When I watch the pressure gauge next to pressure switch, I looks like it's kicking in abut 40 PSI and kicking off around 56 PSI .

How can I check the actual pressures at which the switch turns on and turns off?

It looks like there are two adjustment points; one with a large spring and a long adjustment shaft and one with a much smaller spring. How do I use these to change the pressure on and off points (I'd like to set to 30-50 from 40-56)

Hey Curt,

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How can I check the actual pressures at which the switch turns on and turns off?

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Purchase a Hose bib Pressure gage,(see image) and check your pressure settings through that.
To set your cut in and cut out points on your control box First turnoff the power at the breaker box, then pull the cover off the pressure switch and you will see two spring loaded bolts secured with nylon nuts.( Click on the attachment below) One tall, one short. To increase the cut in pressure, turn the nut on the tall bolt down. To increase the cut out pressure,(that's the one that will give you more pressure) turn the nut on the short bolt down.
Good luck, Tom

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Originally Posted by curtisller

When I watch the pressure gauge next to pressure switch, I looks like it's kicking in abut 40 PSI and kicking off around 56 PSI .

How can I check the actual pressures at which the switch turns on and turns off?

It looks like there are two adjustment points; one with a large spring and a long adjustment shaft and one with a much smaller spring. How do I use these to change the pressure on and off points (I'd like to set to 30-50 from 40-56)

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To me it seems like you looked at a pressure switch to find the 40-56 numbers that you quoted. Why can't you use the same gauge to watch where the low pressure number is when the pump switches on? Then you keep adjusting till you get to that point. I myself would rather have the low pressure a little higher than the 30 pounds that you mentioned.

speedball1
Is trial and error the only way to know how far to turn the nuts to get the desired pressure?
My pressure switch looks like the one in your attachment. About how many nut revolutions will I need to get a 10 PSI drop in the cut on pressure; and how about the cut off pressure? It doesn’t look to me like there's too far I can turn the cut out pressure nut before it would come off.

Letmetellu
I'm reading the pressures off a pressure gauge next to the pressure switch. I'm not sure how accurate the gauge is and it sticks some. I can tap it and see what it says.
Why would you set the low end pressure higher than 30 PSI?

Why does everything I read have a 20# differential between the high and low pressures anyway?

Turn off pump.
Open faucet and reduce pressure to 50#. Unscrew cut out pressure adjustment until relay clicks.

Open faucet and empt tank. If tank has been correctly pressurized, pressure will not drop below 38#. Using air valve release pressure to 30#. Unscrew cut in pressure until relay clicks. Reduce air pressure to 28#.

Turn on pump and verify settings. If you wish you may now fine tune settings.

Tank should have an air charge of 2# below cut in pressure.

Why the 20# differential? That minimizes the variance in water pressure you experience.

You will likely need to tighten the short screw by about 3 full turns to get a 20 psi differential.

You will likely need to loosen the tall screw about 2-1/2 turns to adjust both cut-in and cut-out. One turn equals about 4psi on most switches.

You will have to tweak it a little, but that should get you close. Make sure you follow instructions above and adjust the bladder tank to 28 after you set your switch to come on at 30. If you don't it will ruin your bladder tank!
Al

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speedball1
Is trial and error the only way to know how far to turn the nuts to get the desired pressure?
My pressure switch looks like the one in your attachment. About how many nut revolutions will I need to get a 10 PSI drop in the cut on pressure; and how about the cut off pressure? It doesn't look to me like there's too far I can turn the cut out pressure nut before it would come off.

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As Al explained, One turn equals about 4psi on most switches.
If you have to tap your gage to get a reading then I would repolace the gage.
Good luck, Tom

hkstroud:
Thanks, your procedure makes sense to me.
I don’t understand why you say:
I need to “UNSCREW cut out pressure adjustment until relay clicks.” It looks to me like there's only about 1½ to 2 turns of exposed thread on the small screw anyway.
When Albinfla says:
“You will likely need to TIGHTEN the short screw by about 3 full turns to get a 20 PSI differential.”

How does differential pressure come into play?

I know it's confusing. I used to scratch my head when I first got in the water treatment business 20 years ago. That is why I would just adjust trial and error until I got it right. I still have to do that a little, since the 4psi is only approximate, not exact.

Unscrewing the tall screw moves both the pressure that the pump comes on at and the psi that the pump shuts off at in equal increments. In other words, if your pump is operating at 30/50, and you tighten down the screw 2-1/2 turns, you should have 40/60.

Adjusting the short screw changes the differential. If you loosen it, you can achieve 15psi differential, ex. 35/50. If you tighten it, you can achieve 25psi differential, ex. 35/60.

Hopefully that helps. If you are too confused after my lame attempt to explain it, go to the local hardware or building supply and buy another switch. You can buy them preset to 30/50, or 40/60. They are usually less than $20.

Good Luck,
Al

You said you want to lower the pressures, albinfla gave you a hypothetical "if you want to increase your pressure". What you are doing of course, is increasing or decreasing the tension on the switch spring. Like most things "Righty tighty, lefty loosey"

Screw or unscrew to lower the pressure.
What I think has happened of course, is that you tried to adjust the tank pressure and now have a tank full of air at about 55 lbs. Since the switch thinks the tank is full it turns the pump as soon as you pump the least bit of water. The water and the air are separated by the bladder. Only thing that makes sense to me.

The important thing is to pressurize the tank (empty) to 2 lbs below cut-in pressure.

Hkstroud;

I got into this mess because I decided to water my garden (it seemed pretty harmless at the time :-)
While I had water going to my garden, I realized my pump was going on and off way too fast (maybe 20 second cycle time!). I'd seen this once before, the man that came out to fix it told me the air pressure in my pressure tank was too low. It was low again; about 8 PSI! I realized while adding air to the tank with my underpowered battery operated compressor that I really didn’t really need 40 PSI anywhere in my house, 30 would be sufficient.

I pulled the cover off the pressure switch and watched it work for awhile and couldn’t figure what the two screws did. That’s how I ended up here.

I'm now close to where I think I need to be.
Per letmetellu’s suggestion, I decided to try for 35-55 instead of 30-50
First I loosened the tall screw about 1½ turns. The pump turns on at about 35 and off at about 50.
Next, I tightened the short screw about 1¾ turns. The pump turns on at about 35 and off at about 55. BINGO!

***I still have a question about my high pressure. 55 is the static pressure after the pump turns off. The dynamic pressure just before the pump turns off is probably 58 or 59 PSI. Should I be targeting the static or the dynamic pressure on the high end?

By the way, I'm still adding air to the pressure tank with my underpowered battery operated compressor. I'm at 28 PSI heading to 33 when the battery recharges (again).

I think you got it. Congrats. The 58-59 thing is probably just needle fluxation or water turblance. You didn't pay a whole lot for that gauge. This isn't your blood pressure we are are measuring, (that's probably off the charts by now).

If you are watering you garden and the pump cycles to often (and that's not good), you must be using a hose. Your pump is able to pump more water than can come out the hose. Therefore it builds the pressure in the tank as well as providing water for the hose. Most people try to set up an irrigation or sprinkler system and the well and pump can't provide enough water at the required pressure because they have too many heads. You can prevent the short cycling of the pump by adding additional hoses or heads and then regulating the flow such that pump does not reach the cut off pressure.

Curtisller, we're glad you got it. Good advice Harold. It is better for the pump to run constantly than to cycle frequently. By adding another hose or 2, you can prevent the pump from shutting off at the top end.

I have replaced many pressure switches, and control boxes over the years because the pump was short-cycling. You already did the right things by adjusting the air in your bladder tank, and adjusting a 20psi differential on your pressure switch.

Al

***I still have a question about my high pressure. 56 is the static pressure after the pump turns off. The dynamic pressure just before the pump turns off is probably 58 or 59 PSI. Should I be targeting the static or the dynamic pressure on the high end?

Hkstroud;

I got into this mess because I decided to water my garden (it seemed pretty harmless at the time :-)

While I had water going to my garden, I realized my pump was going on and off way too fast (maybe 20 second cycle time!). I'd seen this once before, the man that came out to fix it told me the air pressure in my pressure tank was too low. It was low again; about 8 PSI! I realized while adding air to the tank with my underpowered battery operated compressor that I really didn’t really need 40 PSI anywhere in my house, 30 would be sufficient.
I pulled the cover off the pressure switch and watched it work for awhile and couldn’t figure what the two screws did. That’s how I ended up here.

I'm now close to where I think I need to be.

Per letmetellu’s suggestion, I decided to try for 35-55 instead of 30-50

First I loosened the tall screw about 1½ turns. The pump turns on at about 35 and off at about 50.

Next, I tightened the short screw about 1¾ turns. The pump turns on at about 35 and off at about 55. BINGO!

***I still have a question about my high pressure. 55 is the static pressure after the pump turns off. The dynamic pressure just before the pump turns off is probably 58 or 59 PSI. Should I be targeting the static or the dynamic pressure on the high end?

By the way, I'm still adding air to the pressure tank with my underpowered battery operated compressor. I'm at 28 PSI heading to 33 when the battery recharges (again).