My pumptrol pressure switch 9013FSG2J21 is set at 75 psi cut off and 45 psi cut on. When opening a 1/2 inch spigot and allowing water to flow freely my water pressure falls from 75 psi to 45 psi, the motor turns on and the pressure begins to build and will build all the way back up to 75 psi, the motor cuts off, then the pressure falls to 45 psi once more. This cycle continues as long as the valve remains open. Varying the opening of the valve (half shut, quarter shut) doesn't matter the cycle continues. Is this normal operation?
TG

Yes, this is normal operation. Only thing that's not quite normal, is the 30 pound differntial. Usually there is a preset 20lbs diff. 75 is a little high, but its not out of range. I would adjust the switch to cut in at 40 and out at 60. However, if you pump is keeping up with the demand, you can set it up a litte higher if you like. Just don't ever set the cut out over 80(and that's pushing it). If you are happy with the water pressure as is, it will be just fine, but if you can get the diff between cut-in, and cut-out to 20lbs, you will not notice the difference nearly as much at the fixtures when pump kicks on and off.

Thank you, for your response and additional information.

My current installation includes a 1 1/2 hp motor (in a deep, 140 ft. well)my storage tank is a 20 gal steel with a bladder charged to 28 psi. Will a larger 80 gal tank cause the fluctuatio

Tony, with a horse and a half only 140' down, you should be getting all the water in the world. With only a 20 gallon pressure tank, I would think your pump cycles are rather short. You really need to be able to get at least 5 or 6 gallons of drawdown (starting at, for you, 70#), until the pump cuts back on at 45#. An 80 gallon tank would definitely be a step up. MyGirlsDad gave good advice about bringing the interval between cutting in/out to 20#.

Thank you for the additional information. Changing to a larger tank and resetting the pressure limits will soon be completed.

If you will, please share your background of expertise in this subject.

Tony

If you have galvanized pressure tank this sounds like a water logged tank. If you have a bladder type tank, this sounds like a ruptured bladder.

Edit.
I see you say you have a 20 gal bladder tank pressurized to 28 lbs. Your cut in pressure is set to 40 lbs. Tank should be pressurized to 2 lbs below the cut in pressure. Either pressurize tank to 38 lbs or lower cut in pressure to 30 lbs.
The present settings would give the symptoms of a water logged tank.

Thank you for your response and information.

When I think of something being water logged, I think of a piece of wood soaking up enough water to cause it to sink to the bottom of a water filled container. Please explain to me what a water logged

Tony, you asked this question in your original question: "Is this normal operation?". The answer to your question is: yes. However, bear these things in mind:

1. You want the cycle between turning on and turning off to be a llooonnngggg one. Your pump works best when it is allowed to run a longer period after starting up.
2. A larger tank will help point #1 a great deal.
3. You are cutting off at 75# which is pretty high. As mentioned before, off at 60 and on at 40 is a good setting. I'll give a link at the end of how to do that.
4. Set your new tank pressure at 2# below whatever cut in pressure you will use. If it will be 40#, then fill the tank to 38# at the little valve on top before you install it.
5. Installation is not difficult if you have some experience with plumbing. You can probably reuse the T fitting that's already on the old tank. I'll give a like below for that as well.
6. Do let us know how it all resolves.

How to adjust water pump pressure, pump cut-on pressure and pump cut-off pressure - private pump and well system do-it-yourself repairs

WikiAnswers - How do you replace a pressure tank and possibly the tank tee fitting

Tank Tee-Long Brass - FP78-7LF at The Home Depot

Galvanized pressure tank, no bladder.

You pump water into a sealed tank, (empty except for air), when the tank is 1/3 filled with water the compressed air will exert 40lbs of pressure on the water. When the tank is 2/3 filled with water the compressed air will exert 60 lbs of pressure on the water.

That basically is how a galvanized pressure tank works. However, over time the air in the tank is absorbed by the water passing through it. When all or most of the air is absorbed you don't have any air left to compress. You cannot compress water. As the volume of air is reduced it takes less of a change in the volume of water to affect the same pressure change.

Let us say that your tank (60 gallons) has no, or almost no air trapped in the top. Your pump comes on at 40 lbs and pumps one gallon of water, the pressure goes up to 60 lbs. You let out one gallon of water and the pressure drops to 40 lbs.

Your tank is said to be "water logged".

Bladder tanks provide a rubber membrane between the water and the air. Therefore, the air is not absorbed by the water. Bladder tanks also permit you to pressurize the tank. This increases the usable volume of the tank. Note that the water in the first third of the pressure tank is not usable. It is there only to pressurize the tank to the minimum pressure. The final third of the tank is to store the required volume of air. The usable capacity of a pressure tank is 1/3 its total volume.

Note also that when the volume of water went from 1/3 to 2/3 full, that reduce the volume of air, already compressed to 40 lbs, by 50%.

Therefore, if you pressurize a tank to 40 lbs of air pressure and then fill it to 50 % capacity with water, the compressed air will exert 60 lbs of pressure on the water.

The bladder does two things. It keeps the air and water masses separate so the air is not absorbed by the water and prevents the tank from becoming water logged. It also prevents the air from escaping should the water level drop below the output pipeing.

Because you start with a pressurized tank, you get to use 50% of the tank volume as usable water storage, as opposed to the 33.33% of the pressure tank.

Thank you very much, excellent explanation.

Tony

Installed larger tank (50 gal w bladder) set switch on at 40 off at 60, bladder charged to 38 psi. On/off cycle time is just under 3 min with 1/2" spigot 1/2 open. Thanks for your participation.

Tony

Installed larger tank (50 gal w bladder) set switch on at 40 off at 60, bladder charged to 38 psi. On/off cycle time is just under 3 min with 1/2" spigot 1/2 open. Thanks for your participation.

Tony

Installed larger tank (50 gal w bladder) set switch on at 40 off at 60, bladder charged to 38 psi. On/off cycle time is just under 3 min with 1/2" spigot 1/2 open. Thanks for your participation.

Tony