I have a pump question.....

This is not my first rodeo, I've worked on many pumps and rebuilt many. I've even put in wells and pumps.....





I don't know how old the pipe and sand point is. I would say my grandfather put it in back in the 60s. I know it wasn't touched from 1990 to about 5 years ago (city water was put in). I removed all the broken and old junk when we bought the house. I hooked up a small used jet pump to the sand point and ran 100 feet of black plastic pipe out to the garden. It has a very small air tank, and it worked great for watering the garden. last spring the pump had some issues with holding pressure and cycling a lot. I figured we were due for new pump. I replaced it completely.


The new pump and air tank is set up to turn on at about 40 psi and shut off at 60 psi. The air tank has roughly 55 psi in it. I worked great. Pump would run, shut off, had enough pressure for over 20 to 30 seconds pressure then turn back on. It's been working great this spring till recently. I am now back to the fast cycling, on, off, on, off. I can not find any reason it's doing this. The only thing i haven't looked at is the check valve on the well, I'm suspecting that is my problem.

Has anyone delt with this issue?????

All the shallow wells with a bladder tank I have put in used or repaired, has a air pressure of 2 psi below cut in pressure of pump. That is without and water pressure and pump off, meaning shut off pump turn spigot on till no water comes out and set pressure. Fast cycling to me means bladder issue. Add some air to Schrader valve, if pump stops short cycling the bladder is leaking. Or if water comes out of Schrader valve.

Kill the breaker and bleed the water pressure to zero. Use a pressure gauge on the schrader valve on the tank to see what the air pressure is in the tank. The pressure should be 2 or 3 psi below the cut in pressure of your switch. You said your cut in pressure is 40, so your tank should read 37 or 38 psi, if low add air.

I wonder if your expansion tank is too small.

Both my pumps have a check valve built into the pump casing just inside the port where the suction pipe connects.
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What Feedingground said about being water logged. Does pump run ok when a faucet is wide open or does it still kick on an off.

If you unplug pump and open an outlet run it dry then plug back up and before it has time to even fill up it clicks on and off then, As a last resort (I know this doesn't make sense since its a new like pump) but the little 1/8 line to the shutoff switch can be stopped up with rust or dirt and gets air instead of water under the little rubber diaphragm in switch. You can take apart and clean. But if its some china special like a HarborFreight then the first time it does that I put a Square-D switch on it. I also change the plastic 1/8 hose to copper. 1/8 or 1/4 etc.

Please let us know what it is when you get it fixed.

Sounds like a check valve with submersibles you can test the electrical to see if the motor is spinning backwards when it shuts off the motor can turn fast enough to create electricity. With a jet pump if you have a ball valve with nothing connected to it on the pressure side you can have someone pull the power when pressure is reached and open the valve and put hand over it like a hydrant and if its going back it will create suction like a hydrant does, this is assuming you don’t have water leaving the pressure side of the pump going outside somewhere.

definately check on the check valve -- turn the pump off close the discharge valve and see if the guage drops quickly or slowly -- or add a check valve up top before the pressure tank on the discharge side of the pump. this can keep you from having to pull the tubes. whichever is easiest-- if you add a check valve up top and the bottom one is leaking be prepared for priming issues.--davem

it can definately be a bad bladder tank but this will help you troubleshoot

Thanks. Sometimes you are so close to the problem you can't see it.
I incorrectly set the air pressure in the tank. I set it to just under the cut off, and it should have been just under the turn on pressure. I did this a few weeks ago when I thought it was low.


The check valve is good. The pump is working much better, still not what it was. Tomorrow I will tear apart the plastic tube to the pressure switch, that may have sediment in it. I shouldn't need to pump for a few days since we got 2.25 inches of rain today

Ants in pressure switch can cause a problem with shorts.

If its not still snapping on and off maybe the tube don't need cleaning, but if you do I always try to get the switch up above the pump so when the water settles in the tube the rust and dirt goes down to the pump and not up in the diaphragm in the switch. The one I have now I added a longer tube and have it tied to the wall up above the pump.

I designed and inspected hundreds of livestock watering systems by private owners and contractors for USDA Standards and Specifications. Pressure tank size (20-30-40-? gal) should match water output of pump, pipe diameter and psi (switch) requirements. When set correctly the pressure tank should provide approx. 2 minutes of flow before the pump kicks in (hence the 2-3 psi difference). Once the pressure reaches the kick out limit (pump shuts off), it should take about 2 minutes for the pressure tank to drain/push water and then the kick in pressure is reached. The cycling as you stated is where the heat builds up and ruins the pump so addressing it is the right thing and a waterlogged tank is always a good start. I have seen all types of home-made pressure tanks used and if you can situate the tank at the highest location on the pipeline (and the tank is big enough) you may be able to use it even if the bladder is gone (air is compressible - liquid is not - law of hydraulics). Unfortunately your tank may not be able to be located on a high spot close to the pump so a bladder/tank replacement may be your only option. ..... the mike

It's a new pressure tank. No water in it at all. I assume it is 14 gallons because of the model number. Tank is higher than the pump. After looking at it last night I set the tank at 28 psi, turn on at 30, cut off at 50 psi. There is only 15 to 20 seconds between cycles.

Mine was doing the same thing. there was no air in the tank. Put the air in and it worked fine.

When the pump cuts off, what is your gauge telling you, is the pressure dropping? If pressure is dropping cut off output valve, if pressure continues to drop you have a leak in the well, or bad foot valve that is leaking down.

When the pump shuts off and the outside valves are closed it holds pressure. No leaks

I believe expansion tank only has 1/3 of its capacity for usable water so only good for about 4.6 gallons per minute. What’s the flow rate of the pump.

If you are using a 30 / 50 switch and a 5 gpm pump your tank is probably the culprit and its too small. No leaks in the system when kick-out pressure is reached as you stated. The Montana Livestock Watering Facility Handbook will tell you the exact size but from experience, a 30 Gal. size sounds in order. That 2 minute (or longer) drain time before kick-in is reached is what you want. Draining 20 psi off the system in 20 seconds and then recharging the kick-out psi sure sounds like the advice everyone is giving (waterlogged and/or too small of a tank). .... the mike

If you open the valve and it starts cycling, the gauge should reflect pressure drop and then pressure rise until the switch cuts off, if this is correct you have water going somewhere downstream of the cutoff valve.