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How to prime the well pump & how to diagnose & fix repeated loss of well pump prime: this article describes how to prime a water pump to restore water pressure to a building. Page top sketch courtesy of Carson Dunlop Associates.
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First Let's Correctly Identify The Type of Water Delivery Problem You've Got
Before we get into details about how to prime the well pump, let's make sure we're tackling the correct problem:
If your water pump is a two-line jet pump and if it's running but there is no water delivered to the building, the problem could be that the pump has lost its prime. This pump needs to send water down into the well (and through a special valve at the end of the water pickup-pipe in the well) in order to bring water back to the building.
See WATER PRESSURE LOSS DIAGNOSIS & REPAIR for help in determining why you have no water or no water pressure in a building. If the diagnosis determines that you need to re-prime the water pump, the instructions are provided in this article.
If your water pump is a submersible unit the pump is located down in the well itself. In this case if you have not got water pressure, the problem may be with the pump or the well itself, but it's not a loss of prime - submersible water pumps are self-priming.
If your water pump is a one-line jet pump, it is sucking water from a shallow well; you probably don't need to do so, but the instructions below show how to prime the well pump and they should work equally well for either a one-line jet pump or a two line jet pump.
If your water pump keeps losing prime, a shallow well jet pump well line could have a bad foot valve (in the well) and so be losing prime. A leak in the well line can also lead to loss of prime. If priming the well water pump using one of our methods shown below seems to fix the problem but soon the well pump loses prime again, your plumber will want to check for a bad foot valve in the well or a leak in the well piping between the well and the building. See Repeated Loss of Pump Prime.
If we have no water pressure, absolutely no water in the building water supply piping, and no water in the water pump, we've lost prime and the two line jet pump may be unable to bring water back from the well.
Of course other problems can cause loss of water pressure, but if the problem is lost prime in the well pump, below is the procedure for restoring water pressure in the building. We discuss various causes of loss of water pressure at WATER PRESSURE LOSS DIAGNOSIS & REPAIR.
But where a two line jet pump is installed, you may have lost prime at the pump. The pump motor will run but no water is delivered. If this happens it is possible to re-prime the pump with water from another source. Check valves installed at the proper location at the pump and perhaps elsewhere can help prevent loss of prime on this system. (Other problems that can give the same symptom include internal damage to the water pump, a well that has run dry, or a piping leak between the well and the building it serves.)
If your 2-line jet pump (or other above-ground well water pump) loses prime and cannot draw water from the well, don't let it keep running as you may burn up the pump motor or damage the pump internal parts. Take these steps:
If your water pump is in the building and the pump keeps losing its prime, a shallow well jet pump well line could have a bad foot valve (in the well) and so be losing prime.
A leak in the well line can also lead to loss of prime. If priming the well water pump using one of our methods shown below seems to fix the problem but soon the well pump loses prime again, your plumber will want to check for a bad foot valve in the well or a leak in the well piping between the well and the building.
If you keep losing prime at the water pump where a two-line jet pump is installed, it's probable that a check valve at the pump or more likely at the foot valve in the bottom of the well needs to be replaced.
For example, a leak in the well piping inside the well can permit water in the piping and well pump to siphon backwards out of the well pump (and even the water pressure tank) down into the well when the pump as stopped.
Don't aggravate your plumber: remember to listen to your plumber. If you are too "directive" in telling the plumber what to do, s/he may do exactly what you ask even though s/he has a better idea of where the problem lies.
Carson Dunlop's sketch at left shows how a foot valve works and where it is installed. Replacing a foot valve in the well requires that the well be opened and the well piping be pulled out to permit removal of the old valve and installation of a new one.
After replacing the foot valve or well piping you should shock the well and well piping since you've probably contaminated it by laying your well piping and parts on the ground (and foot valves at the plumbing supplier are not kept in s
Readers of this document should also see Water Tank Types and before assuming that a water problem is due to the well itself, see WATER PUMP REPAIR GUIDE an specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost. terile containers).
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Frequently Asked Questions (FAQs) about the causes, diagnosis & cure for repeated loss of prime at a water well pump
Question: can I use an above-ground check valve instead of a foot valve
This was very helpful and describes exactly what my problem is. One question tho. Could I forgo the foot valve and put in a check valve to save money? - Frank Hobbs 6/22/11
Frank experts recommend replacing the foot valve but indeed I've occasionally seen people limp along for years without pulling the well piping to replace the foot valve by instead installing a check valve at the pump. I THINK that the chances of this repair working are better if your well is not deep.
In other words, your idea might work, but there is a reason that people use foot valves at the bottom end of well piping - the valve in that location is more reliable at preserving well prime.
And watch out - don't install multiple check valves.
Question: I can't get jet pump pressure up past 40 psi.
i have replaced a footvalve and a blown-out nipple at my pitless adapter. ( the well was not pitless - I dug a serious pit to do this! I have replaced the jet pump and pressure tank during the process. I checked for leaking toilets and piping leaks. The well suction line holds pressure now which was the origonal problem but now I can't get the jet pump to pressure up past 40 psi?
The pressure control switch cut outs on this system are 30 [pump on] and 50 psi [pump off] Any ideas would sure help! - Greg 4/10/12
Reply: check for a damaged pump
When a pump keeps running and we don't think that the problem is loss of water in the well itself, I suspect that during the prior well problem the pump itself was damaged - a bushing, bearing, or impeller; on occasion low voltage or bad pump motor will leave a pump running but weak.
However, a second possibility is a leak in well piping large enough that the pump just can't reach cut-off pressure. However if yours is a one-line jet pump, if there were a leak in the well piping or a bad foot valve, the system would not hold pressure when the pump was off. Therefore my first guess is the more likely explanation.
Question: how do I restore well prime after cutting both lines of a 2-line jet pump?
I have cut the two lines to a well pump and need to know how to get prime back. - Danny 7/18/12
Sure Danny, please just scroll down to the article links at the end of these comments and you'll see where to start - with the article titled WATER PUMP PRIMING PROCEDURE
Question: shallow well, F&W 2hp pump, pressure does not rise when pump turns on
I have a shallow well with F&W 2hp pump. The pump switch is set at 25-45. The pump shuts off at 45 but when it drops to 25, it turns on but does not rise. I have installed a new air tank (broken bladder), pump switch, and pressure gauge. My plumber replaced all piping on the pull side of the pump including a new check valve and eliminated an elbow. All ports on the pump are taped. House side seems secure.
Each time it cycles down I found I can get the pressure to rise by cutting the power to the pump by going through 4-5 cycles of an on/off sequence of 5 sec on- 5 sec off (assisting prime ???) Is there something else I might try before I turn to the well-foot valve etc ? Thank you - Dick 9/6/2012
Question: shallow well, loses prime when well sits unused over night
The comment [above] from Sept 6, 2012 sounds extremely similar to our situation. Shallow well that is legally grandfathered to exist, but no professional plumber can legally service it. Pump switch is set at 30-50 and correctly shuts off at 50. Anecdotally, it seems that if water is used soon after (within the next hour or two), the pump will correctly cycle back to 50.
Reply: check for a leaky foot valve or a leak in the well piping
Dan, the suggestions right on this page are a good place to start, beginning with check for a bad foot valve
Most often when a well and pump are capable of delivering good water pressure and flow, but prime is lost when the well sits unused, there is either a bad foot valve (or some one line jet pumps use a check valve right on the pump), or there is a leak in the well piping.
Question: shallow well loses prime unless we keep the pump operating frequently by leaving a trickle of water running
I have an almost identical problem as Dan...shallow well nobody will work on and will pump fine for days if I let a trickle of water flow in the tub so the pump has to come on every half hour or so. If I don't have water flowing for a couple of hours the pressure stays constant (even for days) but just cycling the pump doesn't get it to work. I have to open up the pump prime fill nut a slight bit to let the air excape then tighten it and turn on the pump, then repeat this 5-8 times until enough air has been purged out to get water to flow. There is a check valve in the pipe on the suction side of the pump and I've tried to test for air getting in at one of the hose clamps. I don't understand how air can be getting into the system at the foot valve...isn't it like a straw where you hold your finger over the top and the water can't flow out of the bottom, so air must be getting in somewhere where the line is above the water level?
Reply: tricks for finding and fixing a "hidden" leak in plastic well piping: check the connections
From your description it sounds as if you have a one line jet pump.
On a one line jet pump the air-leak in to the system can be at any connector above water, as when the pump is running it is "sucking" on the well pipe between the pump and well bottom.
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