Adjusting Pumptrol pressure switch Range

Hi All,
I hope not too far off topic.
My well pump is not able to make 50psi anymore and I don't have the cash to replace it. It is making about 40psi reliably so I adjusted
the pressure switch Range to cut out at 38psi. BUT, because that is a "range" it now waits until 18-psi before coming on. The spec sheet states the stock Range is 30 to 50.
I want to shorten the Range so it cuts in around 25 and out at 35. I have a 200 gallon pressure accumulator so hunting on/off will not be a major problem.
My guess is to cut some off the length of the Range spring or try for a lighter spring.
Anyone ever played with this stuff? Suggestions?
I have emailed Square-D but still waiting on a reply.
Thanks in advance.
Dave
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I have three Square-D Pumptrol switches on my property, and one at work. All of them have TWO adjustment screws. One adjusts both the cut-in and cut-out pressures simultaneously, the other adjusts either the cut-in or the cut-out (can't remember) only. They're interactive, of course, so it takes a few tries to get both the desired cut-out pressure AND the range adjusted to your liking.
The newer ones with the side cutoff lever (like an air compressor switch) also have a nifty feature where if the pressure drops significantly BELOW the cut-in pressure, the switch will shut off, and has to be manually reset. That's nice, because a loss-of-prime or burst feed pipe won't burn out your pump.
Don't make the range too small, or you'll exceed the starting duty of the motor. Most pump motors can run continuously (with water), but don't like to be started more often than once every couple of minutes. The good ones don't care... like a "true" US-made Goulds. But the offshore pumps are really crap. You can expect three or four years out of one of the Chinese-made Lowes or Home Depot Sta-Rite types, where a top-of-the- line US-made Goulds or Sta-Rite might last twenty.
LLoyd
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Hi LLoyd,
Thanks for the reply. I am OK at adjusting the switch, but the problem is that Range is a 20-lbs differential and adjusting the main screw just moves that Range up and down. Having moved the cutoff down to 35, it now cuts in at 15. The other adjustment screw is to increase the cut off pressure and increase the range upwards so you can have 30-cut in and 60 cutoff for a differential of 30-lbs. I need the opposite of that and move the cut-in higher for a differential of 10-lbs.
As I mentioned in the original post, the 200-gallon accumulator will prevent rapid cycling even with the range reduced to 10-lbs differential.
Dave
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You're (I think) missing the point. You can control both the range and the cutoff pressures with those two screws. It takes a knack, and some experimentation, but you can.
My house has lousy "flow control" elements in all the fixtures. Some are simply not removable without destroying the fixture. I've had to do the same thing you need to. In my case, it was raising the top-end pressure, but also shrinking the range. But I can "go either way" on the Pumptrol units. Play with it awhile, and you'll figure it out. It's not intuitive.
LLoyd
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Why not just replace the impellor? Usually a drop in "shut in" pressure is due to wear either on the impellor tips, or wear at the suction so the water from the discharge side of the impellor leaks back around to the suction side. Have a look at it and see if there is a lot of wear. A replacement impellor would be a lot cheaper than a complete pump.

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@ Grumpy:

Thanks for the reply. There is no leak back as I isolated the accumulator and turned off the pump overnight. After 12 hours the pressure was still the same so it is obviously wear or damaged impeller in the pump.
It is going to cost $500 to lift and lower a 20-year old pump. Add a new pump head to the old motor is another $520. For $1600 I can get it all done with a new Gould. However cash is tight so I want to stretch the useful life a little farther.
@LLoyd: I am not missing the point, it is impossible to set the pumptrol cut- in independent of the cut-out. I have studied the design and a softer main spring would probably work. The secondary screw is **only** there to adjust cut off pressure **providing** it is over the 20-psi differential. That smaller post has a step that holds the secondary spring above a threshold of the rising plate being pushed up with the bellows. I could have set the cut-in pressure at 20-psi and then used a spring that went over that step and rested on the rising plate, **then** I could adjust the cut out pressure.
However, yesterday I bought a FURNAS (I use caps as lowercase makes it look like FUMAS (Furnas)) control which is much better designed. It has one screw for adjusting both cut-in and cut-out up or down. It has a second screw that adjusts the cut-out pressure **without affecting the cut-in**. It can range from 10 to 40 psi cut-in with a minimum differential of 7-psi and a max cut-out of 80-psi. Perfect.
Starting at zero pressure, I ran the pump until it showed 20-psi and adjusted the cut-in screw to click in. I then waited until it got to 35-psi and adjusted the cut-out screw for it to click open. Bingo, we have a winner. I will replace the Pumptrol on my other well with a Furnas as it is a much a better design.
I am not too concerned about the start/stops as the 200 gallon accumulator buffers the water nicely. The pump will now run about twice every three days. It runs for about 18 minutes to replenish the accumulator and bring up the pressure. So for the $5 Furnas (used - 3 for $15:)) control, I have extended the life of the pump. I just had a shower and 25-psi is quite adequate.
Dave
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@ Grumpy:

Thanks for the reply. There is no leak back as I isolated the accumulator and turned off the pump overnight. After 12 hours the pressure was still the same so it is obviously wear or damaged impeller in the pump.
It is going to cost $500 to lift and lower a 20-year old pump. Add a new pump head to the old motor is another $520. For $1600 I can get it all done with a new Gould. However cash is tight so I want to stretch the useful life a little farther.
Can't you do it yourself?
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