I have a rain catch system with a 1000 gallon above ground tank. I have it piped out a couple of feet to a 1/2 HP shallow well pump, it feeds through a UV/sediment/charcoal filter trio then into the bunkhouse. It has a vertical pressure tank and a check valve. The first pump that got installed never would cut off after pressuring up. Replaced it and got the next one adjusted to cut off at 50 psi and it worked fine until it froze and cracked the housing. Replaced that one and the new one will come on, pressure up then just click on and off continuously. I adjusted the cutoff and cut-on/cutoff nuts and it will cutoff, then kick on for a second, then pause a few seconds, them kick on again. Underneath the contacts you can see a flap that slowly depresses then the contacts trip. I'm assuming that is the pressure switch? No leaks anywhere. Could it be pressuring back into the tank? I can't figure the dang thing out.

Do you have a check valve on the suction line to the pump? Sounds like when it cuts off, it bleeds back down the suction line, sees low pressure and starts the pump, sees high pressure and cuts off and so on.

If your supply tank is full there may be enough static pressure from the weight of the water to hold the pressure in the pump, however if it is low, it could just bleed back into the tank.

No, there isn't a check valve but the tank has 1000 gallons in it.
I think I'll install a check valve this weekend if it actually gets above freezing!

I was having the same issue with this setup, the check valve solved the problems.

Side Note:
If you install valves on both sides of the check valve and use union fittings, then you can easily take it off when you leave and not worry about it freezing and breaking.........I figured that out after the first winter.

Is the tank in the open or covered up?

Yes. I have a diagram somewhere that I drew up but can't find it at the moment. You need a check valve to keep the main line pressurized and you need a pressure sensor on the pressurized tank that will control the on off of your pump. You can get an adjustable one from grainger for 20-60 psi I think is where I found it. For like $30

I had a better diagram that had how I was doing mine but it's packed up at the moment.

The tank is in the open but the pump/pressure tank/filters are all enclosed.

If that is the case then you can get a small electric heater with a thermostat, set it low as it will go, plug it in and forget about frozen pipes, pumps, etc.

I have a thermo Cube with 2 heat lamps plugged in and it works great. Comes on at 35 and turns off at 45.
Thermo Cube

Just thinking outside the box.....

Ran into a similar situation after replumbing the water line to the house. Pressure switch had to be within about a foot or so from the pressure tank. Also a ruptured or leaking bladder in the tank (if your's has one) will also cause the pump to cycle on & off.

Oh yeah.....Roger on the check valve!

Good Luck!

leak of some kind er a bad switch

How much air pressure have you got in the vertical pressure tank? Sounds like it's waterlogged.

Like HnF said, if it has a bladder it could be ruptured. If not, there should be a Schroeder valve where you can add air.

Checked the pressure in the pressure tank and it's at 35 psi. Replaced the pressure gauge and got the two pressure cuton-off nuts adjusted. Now it will only click on for less than a second about every 10-15 minutes. It's almost there.

Got this fixed- I hope. Replaced the pressure switch and, after research, found out the pressure in the pressure tank bladder needs to be 2 psi less than what pressure you want to maintain. So inflated the bladder to 38 psi, set the pump to 40 psi, so far so good.

Outstanding......