Priming plug on a jet pump (C) Daniel Friedman How to Prime a Well Pump Through the Pump Body

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How to prime the water pump:

This article describes how to prime a water pump to restore water pressure to a building by pouring water through a plugged opening in the well pump. The procedure is pretty easy: we'll will describe

How to find the well pump priming plug

How to remove the plug, andi f the water pump priming plug is not easy to remove we suggest an alternative procedure that skips that step.

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Detailed Step by Step Procedure for Direct Priming a Well Water Pump

Jet pump priming plug (C) Daniel FriedmanOur photo at page top shows the plug that would be removed to prime this Meyers pump by pouring water into the pump housing.

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.

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.)

Turn off the water pump if it is running "dry": If your 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. The pump won't be damaged if it runs dry for a minute or a few minutes, but leaving it running for half an hour with no water could be another story.

Before following this procedure to directly prime a dry water pump that has lost its prime, you might want to try the alternative water pump prime method that avoids any disassembly or the need for tools - described
at PRIME the PUMP using a GARDEN HOSE.

Our photo (left) shows the two line F&W (Flint and Walling) two line jet pump in our lab. That big brass plug in the center of the top of the pump body (center of the photo) closes the opening that is used to prime the pump if it should be dry. Don't take out this plug before reading the instructions below.

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.

Reader Question: can't get the new pump to deliver water - New Goulds JS 10 well pump on a shallow well

31 August 2015 Phil said:

I tried to install this pump on my shallow well. The motor works and the impeller spins but the pump does not provide any suction at all at the top of the well pipe. All connections are tight, the check valve works and when I put a pitcher pump on the well, I got water flowing after 4 strokes.

Can I just replace the impeller and attach it to the shaft on the motor? I even took the cover off the impeller housing and made sure the slots on the impeller wheel were open.
Thanks Phil



The JS-10 to which you refer is probably a convertible Goulds shallow well pump model JS-10.

If the pump is running dry, without prime, I'd try priming the system first. In addition to our own text on that procedure using several methods, I include some advice from the pump manufacturer just below.

According to Goulds, this JS-10 well pump has this feature: "Diaphragm retains water in the casing to ensure the mechanical seal can never run dry."

Watch out: That does not mean that you can install this pump and run it without an initial priming operation. Most pumps will be damaged if run without water. Once the pump has been primed successfuly and has pumped water, the company says the pump is indeed self-priming. But for an initial installation, surely you need to prime the pump.

The pump is delivered set-up for a shallow-well application. If you are running it on a deep well (more than 25 ft) you'll need a special conversion kit provided by the manufacturer. I'm guessing, since you said "shallow well" that you know that.

Quoting Goulds - Xylem:

Deep well jet pumps require a pressure control device on the discharge to provide back pressure to the jet assembly. Failure to control the amount of discharge by adjusting the back pressure (pressure control valve setting) will cause the pump to lose prime. On pumps with Iow control valve settings, up to 40 psi, a simple ball valve or AV15 will work. On systems with control valve settings of 40 - 80 psi an AV22, AV22KIT or AV21 is required. They measure the pressure on the outbound side so that the high pressure does not open the 30-50 psi switch and turn the pump off.

Gould's general manual for pumps of this type warrns about other snafus including these notes on priming the pump:

It is very important to eliminate high spots and dips in suction piping as they will trap air and make the system very hard to prime. Never route the piping up above and then down to the pump suction. Suction piping should be either straight from the well to the pump or should slope upward to the pump. Pumps do not ?hold? prime, piping systems and check valves do.

On sand points or driven wells you can install an in-line check valve near the well head or at the pump and use the well casing as the suction pipe. The closer the check valve is to the well the easier the system will prime.

Priming a Shallow Well System

Priming means filling the pump and suction pipe with water. Most shallow well jet pumps handle air well and will evacuate air from the suction line but it may take several minutes to prime depending on depth to water, and pipe size and length.


It is easier to prime a pump if you allow all the air to escape from the pump and the pipes, the water cannot go in unless the air can escape!

Remove the pipe plug or pressure gauge bushing in the discharge tee to fill the pump with water. On shallow well pumps you should remove the 1 ⁄8" pipe plug located between the suction and discharge ports to allow air to escape as you fill the casing with water.

The port will be located on either the top of the casing or the top of the shallow well adapter. Fill the pump and as much of the suction pipe as possible with water through the discharge port.

Replace the 1 ⁄8" pipe plug and discharge gauge/bushing. Open the faucet closest to the pump/tank a small amount to allow air to escape the system. Do not open it too much or the pump will expel too much water and you will have to reprime the pump casing.

On jobs with long suction pipes you may have to add water to the pump casing several times to complete the priming process. Go to Power Motor. 

Priming a Deep Well System

Priming a deep well system means filling the pump and the suction/pressure pipes with water. Deep well single stage and multi-stage pumps require a complete prime before starting. Filling the pipes with water before installing the pump will make priming faster and easier.


To insure a complete prime we recommend removing the angled 1 ⁄8" vent plug located just above the suction pipe on horizontal pumps.

This will allow the air to easily escape as water enters. Our horizontal convertible deep well jets should be primed through a tee or the AV22 at the pump discharge. The tee is not supplied by Goulds Water Technology.

Our vertical deep well jet pumps have built-in pressure control valves. Priming is done through the pressure gauge port on the pressure control valve. Most verticals have a vent plug located on the side of the motor adapter that vents the seal cavity which is the high point inside the pump. Removing this vent plug will make priming much easier. 

If your pump is going to lift more than 25 ft it needs to be converted to a deep well set-up including installation of a conversion kit.


Continue reading at PRIME the PUMP using a GARDEN HOSE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WATER PUMP PRIMING DIAGNOSTIC FAQs and WATER PUMP PRIMING DIAGNOSTIC FAQs-2 questions & answers posted originally on this page.


Or see WATER PRESSURE LOSS DIAGNOSIS & REPAIR if priming the pump is just not working for you

Suggested citation for this web page

PRIME the PUMP, HOW TO at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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