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PatH25 · Aug 6, 2008, 04:47 PM

I recently replaced a 1/2 horsepower shallow well pump with a 4 gallon pressure tank. The cut in is set at 30 psi and the cut out at 50 psi. The pressure tank is set at 28 psi. When I turn on the pump it runs and builds pressure to 50 psi and cuts out like it should. The system maintains the pressure until I put a demand on it, turning on a faucet. Once a faucet is turned on, say for using a sprinkler or garden house, the pressure drops down to the 30 psi and the pump turns on as it should, however, the pressure continues to drop down on the pressure gauge at the pump to 0 psi. The water continues to flow at the faucet but at a significantly reduced pressure. While the faucet is on and the pump is on the pressure never builds back up to the 50 psi. Once the faucet is shut of the pressure will immediately build back up to the 50 psi and shut off. Is my pump not able to keep up with the demand or is there something else that is keeping the pressure from building up while the pump is running and the faucet is on? Any help is greatly appreciated.

hkstroud · Aug 6, 2008, 05:22 PM

You are correct. The pump can not keep up with the flow at the faucet. If you truly have a pressure tank and not a bladder tank, you only have 1 1/3 gallons of usable water before the pump comes on. If you have a bladder tank you have 2 gallons.

Your pump and tank are way too small for normal residential use. You can compensate for the small pump to some extent by increasing the size of the tank. A 40 gallon bladder tank would give you 20 gallons of water at between the 30 and 50 lb pressure. Enough for one shower. A 60 gallon tank would be better. Forget the sprinkler, pump that size never going to be able to keep up.

albinfla · Aug 6, 2008, 05:56 PM

Harold is right on. At 30-50 psi, a Sta-Rite 1/2 hp pump only puts out between 3.5-6.9 gallons per minute at a 25 foot pumping depth. It puts out a little more at shallower depths. You can test it by seeing if you can regulate the flow so the pump holds constantly at say 30 psi, then see how long it takes to fill a bucket. That way you'll know if you're getting anywhere close to how much you should be out of your pump.

I would absolutely go to the 60-gallon bladder tank. It will give you some cushion so that you can take your shower and run off the tank. Then, it will have recovery time to build back up. It sounds like it will take awhile.

You may also check your suction pipe. It is possible that the foot valve is clogged up with some buildup. If you have sand-points driven down it is not so easy to unclog. I have had success putting muriatic acid down them in absolutely desperate situations. But, it will hurt steel pipes.

I reinforce what Harold said about irrigation. Forget it with that well.
Al

PatH25 · Aug 6, 2008, 06:01 PM

Hi hkstroud, thanks for answering my question. I do have a bladder tank. I only use this pump for doing outside irrigation type work, say using a hose with one sprinkler head at a time so I do not use it for residential faucets or showers, those are hooked to city water supply. So would you say I would be better off getting a bigger pump for this type of use? And if so what size pump would you suggest I use?

albinfla · Aug 6, 2008, 06:35 PM

The type of pump you would use depends on if your well would support it. What type of well do you have?
Al

PatH25 · Aug 6, 2008, 08:19 PM

Al, I have a shallow well, not exactly sure how deep as the well was already in place when I purchased the home. It is a sand-point driven well in the basement of my home that is only used for outside faucets for gardening/sprinkling with one sprinkler head on a garden hose at a time.

albinfla · Aug 7, 2008, 05:16 AM

Pat,
If you only have one sand point, you are not going to get a lot of production out of it. I wouldn't go over a 1/2 hp pump, because you won't get enough water on the suction to feed it. Do the gallon per minute bucket test I spoke of earlier first, and see how much the pump is producing. Then, I can guide you on a couple of ideas to wash back down your well if you need to.
Al

PatH25 · Aug 7, 2008, 10:36 AM

Al, I did the gallon per minute test you suggested. With the pump flow regulated at 30 psi the pump produced 4.3 gpm. My pump is a Wayne 1/2 horsepower shallow well jet pump. I noticed something different with the pump today. When I first checked the pressure gauge before using the pump, it showed a pressure of 44 psi. When I turned on the faucet to begin the gpm test the pressure began to drop as it should, then when it reached the 30 psi cut in point the pump did turn on, however again the pressure dropped to 0 psi like it has been doing, but this time the water stopped flowing for approximately30-60 seconds, then it appeared as though it re-primed itself and began flowing steady again. Once I finished the gpm test, and shut off the faucet the pressure again built back up to 50 psi and the pump cut off as it should. The pressure gauge again is now holding steady at 44 psi. Does this sound like I may have a leak somewhere or a bad check valve or something? What would cause it to lose its prime, yet still show a steady holding pressure of 44 psi? Thanks for the help.

albinfla · Aug 7, 2008, 11:05 AM

Pat,
The gpm is okay. The Wayne pump probably doesn't pump as much as a more quality Sta-Rite, or Goulds. I think you are definitely on track... you probably have a leaky check valve, and you may have some leaks in the well-point pipe. Hopefully there is not a leak in the well point pipe, because there's probably nothing you can do about that.

1- check for suction leaks between the pump suction and the well point. Just use some real sudsy water and see if it sucks it in with the pump on, then shut the pump off and see if it sucks it in back down the well.
2- install a check valve as close to the well point as possible... if possible, point it upwards if it is a spring loaded poppet type. I don't recommend a swing check because they tend to leak. Use a good check valve such as Simmons or preferably Flo-matic.
Al

PatH25 · Aug 7, 2008, 11:19 AM

Al, thanks for the help. I will try and put in a new check valve and look for leaks. I think I may have found a small leak on the point side of the well already.

albinfla · Aug 7, 2008, 11:31 AM

Even the smallest leak up top will allow the water to siphon back down to wherever the water line is in the jet point. If it is tight up top, it can't siphon because there is no air to pull in. It has to pull air or water to fill the pipe. I hope that makes sense. They don't pay me for eloquence or I would probably be in a different profession.
Al