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View Full Version : Why would my pressure drop all the way to zero after the pumps kicks on ?


sjthomas00
Mar 3, 2011, 02:48 PM
We have replaced the foot valve and check valve brand new pump and bladder tank pressure gage and all . We are at a stumbling point

sjthomas00
Mar 4, 2011, 05:33 AM
We have a shallow well pump that is above ground and is set up in house not outside like a lot are...

parttime
Mar 4, 2011, 06:11 AM
sjthomas00, is the check valve in backwards? Just asking.

hkstroud
Mar 4, 2011, 06:35 AM
Is your pump a jet pump or a centrifugal pump? In other words how many pipes go down the well, one or two? Were is the pressure gauge? Is it on the tank or on the piping? If on the piping, is it between the check valve and the tank or is it between the check valve and the pump?

What is the pump switch cut on setting? What pressure did you charge the bladder tank to?

sjthomas00
Mar 4, 2011, 06:36 AM
Parttime no it is not in backwards even has a arrow on it to show which way to put it in . What we don't understand is the pump kicks off at 50psi and kicks on at 30psi when we run water or flush toilets . We can not take a shower or bath cause once pumps kicks apporaxmitly about 1 min the pressure will drop to zero then got to turn water off then it takes about 30 minutes to a hour to build back up . It holds pressure does not keep kicking on and off on its own just when we have water running and after it kicks back on then it goes all the way down . We were wondering if the pump is not big enough along with the bladder tank . We bought it from harborfreight the pump is a 3/4 hp shallow well pump . Does not say jet pump and the bladder tank is only 5gallon tank it is smaller than what was in here .We ran all new pipes and everything beens the house set empty for four years before we bought it and the old pump that was in here was bad from setting to long . We just are a at a stumbling point .

sjthomas00
Mar 4, 2011, 06:43 AM
hkstroud , we only have one line from the well to the pump . The gauge is on hooked in between the tank and motor that's is how it was when we bought the pump and bladder tank . The pump says shallow well does not say jet all it says is shallow well . Here's is a link of the pump and tank you can see a picture of it http://www.harborfreight.com/3-4-quarter-hp-1-inch-cast-iron-shallow-well-pump-2955.html . If it can help any one out . The pressure tank is set at 28 .

sjthomas00
Mar 4, 2011, 06:48 AM
hkstroud , we only have one line from the well to the pump . The gauge is on hooked in between the tank and motor that's is how it was when we bought the pump and bladder tank . The pump says shallow well does not say jet all it says is shallow well . Here's is a link of the pump and tank you can see a picture of it http://www.harborfreight.com/3-4-quarter-hp-1-inch-cast-iron-shallow-well-pump-2955.html . If it can help any one out . The pressure tank is set at 28 .

sjthomas00
Mar 4, 2011, 06:52 AM
Parttime no it is not in backwards even has a arrow on it to show which way to put it in . What we don't understand is the pump kicks off at 50psi and kicks on at 30psi when we run water or flush toilets . We can not take a shower or bath cause once pumps kicks apporaxmitly about 1 min the pressure will drop to zero then got to turn water off then it takes about 30 minutes to a hour to build back up . It holds pressure does not keep kicking on and off on its own just when we have water running and after it kicks back on then it goes all the way down . We were wondering if the pump is not big enough along with the bladder tank . We bought it from harborfreight the pump is a 3/4 hp shallow well pump . Does not say jet pump and the bladder tank is only 5gallon tank it is smaller than what was in here .We ran all new pipes and everything beens the house set empty for four years before we bought it and the old pump that was in here was bad

rjh2o
Mar 4, 2011, 07:17 AM
It sound like the pump is losing its prime. Is the check valve on the incoming line to the pump. If not the pump is losing prime after the bladder tank fills up. The pressure switch may be bad also.
RJ

sjthomas00
Mar 4, 2011, 07:52 AM
The check valve is on the line to the pump and the foot valve is at the end in the well . The thing is that the bladder tank does not fill back up after the pumps kicks back on . We are thinking about taking this one back and buying a jet pump to see if that works

hkstroud
Mar 4, 2011, 08:10 AM
Sorry but I don't think that set up is going to work for you.

First it is a centrifugal pump not a jet. A jet would have two pipes going down the well. I don't see anything that indicates that it is a bladder tank.

The specifications show 898 gallons per minute. That is slightly less than 15 gallons per minute. That sounds like a lot but that is its maximum. Of course we don't know how those specs were developed. If the well is 5 foot deep and the pump is sitting next to it with an open pipe it probably will produce the 15 gpm. If the well is 20 foot deep it will produce a lot less. And I do mean a lot.
Put on a faucet (which usually has a 1/4" internal opening) on the output line and the volume will drop even more. Raise that faucet 20 feet and volume will drop more. The pump must overcome the resistance and pressure created by the faucet, smaller pipes and the elevation.

The tank size is 5 gallons. That doesn't mean it stores 5 gallons of water. If you take a sealed tank and pump water into it, when the tank is 1/3 full of water, the compressed air will have 40 lbs of pressure on the water. When the tank is 2/3 full the air will produce 60 lbs of pressure. So, if your pump switch is set to come on at 40 and go off at 60, you have 1/3 of the tank for usable water. In you case that means you have 1.66 gallons of water before the pump comes on.

If it is taking 30 minutes to pump the tank up to 60 lbs that means the pump is pumping an average of .05 GPM. Remember that as the pressure in the tank builds, the volume of water being pumped is reduced.

When you open a faucet you immediately use the stored water in the tank including the water that is need to create the pressure. The pressure drops to zero or so close that the gauge reads zero.
Then you are depending on the pump to deliver the water. In your circumstance it just can't do it. You didn't say how deep the well is or how far from the house it is. I assume that the pump at the house and the well is some distance away. That is also a factor. Pumps push water far better than they pull water.

Sorry, but the Harbor Freight pump is not going to be adequate to supply all of you water needs. I'm sure it will do what the specifications say it will do but only under the most ideal circumstances, that is, a very shallow well, the pump right at the well and an open discharge pipe.

You will have to open you wallet and get a real well pump.

sjthomas00
Mar 4, 2011, 11:15 AM
Thank you hkstrouds we were thinking it was to small . WE are renturning it and getting a jet pump . Thanks again

jlisenbe
Mar 4, 2011, 12:12 PM
Allow me to give you my thoughts on this problem.

Generally speaking, jet pumps are centrifugal pumps. They have an attached venturi "jet" to create a partial vacuum which allows air pressure to move water up the well pipe. On a pump with one pipe, the venturi is in the pump assembly itself. The downside of that assembly is that it can only draw water from 25' or less. The jet pump with two pipes has the jet in the foot valve in the well and can pump from deeper depths.

I think your small tank is an issue. You turn on water and rather quickly use up your reserve in the tank. The pump kicks in, but I'm going to guess the water level in your well is low enough that the pump struggles to supply more than a relatively small amount of water, which would explain why your system takes so long to recover.

Your pump should be able to supply at least 4 or 5 gallons a minute. To check that, run water until the pump kicks on, then run water from an outdoor faucet into a 5 gallon bucket. See how many gallons you get in a minute. I'm going to guess you are getting next to nothing. So the first step is to check the water depth in your well. If it's in the 25 foot range, then you have found your problem. Then you are, as HK quite correctly pointed out, looking at finding a different arrangement. Personally, I would not even consider a jet pump IF my well was large enough in diameter to put in a submersible pump. If you can put the two pipe arrangement into the well, then you can possibly go with the sub pump. You will be much more satisfied with that arrangement if you can get it to work. A 1/2 horse sub pump will give you more water than you will know what to do with.

You also need a 30 or 40 gallon bladder tank rather than what you currently have. 5 gallon tanks are not designed for what you are doing.

hkstroud
Mar 4, 2011, 02:37 PM
How deep and what kind of well do you have, a dug well (big hole in the ground) or a drilled well (a pipe which is the well casing, usually about 4" in diameter) which you drop the well pipe down?

Not knocking Harbor Freight (I occasionally shop there) but the quality of their merchandise can be lacking. I don't think the power of the motor or size of the of the pump is the issue. It's the precision or quality of the pump itself.

Shop at a merchant that sells regular domestic well pumps and tanks. If you are in a rural area even Lowe's may have something satisfactory.

Google well pumps and do some reading. Check out the link below. Not necessarily recommending Sears but note the specs give the volume at different well depths at 40 lbs of pressure. That's the kind of information you need.

As jlisenbe points out get the largest bladder tank you can fit into your space. The life of the pump is relative to the number of times it starts and stops. The larger the tank the less frequently it has to come on.

http://www.sears.com/shc/s/p_10153_12605_08302518000P?i_cntr=1299273526170

sjthomas00
Mar 8, 2011, 06:25 AM
Okay we went to and got a jet pump that is what the people that lived here before us had . Took the other one back . We have a big 4500 gallon concret holding tank for our water . We half to have our water hauled. . In the tank it has one line that has the foot valve at the end of it that is the main line that runs into our house and inside the main line inside the house we have the check valve then it goes to the pump . Then from the pump to the bladder tank (which we have is a craftsman 42 gallon) ,then to the house or might not be explaining it to well.. But with all this new stuff no leaks still having the same problem but the pump won't kick off now . We are getting ready to change the pressure switch to see if that is it . And hoping it will hold pressure and will kick off after pressure is build back up .

sjthomas00
Mar 8, 2011, 06:27 AM
Thank you I still am having problems with new stuff . I posted more info as an answer on this

sjthomas00
Mar 8, 2011, 06:32 AM
And we got the pump from Lowe's this time

hkstroud
Mar 8, 2011, 07:03 AM
OK, so you are pumping out of a holding tank? Certainly shouldn't be having these kinds of problems.

What is the elevation of the tank relative to the house.

What did you set the pressure switch to?

What you pressure did you charge the bladder tank to?

sjthomas00
Mar 8, 2011, 10:48 AM
The pipe that runs down from the house to the tank is only about 6 1/2 ft long maybe 7 the most and the pipe inside the house from the tank to the pump is only another 4 1/2 ft . The pressure switch is 20/40 and the bladder is right at 18 . The pump is kicking on and off like it should just when we turn water on then pump kicks on it loses pressure

sjthomas00
Mar 8, 2011, 10:49 AM
The pipe that runs down from the house to the tank is only about 6 1/2 ft long maybe 7 the most and the pipe inside the house from the tank to the pump is only another 4 1/2 ft . The pressure switch is 20/40 and the bladder is right at 18 . The pump is kicking on and off like it should just when we turn water on then pump kicks on it loses pressure and the holding is maybe nine to 8ft deep it is more wide than anything .

jlisenbe
Mar 8, 2011, 05:06 PM
When you say "it loses pressure", do you mean for a second or two, or for a much longer period? With basically no elevation to pump from, your pump should be giving you enough water for two houses. If you are still using the 5 gallon pressure tank, then this is what you should see. When you use water, the pressure will drop rather rapidly from 40 to 20, maybe measured in seconds. When the pump cuts back on, then it should be able to pump pressure back to 40 in fairly short order. If pressure drops at all, it should be very brief, a second or two. Is that what you are seeing, or have you changed the tank for a larger one?

sjthomas00
Mar 8, 2011, 06:00 PM
WE got a bigger tank it is 42 gallon and a different pump . When it drops is very shortly after pump kicks on after have water running for about a min to two . The pressure will drop completely then it builds back up and cuts off about five minutes ten minutes tops . WE found a little leak in the line that comes from the top of the pump that runs to the main line of the house . Very very small leak that only drips when water is off . Could that have something to do with it ?

hkstroud
Mar 8, 2011, 06:01 PM
Let's recap everything.

You have a holding tank 7 or 8 feet out side the home approximately 8 foot deep.
You have a jet pump 4 foot inside the home. A jet pump with two pipes to the holding tank with a foot valve. You also have a check valve inside.

What size are the pipes to the holding tank and what size is the pipe to the bladder tank.

Pump pressure switch is set to 20/40. Bladder tank is was pressurized to 18 lbs.

The tank was empty when you pressurized it, wasn't it?

If you press the valve stem now, do you get air or do you get water coming out?

Not sure about your last statement. I think what you are saying is the pump comes on and off properly when not water is being used and pressure is maintained in the tank.

When a faucet is opened, the pressure drops rapidly but only momentarily until the pump comes on and gets up to speed.

Is my understanding correct?

Sorry about all the questions, please remember I can't see from my house to yours.

PS
Please use the "Answer This Question" block only to respond. Do not use the comments feature. Your responses are showing up twice.

sjthomas00
Mar 8, 2011, 06:01 PM
jlisenbe WE got a bigger tank it is 42 gallon and a different pump . When it drops is very shortly after pump kicks on after have water running for about a min to two . The pressure will drop completely then it builds back up and cuts off about five minutes ten minutes tops . WE found a little leak in the line that comes from the top of the pump that runs to the main line of the house . Very very small leak that only drips when water is off . Could that have something to do with it ? Please excuse me how I am answering or replying still trying to learn the sight

sjthomas00
Mar 8, 2011, 06:06 PM
hkstroud First thank you for telling me how to answer propley . Yes to all but the bladder tank it is good . And when we first check it it was empty . But we have found a very tiny leak in the line from the pump to the main line inside the house . Could this have something to do with it ?

sjthomas00
Mar 8, 2011, 06:08 PM
And when it drops when the pump kicks on it goes completely to zero then I turn faucet off it build back up

hkstroud
Mar 8, 2011, 06:32 PM
A small leak in the line between the holding tank and the pump might have something to do with it if the leak is sufficient for the pump to loose its prime. Somehow right now I don't think that's the problem.

Right now I seem to be focused on the bladder tank. Sound like some kind of delay or restriction between the pump and the tank. What size pipe between the pump and the bladder tank?

When you set the system up, you pressurized the bladder tank to 18 lbs and then turned the pump on, right? In other words, the tank was completely empty of water when you pressurized it.

Most people prefer a little higher pressure than you are currently using. Most people prefer a 30/50 or a 40/60 setting. You might want to increase the settings. A higher setting will give you more storage in the tank.

sjthomas00
Mar 8, 2011, 06:47 PM
hkstroud the size pipe that we got between the pump and tank is 3/4" cpvc and yes the tank was empty . We will try to set pressure higher like the 30/50 and see what that does . Now I should have have right at 28 maybe a little higher in the tank right ? When I adjust the settings

hkstroud
Mar 8, 2011, 07:11 PM
Remove switch cover and tighten nut on large spring. Pump should come on. Adjust slowly. Keep tightening until desire cut off pressure is reached.

Turn pump off and drain tank. Disconnect piping to drain if you don't have a drain valve. Pressurize tank to two pounds below cut on pressure. Cut in pressure will be 20 pounds below cut off pressure.

Is 3/4" size of the output of the pump or did you bush it down? Would have expected a little larger size but it depends on the size of the pump.