Shallow Well Pump Problems

[R Bishop]

I have been having alot of problems with my shallow well jet pump system.This system is probably 20 years old and I have had pressure problems for a long time. The other day it started very short cycling so I thought it was the pressure switch and went and bought a new one pre-set at 30/50 and put it on and it would not kick off so I adjusted on it and could not get it right, it would go from very short cycling to sticking on. I discovered that I had a hole in my pressure tank bladder and replaced the tank with a new tank pre-charged at 28#. I checked the pressure with a tire gauge and it is at 28#.Well as i said I had adjusted on the pressure switch so I have had to work on it agian. The problem is that the pump goes straight from very short cycling (1 second on to 1 second off) to being stuck on. I do not have a gauge to check the pressure it runs when running but it does pump with a fair amount of pressure but I would guess it not to be over my 30# kick on point. The system will not build up any pressure. I think that my old pump is wore out and will not build up any pressure. I am just a poor boy and need to know for sure what is wrong before I go and buy a new pump. Any help would be greatly appricaited. Any suggestions on what I can do or need to check before I have to go buy a new pump would really help.

[Pumpman]

Shallow well jet pumps have an ejector that is usually builtin in the pump just in front of the impeller. The ejector has a nozzle and a venturi tube in it. The job of the nozzle and venturi is to direct water flow into the eye of the impeller (it's an engineered thing and is somewhat more complicated than what I've explained). Sometimes that nozzle will get plugged up with rust, scale, etc., and the result is that the pump won't build pressure. Others causes for lack of pressure are excessive impeller wear, partially plugged impeller vanes, and not enough of a water supply.
Among reasons for short cycling are too small of discharge piping, too many elbows and curves in the discharge line, and as you've discovered, a bad bladder tank.
Ron

[R Bishop]

Thanks very much for your help Ron. After fighting this thing most of the last two days I went and bought a new pump and finally have it all together. I have better water pressure than I have ever in this house. Thanks agian. I am sure that my pump was over 20 years old and was just plain wore out. Randy