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This article describes the sequence of operating steps in a submersible well pump water system.
The process of diagnosis and the costs of the repair are explained. Consumer advice on saving money on water supply repair costs includes a review of the parts and labor costs of a typical well pump and pressure tank replacement case.
Carson Dunlop's sketch at page top shows the components of a submersible well pump water supply system.
How a Submersible Well Pump Water System Works - Sequence of Operating Steps
What happens when you turn on the water at a faucet in a building whose water is supplied by a submersible well pump?
The following steps describe normal operating of a building well pump and water supply system. Other cases in which the well pump controls are not working properly, there is a problem with the controls, pressure tank, pump, or well itself are discussed
at WATER PRESSURE REPAIR GUIDE & COSTS
at WELL WATER PRESSURE DIAGNOSIS. Our sketch (left) shows a cutaway view of a submersible well pump.
[Click to enlarge any image]
Turn on building water at a plumbing fixture: open a sink valve, tub valve, or flush a toilet.
Water runs out of the supply faucet, into the fixture, down the drain
Water pressure and flow are being supplied to the building from a water pressure tank. If we didn't use a pressure tank, because water is not very compressible, the second water was turned on, water pressure in the system would drop below the pump cut-on pressure, the pump would turn on, and probably bring water pressure up to the cut-off pressure quickly, causing short cycling and burning up pump controls or a pump motor.
Note: The illustration at above left is adapted from an original drawing by Trisha A.D. Nelson, A.C.E., Inc., is a consulting engineering firm in Atlanta, GA. Website: www.aceforensics.com
Pressure in the water pressure tank and in the building piping system drops down to the well pump cut-in pressure. Typically this is 20 or 30 psi on a residential water system. On a submersible well pump system the cut-in pressure may be as much as 40 psi.
The well pump pressure control switch senses the pressure drop, closes an internal electrical relay switch to turn on the submersible well pump. See WATER PUMP PRESSURE CONTROL SWITCH.
A separate pump relay switch turns on the submersible well pump as follows: the well pump pressure control switch senses the pressure drop, closes its internal electrical relay switch to in turn send power to a heavier-duty pump relay switch (usually mounted on a wall near the pressure tank and other water controls). The pump relay switch actually turns on the well pump.
In the submersible well pump photo above you can see extra pump relay switch boxes at the left of the red arrow. The arrow itself points to a submersible well pump that has been removed from the well and left in the utility space that houses a water pressure tank and control that are partly visible in the right side of the photo.
Running a high-amp well pump off of a little pressure control switch will often burn up the switch contacts, or the amperage draw may exceed the rating of the pressure switch itself - that's why the relay switch is used.
See WATER PUMP RELAY SWITCH.
The well pump motor runs, drawing water back into the building from the well by "sucking" water up from a shallow depth (a one-line jet pump can't draw water from much below 25 feet)
Water is forced into the building water pressure tank and simultaneously into the building piping and on to the plumbing fixtures.
If the pump sends water into the building faster than water is flowing out of the open faucet or plumbing fixture, the pump will "get ahead" of the water flow, successfully pressurizing the water tank, causing the pressure switch to turn off the pump (see step 10 below).
If the pump cannot send water into the building faster than water is flowing out of the open faucet or plumbing fixture, the well pump will run continuously and water will flow out of the open faucet or plumbing fixture at a rate limited basically by the pump's water delivery flow rate in gallons per minute. You'll also find this condition if a building water supply pipe bursts.
We say "basically" because the well piping and building piping and faucets themselves offer some back-pressure against the pump's flow rate. In this case, the well pump will continue to run until the building faucets or plumbing fixtures are turned off. At that point ...
The well pump pressure control switch senses that water pressure has increased to the cut-out point, opening its switch and turning off electrical power to the well pump. The well pump has re-pressurized the building water tank and piping up to the cut-out or cut-off water pressure.
Cut-out pressures are typically set to 40 psi or 50 psi. If you set the cut-out pressure too high the pump may never reach it and will run continuously, or you may find frequent plumbing leaks, or even an unsafe condition, risking bursting a pipe or water pressure tank. Many submersible well pumps are capable of pumping to high enough pressure to damage the plumbing system or burst a water tank. That's why water pressure tanks need a pressure relief valve installed.
The foot valve closes (at the bottom of the well piping) and/or a check valve located in the building on or close to the well pump closes, preventing water and pressure from flowing backwards down into the well, losing building water pressure and possibly losing pump prime
. However because the submersible pump is inside the well at the bottom of the well piping, loss of prime is not a problem directly - that is, the submersible pump, because it is under water, will have no trouble re-starting. But still a bad check valve or foot valve means you may lose building pressure between well pump cycles.
See WELL PIPING FOOT VALVES
see WELL PIPING CHECK VALVES.
Where is the Well Pump?
Take a look at our well casing photograph at above left. See that small gray conduit rising at the left side of the well casing? The conduit carries electrical wires into the well. That's one way to recognize that a submersible pump is installed.
When a water pump is inside the well, it can be tricky to know when the pump is actually on or off, though usually we hear the pump relay clicking, and some relays have a light that indicates that the relay is telling the pump to run.
The pressure switch calls for pumping by switching a relay in the pump relay, that actually turns the pump on and off. So a secondary potential problem would be in the relay itself, but we would look at the pump pressure control switch first.
How to Diagnose Poor Submersible Pump Water Pressure
Separately we also provide
a WATER PRESSURE PROBLEM DIAGNOSIS TABLE. The following articles pertain if you have a private well, pump, and tank system for your building or if your incoming community water supply pressure and flow are just too low to start with:
Water Tank Problems?
See WATER PRESSURE TANK REPAIRS. Examples of water tank problems include poor water pressure or the well pump rapidly turning on and off (short cycling).
Water pump problems? Examples of water pump problems include poor water pressure or no water pressure at all. See
Water piping or well piping problems? If your water pump keeps losing prime, a shallow well jet pump well line could have a bad foot valve
(in the well WELL PIPING FOOT VALVES) or there may be a bad check valve on well piping at or near the water tank or near the above-ground water pump
(CHECK VALVES, WATER SUPPLY) and so be losing prime. A leak in the well line piping itself can also lead to loss of prime.
Well Problems? Do you run out of water or after running water for some interval water pressure and flow are poor? Well problem diagnosis starts
at WELLS CISTERNS & SPRINGS.
Bad water pump or water tank pressure regulator control?
See WATER PRESSURE REDUCER / REGULATOR (not usually installed on private well and pump systems, often present on municipal water supply systems that use an in-building local water pump and pressure tank to boost pressure). Water pump pressure regulator switch diagnosis and repair steps include these:
How to Adjust Water Pump Pressure: The detailed, step by step procedure for inspecting and adjusting the water pressure control switch is
discussed in detail
at ADJUST PUMP PRESSURE CONTROL.
Diagnosing Water Pump Short Cycling on and off: If your water pump is clicking on and off too often or quite rapidly
see SHORT CYCLING.
Diagnosing Water Pressure Drops without explanation when the pump stops,
see WATER PRESSURE FALLS SLOWLY, ERRATIC PUMP: bad pressure control switch, building water running or leak, bad pressure gauge, bad check valve, bad foot valve.
Diagnosing & Repairing Lost Air in the Water Tank: The problem of lost air in the water pressure tank along with how to correct that condition are discussed
at SIGNS OF AIR LOSS.
Diagnosing & Repairing a Water Pressure Control or Water Pump Control Switch: We discuss diagnosing and repairing a water pressure control switch that sticks "on" or "off" or simply won't operate,
at water pump Pressure Switch Repairs.
Bad Hot Water Pressure?
See HOT WATER IMPROVEMENT especially if the building cold water pressure is acceptable but hot water pressure and flow are poor. Accumulated debris in a water heater, and debris from a corroded or disintegrating hot water tank dip tube or hot water tank sacrificial anode can also block the hot water outlet opening, resulting in low hot water pressure in a building.
Problems with water treatment equipment can cause loss of water pressure or no water flow: a clogged water filter, or a malfunction in water disinfection or other water treatment equipment can cause a reduction in water pressure or even a complete stop in water flow in a building.
See WATER FILTERS, HOME USE for details about clogged filters,
see WATER TREATMENT EQUIPMENT CHOICES for our complete list of types of water treatment equipment.
Continue reading at WATER PUMP, SUBMERSIBLE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
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in the summer we run out of water
(June 9, 2012) Jeannie D said:
My question is we have a 160 ft. well and for the past two years in the summer we can't take a shower and
run the air conditioner at the same time. The water presser in the shower comes and goes. We had the well
pump changed in 2010 becuase it quit. I would love to fix the problem we have company coming but my
husband refuses to have someone check it out and says there is drought. We have water, just can't run two
things at the same time. I say there is something else wrong.
Can you please help.!
When your well pump is a submersible unit, as it is inisde the well you'll never hear the pump itself. But you may hear one or even two well pump relay switches that click when the pump is started or stopped. If your well pump is a small horsepower unit the pressure control switch on or close to your water pressure tank turns the pump on and off in response to water pressure - and the relay may emit a click at the start and stop of the run cycle. If your pump is a higher horsepower unit your pressure control switch in turn operates a separate, heavy duty well pump relay switch usually mounted nearby, and that switch is what actually turns the pump on or off. (The smaller switch can't handle high amps switching without risking burning the contact points, so two relays are used).
If you hear the clicks very frequently, say every 20 seconds or less, your pump is turning on and off too frequently - search InspectApedia for "well pump short cycling" for diagnosis and cure advice if needed.
Since A/C and well pumps are completely independent systems, I have to guess that perhaps they are (and should not be) on the same circuit which is overloaded and is tripping a breaker?
Question: dug well runs dry in summer - can I have a water truck deliver water into my well?
(Sept 5, 2012) Corey M said:
I have a dug well that is just over 30ft deep. Due to an unusually dry summer I have had my well run dry several times (four teenage daughters!) the pump recently burnt out and I had to replace it and the pressure switch (30-50). I have been able to refill the well using 45gal drums with municipal water, but I would like to know if I can install one of the drums as an indoor emergency storage tank close to the pressure tank in the basement and some sort of "Y" gated valve to manually switch between the well and the indoor tank. That way I could still at least have water in the system to allow flushing toilets or running limited amounts of laundry or dishwashing while the well replenishes itself.
Reply: not a good idea
Corey, pouring water back into a dried out water well to "refill it" is probably not useful and provides no lasting relief, and will perhaps lose and thus waste some of the water poured therein.
To install an emergency water system you could indeed feed your local water pump from water drawn from the 45-g steel drum, though it's not going to last very long. I'd give some thought to a larger water storage tank installed in the building or outside above or on top of the building if the structure permits; when you have water in your well, even if it's at a very slow recovery rate, you can use it to slowly fill the larger storage tank that will act as a buffer to give functional water when you need it, recovering slowly when water is not being used.
Question: can't find the well, no water.
(Feb 13, 2014) Bill said:
Unable to locate our outside well and we have no water. No visible pipe above ground. Suggestions?
If the well piping is metal a plumber can trace its location using an electronic tool. Follow the ppe to the well.
Look a around the water tank and equipment for a sketch left by a prior owner or service tech.
Call prior owners and ask I'df they are alive
Call local well drillers to ask if one of them has a record of drilling your well- I have had very good luck with this approach
Look around on the site for reasonable well locations e,g, awayy from septic
Depending on well age you may spot a long shallow depression marking the original well pipe excavation.
Finally, last resort, excavate outside making a cross trench near the well pipe exit from the building. Note pipe direction, move out 10 or 15 feet and repeat - this may be less total digging than just digging up the whole pipe to follow its length to the well.
Questions & answers or comments about how submersible well pumps work and the sequence of operating steps - help in diagnosing well pump troubles.
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Thanks to Jeneral Sewer Service - George - 845-297-2285, a New York Hudson Valley drain and sewer cleaning and de-clogging expert for technical details and consulting on drain clog diagnosis and repair, including proper use of the Kinetic Water Ram for drain clearing - 3/14/2009
Thanks to our reader, Carole Cimitile, 2/17/2009, for reminding us that small problems like faucet o-rings, clogged faucet strainers and similar local plumbing fixture defects can have a big impact on hot water flow, cold water flow, or both hot and cold water flow and pressure problems.
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.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.
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