my tank seems to be holding air, I drained the tank, checked the psi with all the water out, and after a few days it still held pressure. had somebody check what they called the capacitor, on diagrams online it looks like its actually called a control box, and the voltage isn't right. he said theres resistance from somewhere...what causes that?

 

in a nut shell this is whats happenening... sometimes the tank works fine, sometimes the water comes on for a second, looses all pressure and stops working for an amount of time and then comes back on for a few, then eventually goes back out. we called one company to check it and he replaced the capacitor and switch and told us the tank is going out. after a day the water stoped working again, called him up and he said its the tank and he wont replace the capacitor he just installed unless we replace the tank. I had a friend come check it out, he said the capacitor is going out already, he thought there was a resistance problem. so I called another company for a second opinion, along with that I reached out to people on this forum. and all of you said the same thing, check the tank. so I drained the tank the tank, checked the psi, it was low 30's, my tank is supposed to be around 40, so I added a little pressure. flipped the power back on, and the water worked for a few then encountered the same problem. then I called a third company. the next day, told him whats going on, that the tank seems to be holden air, so he checked the capacitor with the ohm meter, showed me that there is indeed resistance, and said its most likely the pump motor. he said that something is stopping the control switch from doing its job. that's all the info I have. I wish I was more knowledgable about this kind of thing to help you help me lol, but that's all I know...does this sound correct, or are there other causes for this resistance...any help is appreciated

 

The pressure tank does make the pump or the system work or not work. It just smooths out the water flow and prevents the pump from turning on/off too frequently.

I am going to assume that the people checking the capacitor are checking it properly. A capacitor really does not show resistance. It will show a resistance value for a period of time as it's building a charge but once it's reached capacity it's resistance should fall to almost zero. A capacitor should be checked for capacitance (not resistance), the measure of how much current it can hold. Capacitors can go bad by loosing some of their capacitance. Sorta like a refrigerator that still gets cool but not as cold as it used to and you know it's getting ready to die. I would assume it's good since you said it has already been replaced with a new one.

Has anyone checked the resistance values across the various combination of wires leading to the well & pump?

 

High voltage..... Use caution when working on electrical items...

How to check pump motor...windings..

TESTING SUBMERSIBLE PUMP MOTORS

How to check control box.

TESTING SUBMERSIBLE PUMP CONTROL BOX

Also you need to adjust the air with the tank empty.......If your not taking all water pressure off the tank then the psi will not be set correctly... Shut off power to the pump, close a valve after the tank, drain the tank of all water, then adjust air... Air should be about 5 psi below where the pump kicks on...

So if kicks on at 40 psi...set for 35psi....Too much air will cause loss of water for a few seconds before the pump catches up.....

 

I haven't checked the control box/capacitor myself yet, but looking at that link that appears to be the test the repairman did when he came out here. I also haven't checked the pump motor. but I have been checking the tank regularly to make sure its holding air. I did what you said and the psi is fine, but the tank has no water in it, it wont fill back up

 

and I also hear the pump kicking on and off every 5 minutes or so, even if nobody is using the water