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Explanation of Two Line Jet Pumps & Drinking 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.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
What are the Components of a Well with a Two Line Jet Pump?
 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.
Readers of this document should also see our other diagnostic guides for water pumps, wells, motors, in table form:
Readers of this document should also see PUMP, TWO LINE JET OPERATION, and see our Well Pump Troubleshooting Diagnostic Guide for a table of diagnostic steps for jet pumps.
See Water Tank Types and before assuming that a water problem is due to the
well itself, see Water pump and pressure tank repair diagnosis & cost which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost. If your building has water pressure problems, see WELL WATER PRESSURE DIAGNOSIS. Readers whose wells simply run out of water should also see How to Test Well Water Quantity and see How to Get More Water From a Well.
Refer to the illustration at left, 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.
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
at Well Pits
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.
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:
- the depth of the well (the bottom scale in the two charts)
- the pump horsepower (the color codes indicate pump model and horsepower HP variation)
- The well pump model (the right hand table is for the company's more powerful well pump series of 2-line jet pumps)
- The condition of well piping, including pipe diameter, length, number of bends or elbows
- 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
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.
- A pair of well pipes leave the well casing through a water-tight cap on top of the casing and
are connected to the appropriate fittings on the two line jet pump which is (probably) located in the building it
serves.
The well casing top in this example is located inside of a well pit but it
could be simply buried in the soil. It is particularly important that the well cap on the casing be water tight
since otherwise unsanitary surface water and
debris can enter the well casing. Many well caps are not water tight, which is why modern drilled well casings extend above ground level.
- Compression Seal Well Cap is a special well cap with openings to permit passage of the two water lines (and maybe an air vent tube)
out of the well to above ground.
A compression seal well cap consists of steel top and bottom plates which "sandwich" rubber fittings which surround
the water piping. As the two plates are bolted together they squeeze the rubber "sandwich" gaskets causing them to expand and seal both around
the water piping and inside the diameter of the well casing.
- A "two-line" jet pump is shown outside of the well, either inside of the building or perhaps in a well pit or well house. "Two line" refers
to the fact that two water pipes connect the pump to the well. Since the lift capacity of a two-line jet pump is not
limited to the shallow-well depth of 27' chances are that where you find a two line jet pump installed
it is drawing from a deep water well. Our sketch shows the pump connected to a water pressure tank which in turn supplies water to the
building. The pressure tank is usually located very close to the jet pump but it could be elsewhere.
- Well Jet and Well Piping Foot Valve is a venturi device through which the two line jet pump sends water to collect and
bring still more water back into the building. See WELL PIPING FOOT VALVES for details. You can see Carson Dunlop's sketch of a foot valve here and also at the end of this list.
- Well Jet & Foot Valve Clearance from Well Bottom: (not shown) means that the well piping, bottom venturi, and foot valve are inserted
into the well some distance from the very bottom of
the well (inches to a few feet). We need this clearance to reduce the tendency of the well pump to pick up mud and debris from the bottom of the well.
- Static head (not shown in this sketch) is the height of the column of water inside of the well between the bottom of the foot valve and the
top of the water when the well is at rest. We discuss "static head" and well recovery rates in detail at How Much Water is In the Well?
What is the Well Piping Foot Valve used in a well and what goes wrong with foot valves?
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 at WELL SHOCK / CHLORINATION PROCEDURE our WELL SHOCKING GUIDE
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Well Pump Troubleshooting Diagnostic Guide
Some of the well pump troubleshooting suggestions in this list can be found at the Betta-Flo Jet Pump Installation Manual from 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 |
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| 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. |
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| 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 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.
See WATER PUMP WONT STOP RUNNING
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
- Deep Well Jet Pumps, Government of Alberta, Agriculture and Rural Development, toll free in Alberta at 310-FARM web search 07/24/2010, original source: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex639
- Betta-Flo Jet Pump Installation Manual, National Pump Co., LLC., includes helpful well pump troubleshooting tips as well as basic jet pump installation details. Web search 07/24/2010, original source: http://www.nationalpumpcompany.com/Documents/OIM/Betta%20Flo%20IOM%20Jet%20Pump.pdf
- Water Fact Sheet #3, Using Low-Yielding Wells [ copy on file as /water/Low_Yield_Wells_Penn_State.pdf ] - , Penn State College of Agricultural Sciences, Cooperative Extension, School of Forest Resources, web search 07/24/2010, original source: http://pubs.cas.psu.edu/FreePubs/pdfs/XH0002.pdf
- Smart Tank, Installation Instructions [ copy on file as /water/Smart_Tank_Flexcon.pdf ] - , Flexcon Industries, 300 Pond St., Randolph MA 02368, www.flexconind.com, Tel: 800-527-0030 - web search 07/24/2010, original source: http://www.flexconind.com/pdf/st_install.pdf
- Typical Shallow Well One Line Jet Pump Installation [ copy on file as /water/Jet_Pump_Grove_Elect_Jet_Pumps_1.pdf ] - , Grove Electric, G&G Electric & Plumbing, 1900 NE 78th St., Suite 101, Vancouver WA 98665 www.grovelectric.com - web search -7/15/2010 original source: http://www.groverelectric.com/howto/38_Typical%20Jet%20Pump%20Installation.pdf
- Typical Deep Well Two Line Jet Pump Installation [ copy on file as /water/Jet_Pump_Grove_Elect.pdf ] - , Grove Electric, G&G Electric & Plumbing, 1900 NE 78th St., Suite 101, Vancouver WA 98665 www.grovelectric.com - web search -7/15/2010 original source: http://www.groverelectric.com/howto/38_Typical%20Jet%20Pump%20Installation.pdf
- Water Ace Jet Pump Installation Manual, instructions from Water Ace Pump Co., web search 08/28/2010, original source: http://www.waterace.com/pdf/R510%20R520%20and%20R100%20Jet%20Pumps%20Manual.pdf
Consumer hotline: 800-942-3343 - instructions for the installation and maintenance of
Water Ace shallow well pump Model R510 1/2 HP
Water Ace deep well pump Model R100 convertible 1HP and
Water Ace deep well jet pump Model R250 convertible 1/2 hp.
Quoting from the company's website:
The Water Ace Pump Company is a dynamic, rapidly growing retail pump manufacturer, backed by a tradition of over 125 years of excellence. We offer a complete line of sump, sewage, lawn sprinkler, swimming pool, submersible well and jet pumps as well as pressure tanks and accessories.
- Water Ace Jet Pump Installation Manual, from Water Ace Pump Co., web search 08/28/2010, original source: http://www.waterace.com/pdf/RTS5%20RTS7%20RTS10%20RC5%20and%20RC10%20Jet%20Pumps%20Manual.pdf
Consumer hotline: 800-942-3343 - instructions for the installation and maintenance of Water Ace pump models:
Water Ace Shallow Well 1-line Jet Pump Models RTS5 (1/2HP), Model RTS7 (3/4 HP) and RTS10 (1HP)
Water Ace Deep Well 2-line Jet Pump Models RC5 (1/2 HP) and RC10 (1HP)
- Water Ace Submersible Well Pump Installation Manual, from Water Ace Pump Co., web search 08/28/2010, original source: http://www.waterace.com/pdf/23833A019%20Well%20Pumps%20Eng.pdf
Spanish and French language submersible well pump installation manuals are available from the company.
Consumer hotline: 800-942-3343 - instructions for the installation and maintenance of Water Ace pump models:
- Access Water Energy, PO Box 2061, Moorabbin, VIC 3189, Australia, Tel: 1300 797 758, email: sales@accesswater.com.au Moorabbin Office: Kingston Trade Centre, 100 Cochranes Rd, Moorabbin, VIC 3189
Australian supplier of: Greywater systems, Solar power to grid packages, Edwards solar systems, Vulcan compact solar systems, water & solar system pumps & controls, and a wide rage of above ground & under ground water storage tanks: concrete, steel, plastic, modular, and bladder storage tanks.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
 The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
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