Photograph of a sketch of a 2-line jet pump Two Line Jet Pumps for Drinking Water Wells: Installation & Repair
What is a two-line jet pump? What do the two pipes do? How does a jet pump work?

  • TWO LINE JET PUMP - CONTENTS: Explanation of deep-well Two Line Jet Pumps & Drinking Water Wells, how to troubleshoot pump & well problems & how to fix them - What are the components of a two line jet pump water supply system? What types of wells use a two-line jet pump for water delivery. From what depth can a two line jet pump deliver water? Types of wells and water supply systems and what to watch out for with each. Well pump & water tank diagnosis & repair procedures. Electric pump motor troubleshooting guide - table of problems & solutions
  • POST a QUESTION or READ FAQs about 2-line jet pumps on water wells
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Guide to 2-line jet pumps on water wells:

This article describes the components of a two-line jet pump water system, what the components look like, and what they do.

We discuss how two-line jet pumps are selected, installed, jet pump troubleshooting, & repair procedures.

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What are the Components of a Well with a Two Line Jet Pump?

Copper tubing on pressure control switch (C) Daniel Friedman Two line jet pump diagram (C) Carson Dunlop'

Refer to the illustration at above right, courtesy of Carson Dunlop and also to our rough sketch provided below to see the components providing well water to a building served by a two-line jet pump located apart from the well.

In our drawing the two line jet pump which draws water from the well and the water pressure tank are shown located separately from the well itself, and the well and its casing are shown located inside of a well pit.

The actual lift capacity will vary depending on the pump horsepower and other factors such as piping length, bends, diameter. Common lift height is about 30 to 80 feet but some deeper installations work.

For example, a twin pipe jet pump plumbing arrangement requires [typical specifications]


Well pits such as the one we've drawn are used especially in climates exposed to freezing weather, as a way to get access to the well casing and well piping and to route well piping out of the well through the top of the well casing and on to the building while protecting it from freezing.

In addition to showing a well pit in this sketch, we discuss and illustrate well pits a bit more

A more modern device, the pitless adapter which permits a water tight piping connection out through the side of the well casing is shown in our sketch at Components of a Drilled Well with a Submersible Water Pump.

What is the Pumping Capacity in Gallons per Minute for a 2-Line Deep Well Jet Pump?

A two-line jet pump can typically raise water from depths of 30-feet to 80-feet, and at water delivery rates of 4 gpm (gallons per minute) (for a 1/2 hp 2-line jet pump serving an 80 foot deep well) to 16 gpm (for a 1 hp 2-line jet pump serving a 30 foot deep well).

At WATER PUMP CAPACITIES TYPES RATES GPM we compare the pumping capacities of one line jet pumps, two line jet pumps, submersible well pumps, and other water pumping methods.

A nice example table of Deep Well 2-Line Jet Pump Capacities for 1/2 hp and 1 hp deep well pumps is provided in the Water Ace Jet Pump Installation Manual and excerpted below to illustrate the factors that determine well pump capacity. Both of the charts below are for 2-line jet pumps produced by Water Ace. 2-Line jet pumps intended for deep well use and made by other manufacturers can be expected to have similar capacities.

Deep well pumping capacity - Water Ace Co. Deep well pumping capacity - Water Ace Co.

The Water Ace charts (shown in part above) make clear that the capacity of a deep well pump to deliver water at a given flow rate varies by these factors:

  1. the depth of the well (the bottom scale in the two charts)
  2. the pump horsepower (the color codes indicate pump model and horsepower HP variation)
  3. The well pump model (the right hand table is for the company's more powerful well pump series of 2-line jet pumps)
  4. The condition of well piping, including pipe diameter, length, number of bends or elbows
  5. The presumption that the entire piping system has no leaks

Permission requested, Water Ace Corp. Aug 2010 - Pentair Pump Group.

Watch out: Safety warnings are throughout any pump manufacturer's instructions. Because some pump models are capable of developing internal pressures of more than 100 psi, if your building piping, pressure relief valves, safety controls, wiring, and plumbing are not properly installed, very dangerous conditions including electrical shock, tank explosion, and leaks or floods can occur.

How a Two-Line Jet Pump Works to Get Water Out of the Well

Photograph of a two line jet pump

A two line jet pump refers to the observation that two pipes are connected between the jet pump and the well. In our photo at left you can see the two black plastic lines leaving the front of the water pump.

A two line jet pump draws water out of the well by magic: it forces water away from the pump and into the bottom of the well through one of the pipes (usually the smaller diameter pipe).

At the bottom of the well water from the jet pump is forced through a venturi device (a sort of funnel shaped opening) and then back upwards into the larger diameter pipe. Water flowing through the venturi device at the bottom of the well piping draws still additional water out of the well and into the larger diameter pipe that flows back to the building.

The requirement to have some water to send down to the well in order to bring a larger quantity of water back is why a two line jet pump can't provide any water or water pressure in a building if it loses its prime.

See WELL PUMP PRIMING PROCEDURE if you need to re-prime your jet pump.

In our sketch above see the two arrows showing water entering the bottom of the piping.

The following list and definition of two-line deep well jet pump and water well parts and terms is organized from the top of the drawing towards its bottom and uses names that correspond to those shown in our ugly sketch above.

Photograph of a two line jet pump

What is the Well Piping Foot Valve used in a well and what goes wrong with foot valves?

Foot valve sketch (C) Carson Dunlop Associates

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.

See WELL PIPING FOOT VALVES for details about this component.

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 you should shock the well 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 sterile containers).

We discuss how to shock a well

2-Line Jet Pump Well Pump Diagnostic Table

Some of the well pump troubleshooting suggestions in this list can be found at the Betta-Flo Jet Pump Installation Manualfrom the National Pump Co.

Things to Check if the Well Pump Will Not Start
Pump Trouble Cause Diagnostic Procedure Repair Procedure
Blown fuse, tripped breaker Replace fuse or breaker - does the pump run and keep running normally? Be sure proper breaker or fuse size in ampacity is installed
Low voltage to the pump Check with VOM at the pressure control switch or at the pump wiring Be sure the proper size of wire is used for the ampacity and length of circuit; Test for low voltage to the building.
Loose or broken pump wire Check wiring against the pump installation manual diagram, check all connections for tightness, shorts, burns, damage Rewire or repair or replace wiring
Burned out pump motor Check that the pump pressure control switch is trying to turn on the pump and that there is voltage at the pump wiring Repair or replace the pump motor
Bad pump pressure control switch Check the switch contacts for burning or wear Adjust or replace the pressure control switch. Temporary emergency repair by cleaning the switch contacts may be possible.
Bad pump pressure control switch Check the tubing connecting the pressure switch to the pump housing for clogging Clean or replace the tubing and be sure the connections are not leaky - an air leak will prevent the switch from sensing pressure properly
Bad pump impeller or impeller seal leak Turn off electric power to pump, see if you can move the impeller or motor - if it won't turn it is jammed or damaged Remove obstruction in impeller housing, inspect for and replace damaged impeller or frozen motor.
Bad pump motor starting capacitor Use a VOM in ohms setting to check resistance across the capacitor. If the meter does not move (no current flows) the capacitor is "open". If there is zero resistance the capacitor is shorted. Replace the starting capacitor
Pump motor shorted out, jammed, burned up Fuse blows or breaker trips as soon as the pump tries to turn on. If the external wiring is ok (no short circuits) the motor is shorted internally Replace the pump motor
Things to Check if the Pump Motor Starts but Overheats and Trips its Reset Button
See ELECTRIC MOTOR OVERLOAD RESET SWITCH for how to find and reset this button
Bad line voltage Use a VOM to check the voltage level at the pressure control switch If voltage is too low, check voltage at the electrical panel and check that the proper size wiring was used for the ampacity and length of run and that there are no partial shorts or damaged wires or connectors
Incorrect motor wiring Check the actual electrical wiring against the motor wiring diagram or the installation manual for the equipment Reconnect wiring properly
Motor is too hot due to surroundings - inadequate ventilation Check the air temperature where the motor is located. If the air temperature is over 100 degF, the pump may be too hot and its thermal overload switch tripping because of the environment, not a pump problem. Install adequate ventilation, or if needed, shading, or relocate the motor/equipment to a cool location
Pump operates too long at low water pressure If the well recovery rate is too poor and the pump is operating at low water pressure, possibly because a tailpiece is installed to prevent air injection and pump burnup, the pump may be overheating. Install a valve on the water discharge line and reduce water flow to increase water pressure inside the pump itself.
What to do if the well pump runs continuously or runs too often
If the Well Pump Motor Runs Too Often If the pump runs too often the cause may be a control problem, water tank problem, piping problem, or a well problem.

See INTERMITTENT CYCLING WATER PUMPS if the pump runs at odd times for no apparent reason.

See WATER PUMP SHORT CYCLING CAUSES if the pump is turning on and off too frequently.

If the Well Pump Motor Keeps Running & Won't Stop If the pump won't turn off the cause may be a damaged pump control, a plumbing or fixture leak, or a well problem.

Watch out: If the pump motor won't shut off you should turn off electrical power to the pump to avoid damaging it, then diagnose the problem.


This article series describes various types of drinking water sources like wells, cisterns, dug wells, drilled wells, artesian wells and well and water pump equipment. We provide advice about what to do when things go wrong.

Jet Pump Conversions & Piping Connections

Red Lion RJC-100 convertible jet pump (C) Alexz

Reader Question: how do I connect mis-aligned 2-line jet pump openings to the well piping?

27 April 2015 Alex said:

I am planning on replacing my very old well pump, but I realized that my new pump has the larger diameter pipe coming into the top, whereas the old pump had the larger diameter pipe on the bottom. Is it always the case that the larger diameter pipe is the suction line?

Any tips on how I should plumb it? I don't have the space to plumb in on the opposite side of the well from where the current pump sits. Is it acceptable to use flex line, or should I stick with rigid (copper or brass)?

[Click to enarge any image]

Reply: piping connections for a Red Lion RJC-100 convertible 2-line jet pump

Yes the larger diameter pipe opening on a 2-line jet pump is the suction line. You can tell me the brand and model of pump and we ought to be able to find the pump specifications and installation manual that will make that clear if you're missing those documents.

27 April 2015 Alex said:

Thanks DanJoeFriedman. My new pump is a Red Lion RJC-100. I have the manual. I was just confused by the fact that the old pump had the suction and the pressure holes opposite of how my new pump is configured. In order to install this new pump, I think I'm going to have to rotate the cap 180 degrees. The way it's oriented now, the larger diameter pipe (suction) is directly in front of the pressure pipe, so I'm not able to plumb it without getting really creative. Hard to explain, but I'll try to post another photo. Hopefully one of these works.



I took a look at your photo and will add it in this article above as well so that other readers may offer a suggestion (let me know if you do not want that action).

The face openings on the new Red Lion RJC-100 cannot be rotated, and indeed the inlet and outlet openings are reversed in position from your old pump.

If you want to use the new unit I suggest giving yourself adequate working space to make the necessary connections by moving the location of the new pump to one side - more or less as you have it positioned now, or elevating it a foot if needed as well. By removing the union and street-elbow at the well top and starting there you can make the necessary routing changes, routing the jet pump inlet and outlet lines to their destinations. It'll take a two more elbows but is do-able.

Before doing that, however I'd give the company's tech support a call or email to ask if in fact the face of the pump can in fact be rotated 180 OR if the pump can be installed upside down, as I agree that'd make piping simpler.

Red Lion convertible jet pump shown in 2-line set-up - Mastercraft one-line jet pump -

Watch out: convertible jet pumps like the Red Lion RJC-100 (shown at above left) that can be swapped between a shallow well (typically from 25 ft) one-line jet pump to a deep-well two-line jet pump are typically capable of lifting (in the 2-line jet pump conversion) from a depth of about 90 feet.

A few one line jet pump models (such as the Matercraft one line jet pump shown at above right) advertise that they can lift from 70 feet, but if you take a closer look at the pump specifications you may find that although the pump can lift water from that depth its flow rate capacity in gallons per minute (GPM) may be significantly reduced.

For deeper wells using a 2-line jet pump you may require a different pump model.

Contact the Red Lion pump company in the U.S. or Canada at:
301 N MacArthur Blvd.
Oklahoma City, OK 73127-6616

Sales and Marketing:
Suite 101 - 310 De Baets St.
Winnipeg, MB R2J 0H4

Customer Relations:
61 Parr Blvd, Unit 1
Bolton, ON L7E 4E3

Tel: t 888.956.0000

Red Lion, itself a company dating from 1935, has recently picked up the Little Giant pump brand that we've used for decades.

You can use ABS piping and plastic elbows that may tolerate vibration with less leak risk; note that the manufacturer emphasizes that the pump should be securely mounted to a solid base.


Continue reading at PUMP, TWO LINE JET OPERATION or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.




Or see WELL CAPS & COVERS - requirements for sealed well caps & covers, requirements for vents & exclusion of vent requirements for some jet pump installations.

Suggested citation for this web page

WATER PUMP, TWO LINE JET at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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