water will flow. Thanks for any and all help.


  • Hi Fred, One question, what happens to the pressure gauge during all this? Does it go up to 60 PSI, then the pump shuts off, or does it stay at 40 PSI?

  • Fred

    Hi Paul,
    When the water is turned on the gague reads 40/42 and when it shuts off, the gauge immediately drops to “0.” I checked 3 wells functioning here in the area; gauges all read 42/44 about, and all set up the same.
    I took card stock and made a depth gauge for the two screws, big and small[D Pumptrol]. This well-gauge now also reads 42 to 44. Here is the difference; Power on, open faucet at the well, water flows about the same strength as another well. Ten seconds and the well shuts down, water ceases. Gauge drops immediately to “0.” Another interesting part. Wait 20 minutes or so, turn the power off and back on and the gauge goes immediately, rapidly, to 40/42. And, I hear the pump motor run but for only about five to seven seconds.

    The submersible and the Franklin box were installed about a year ago in a well that probably had not been used for twenty years. No water. Pro said, “It’s the tank.” Now, all above ground components new.
    One added point, when I turned the power on and off after about a twenty minute wait and the gauge went immediately to 42, I turned the water on but this time it ran for only about 3 or 4 seconds. There is an answer in the above information somewhere. Unless, the pro may have installed and wired the submersible wrong? Yikes.

    It is my neighbor’s well. He runs a maintenance service in the city and does build and wire houses to code, but has never worked on a private well. We installed the above ground components two weeks ago. I know it went together right. There is an electrical quirk somewhere. So, Paul, where lies the clue, the solution?

    Thanks, Fred

  • Fred,
    First, the fact that the pressure goes from 0 psi to 42 psi rapidly means your pressure tank has no air in it. The reason I say this is because gases, such as air, compress, while liquids do not. The pump turns on and the pressure increase is rapid because the tank is filled with non-compressible water. The tank pressure reaches the pressure switch cut out and the pump turns off. To give you an idea, my pump runs for about 2 minutes to bring the pressure from 40 to 60 PSI, longer if the water is running somewhere in the house. You may indeed need a new pressure tank if you cannot recharge this one with air, however…

    Second, have you checked the amount of water in your well? It sounds like the pump motor is cutting out (from what you say about turning the power off and back on again). Most pump controllers are able to tell when the pump motor is running dry and will turn it off before it melts down. This may be the actual problem that is causing your pressure tank issues. I would hire a well pump person to come and look at it, because to me, it sounds like you have more than one problem.

  • Gary

    My pressure cut in is around 24 psi, the cut out is around 72 psi, is that to high? I’ver tried adjusting the number 2 screw counter clockwise to decrease the pressure. It doesn’t seem to have dropped the pressure. Do I keep adjusting the number 2 screw until I see a substantial drop in pressure? Thanks for any help you can give me.

  • Gary

    In reference to the previous email I wanted to provide you with additional information on the type of pump we have. Square D pumptrol, 20 gal. tank, max working pressure 125 psi, and the on is 30 and the off is 50. What steps do I need to take to adjust this to these numbers, given that they are running at 24 and 72 referenced in the previous email?

  • Gary,

    I would turn the number 1 screw count clockwise 1-2 turns and turn screw #2 clock wise 1 to 1.5 turns. Your cut out pressure is too high, at 72 psi it must feel like a sand blaster. 50-60 PSI is really the maximum you would want to see coming out of a shower head. It that does not work it may be time to replace the switch. Pressure switches can get gunked up etc over time.

  • hello, i’m trying to figure out why my lawn pump(shallow well centrifugal wayne 1 1/2 hp)keeps cycling on & off about every 10-15 minutes. the square d pressure switch is a 20/40psi. my captive air tank is good(no leaks found) and charged @ 18psi. i found a very small leak at one of the zone valves(a very slow drip) and don’t think its enough to draw down tank in 10-15 minutes. any advice on how to troubleshoot/correct this would be greatly appreciated. thanks, mark.

  • Mark, It sounds like you may have a bigger leak somewhere else, possibly a check valve or foot valve (well side) is not closing all the way??? That would make the water flow backwards, back into the well. You have verified that your pressure is 20-40 PSI? Sometimes the spring on the pressure switch gets tired and you may get a different cut in/cut out. Those are the only things that I can think of.

  • darryl

    hi my switch wont cut off i have the pumptrol 40-60. would the pressure gauge that dont work do this? and also when it gets cold outside it wont come on. Thanks

  • Darryl, this should have nothing to do with a pressure gauge. It sounds like you have a tired spring inside your pressure switch, or it is getting stuck on something. You may need to replace the whole switch or call a plumber.

  • kevin

    i changed out my deep well jet pump(two pipe) and have this problem maybe you can help:

    when the pump runs pressure gage reads 0 psi, and it will not shut off, when i kill the power to the pump the pressure gage jumps up to 40 psi, i am getting water out of it.
    IS this a primeing issue seems, the primer plug is filled..
    any help would be appreciated

  • Rick

    I had to replace my check valve, to do so I had to remove both pipes from the pump. pump was placed, carefuly, on it’s side, D pumptrol facing up, to remove rotted mounting bolts. hooked it back up, knocked in a bunch of rust and hardened lime stone when primimg pump by accident. When 40 PSI is reached, the contacts on the pumptrol snap on and off like a machine gun. Playing with the set screws only slows down the maching gun effect. Have to shut off pump at the breaker. What the heck did I do ? I’m thinking crap got into the pumptrol line. I don’t know. Thinking of replacing it.

  • kevin

    actually i determined that when the pump runs is suppose read 0 psi, and after adjusting the cut on cut off adjustment, the pump would cut off and on like it suppose to, it just wont build up any pressure past 40 ps, hits 40 and wont build up any more pressure.

    i checked the pressure tank when empty and it had about 26 psi, when pump runs and cuts off tank supposely full it has about 45 psi on the tank, the tank is a 20 gallon tank and to me it seems light.

    after buying the pump and installing it i found the tag for the well witch is 165ft deep water line at 125, the pump and all the deep well jet pumps i l;ooked at say they have a max vertical distance of 90 ft which probally why it wont build up past 40psi, also may be the jet or foot valve itself…….just a guess, probally should of switched to a submersible.

  • kevin

    make sure there is no air in the pressure line to the pressure switch, loosen the line enough at the the switch to allow some leakage that should allow any air trapped to escape. you could also remove the line all together and turn on the pump to flush it, if it chatters with the pressure line disconnected the pressure switch needs replacing. careful with that as water and electricity done mix

  • David

    I’m having some problems keeping my water going in my home. About 2 weeks ago it snowed 2 feet than melted – then snowed 2 feet and once again melted. Needless to say, around 6 pm on night we lost water in the house. I went to the pump house – opened up the doors and there was about 3 feet of water in it. My pressure tank was kinda floating (as much as the make to pluming would allow) and the wate was over my pressure switch. I Drained the water. Then I sat the tank back into position and replaced the pressure switch. The water came right back on!

    2 Weeks later (today) the water again went out. It’s 3 degree’s out. I assumed that now the pipes had frozen but that’s not the case – heat tape working good. Pump house clear of any water – Sump pump doing it’s job. So I took of the pressure switch cover, turned of the breaker (the connection were apart) I pushed on them -, turned on the breaker and they closed for about 5 seconds then reopened. Water was back on in the house…? he water stayed on for about 10 mins (we are keeping it on a trickel so the pipes don’t freeze) but it stoped again. So… out to the pump house I go, take the cover of the switch and (with caution) and a plastic fork (LOL) i pressed the connectors togather. I can hear the pump kick on. I keep them togather for about 60 secs and the water stays on for about 10 mins – then same thing.

    Can you please tell me what might be the problem?


  • Sounds like the pressure switch is bad, or set incorrectly. Do you have a pressure gauge on your tank? If so, is the pressure where it should be? That is the best way to diagnose this problem. Other problems could be bad pump controller (assuming a submersible pump) or, as you already mentioned, frozen pipes.

  • David

    The only pressure gauge on the system is located on a faucet directly under the pressure switch – it always reads zero – it read zero before all this happened. Is there normally a conection on the tank where I can add a pressure gauge?

    I don’t think it’s frozen pipes because it works (water will run for about 10 mins) if I manually force the connectors on the switch?

    When I put the new pressure switch on about 2 weeks ago I didn’t adjust it at all – it just worked. What are the settings when they leave the factory? I kind’a assumed that they would be set already.

    Thanks for your quick response!


  • David

    I was thinking – maybe the small 1/4 inch tubing that the pressure switch sits on top of is freezing. So . . i put a heat lamp on it – would that cause the pressure switch not to close if the pipe is frozen?

  • That could keep the pressure switch from not working right

  • Al

    We are having a problem with our pump or pressure switch. We have replaced 2 pressure switches, a new water tank, put a check valve before and after the pump, but the same problem occurs. When it pumps up to the right pressure 40-50 psi the pressure switch starts to chatter. Going on and off rapidly. Do you have any ideas. We have tried 20-40 and 30-50 pressure switches. Doesn’t make any difference.

  • Al

    Well, we have tried everything we can think of. We have now put in a new pump and another pressure switch. Does anyone have any suggestions?

  • garry back

    i put a new pressure switch on i have a black white and green wires i put the two black wire in the middle screws and the white one on the out side screws when i plug it in it throws the braker do i have it wire up write

  • garry back

    well i wired it up like your picture but i put the white were your red wires were and that work.now i got to get the foot value on stuck so it will drall up write dont want to dig it up with ground frozen.thank if you reply to the other one

  • Terry

    I have the two threaded screws on my regulator. I’m new to this well/septic system and didn’t know what to do to increase the pressure from the well, so, as usual, I started tinkering. I started with low end at 30 and top end shut-off at 50. I have now turned each of the adjustment nuts two turns clockwise. The top end pressure is now 65, but the bottom end (turn-on pressure) is still about 30. Can I increase the low end to 40 or not? Thanks–

    Terry in Texas

  • jim

    this is in response to the pressure switch chattering. i stumbled onto this discussion group while helping a buddy out tonight. we had installed a new motor/pump/tank assy. last night. pump has been sproadically chattering ever since. i had him check the bladder pressure WITH THE TANK DRAINED. he measured 40 psi. he bled it down to to around 30 psi. and tells me it’s now working.

    my guess is that, if it were at 40 psi empty, then it’s even higher when filled with water. now run the pump briefly and ya got even more pressure. my take is that it quickly (almost immediately) reaches the cutout of 50 prematurely. then, the pump kicks out, and you’re close to the cut-in pressure. i think that’s when it starts to oscillate.

    just my simple take.

  • Jim,

    Sound right to me, on a bladder tank, the pressure with the tank empty should be at least 5 psi below the pressure switch cut in (low pressure on). See this post about pressure tanks and this post about water logged pressure tanks for more info.

  • Steve

    I’m having a problem with my water well system. When running the water and watching the pressure gauge the system pressure slowly goes down to approx 30psi then just drops to zero real fast. the pump will then after approx 5 sec kick on and the pressure gauge jumps to 30 psi and slowly builds to cut out pressure approx 50 psi. I have drained all the water from my system and checked the air pressure in my pressure tank, it shows to be 27 psi. and the tank when wiggled appers to be empty. I thought maybe i had a pluged r restricted stand pipe to my pressure switch, I removed my pressure switch and pushed a wire threw the 1/4 pipe, the pipe was clear. i replaced the pressure switch with a new 30/50 pressure switch and the pump when the same problem, (droped to zero) never came on at all, i attemped to adjust the switch, by adjusting both the adjusting screws and have really got myself in a mess, how do i get the pressure switch back to the correct settings?, can i heve a air lock on the water side of my pressure tank that needs to be bled out? please help. thanks Steve

  • Steve,

    You have a bladder pressure tank and the bladder has too much air in it. Read the post about Well Pressure Tanks for a general discussion. I would find the air fitting, should be somewhere on the top of the tank, and reduce the pressure to around 24-26 PSI. You can use a tire gauge to check the pressure.

    Once you do that, reset both screws to there mid point settings and then you will have to adjust them by trial and error.

  • Sandy

    We have TOO much water pressure! How do we turn it down? We have a pump in a well and a pressure tank in the house. The guy who installed a sediment filter for us turned up the pressure to compensate–I assume at the pressure tank. We need to turn it down. Any help is appreciated!

  • adrian


    This is for anyone who can help me.I am having a problem with the plastic insides of my pressure switch getting too hot and melting causing the contacts not to open and close properly thus causing the pump to malfunction.The pump was installed new about 4 years ago but the last year or so I have had to replace the pressure switch numerous times say once every 3 or 4 months.The people at Lowe’s seems to think I have an electrical problem and it’s not in their switches.They also told me not to use connectors at the end of the wires just tighten the wires from the pump and from the house (220 I think) snugly under the contact screws.Can anyone help?

  • Sandy, I’d call the guy who installed the water filter and have him come back and turn down the water pressure to your satisfaction. Barring that, read the above article and I’d suggest you turn screw #1 anti clockwise.

    Adrian, It sounds like you have an electrical overload. Time to call a professional and have them look at it.

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