Two line jet pump diagram (C) Carson Dunlop Associates Diagnostic Guide to Well Pump Problems

  • WATER PUMP PROBLEM DIAGNOSTIC TABLE - CONTENTS: Diagnostic checklist in table form provices water pump problem identification, diagnostic steps, and repair steps. Deep-well Two Line Jet Pumps & Drinking Water Wells, Well Problems & Repair Advice. Shallow-well pump diagnosis and repair guide and checklist. What types of wells use a two-line jet pump for water delivery. Electric pump motor troubleshooting guide
  • POST a QUESTION or READ FAQs about how to figure out what's wrong with the well pump
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This article provides a table of diagnostic checks and procedures for fixing well water pump problems.

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Well Pump Troubleshooting Diagnostic Guide

Things to Check if the Well Pump Will Not Start

Pump Trouble Cause Diagnostic Procedure Repair Procedure
Electrical Power is Off 

Check that all service switches for the equipment are in the "on" position.

Check for voltage at the pump motor or pump controls. If no voltage is found, check for voltage at the electric panel.

If power is on to the building, check fuse or circuit breaker serving the electric motor that won't run.

Check for local reset button on the motor (popped out = off )

Check for other power reset or power off buttons such as an access door compartment safety switch that turns off power to the equipment (found on A/C blower compartment doors)

Turn on "off" switches.

Replace bad fuse. Reset circuit breaker; if necessary replace bad circuit breaker.

Let hot electric motor cool down, then push in its reset button.

Be sure all safety interlock switches such as on compartment doors are depressed and that the doors are securely shut.

Replace a bad safety switch.

Replace bad or damaged electrical wiring that shorted and tripped the breaker.




Blown fuse, tripped breaker

Replace fuse or breaker - does the pump run and keep running normally?

If the breaker keeps tripping most likely there is either a short circuit in the wiring or the pump motor is drawing abnormally high current

Be sure proper breaker or fuse size in ampacity is installed - ELECTRIC PANEL INSPECTION




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.

A loose wire can cause intermittent pump or other electrical device failiures as well as a hard failure that means no power or blown fuses.

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 motor control switch

Check the control switch contacts for burning or wear.

If the motor control is a well pump pressure control switch,check the pressure control switch settings - cut-in and cut-out; inspect for burned, pitted switch contacts or for dirt or wear.

For water pumps, 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 water pump control switch tubing

Clogged or leaky tubing connecting a water pump pressure control switch to the water system results in failure to properly sense and respond to water pressure.

Debris clogging can also occur in the bottom of the pressure control switch where it mounts or connects to the tubing.


Check and clear tubing blockage (blow air through tubing). Or install new tubing.

Be sure tubing is proper diameter and type to seal properly with other fittings.

Tighten tubing fittings to be sure there are no water or air leaks. Soap solution may help find air leaks in tubing fittings.

Clear or replace clogged pressure control switch if the bottom sensor opening is clogged and cannot be cleared.



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.


Other well pump troubles

If the Well Pump is too Noisy If the well or water pump has gotten quite noisy the cause may be a worn pump bearing or damage to the pump impeller.

Review our list of common sources of water pump noise before replacing anyhing.



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. Page top illustration courtesy of Carson Dunlop Associates.

Also see our other diagnostic guides for water pumps, wells, motors, in table form:


Continue reading at WATER PUMP REPAIR GUIDE which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WATER PUMP DIAGNOSTIC TABLE FAQs - questions & answers posted originally at this article

Or see WATER PUMP DIAGNOSTIC FAQs - other well pump Q&As

See WELL FLOW TEST PROCEDURE if your well runs out of water entirely

See WELL YIELD IMPROVEMENT to increase the yield (flow rate) of your well

Or see WELL WATER PRESSURE DIAGNOSIS to improve water pressure or flow rate

Suggested citation for this web page

WATER PUMP DIAGNOSTIC TABLE at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

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Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.

Recently posted questions & answers to this water pump diagnostic table article are provided below.

Also see WATER PUMP DIAGNOSTIC FAQs for questions & answers that help diagnose problems with water pumps or well pumps for the building water supply system.

On 2017-04-14 20:40:52.349901 by (mod) re: irrigation pump trips circuit breaker


A tripping circuit breaker on an irrigation pump circuit is usually caused by
- a pump motor that is overloading, seizing, failing or otherwise is damaged, drawing high current
- a short circuit in the pump system wiring

It's pretty easy to diagnose those conditions if the electrician is familiar with use of a DMM or VOM and can check the wires for shorts as well as checking the current draw of the pump. I suppose one of your timers could also be shorting.

Watch out: for electrical shock hazards - if you're not trained to do these steps I'd call an electrician.

On 2017-04-14 18:16:29.190488 by Bob

I have a 220v irrigation pump pulling from a lake. The pump is controlled by 2 Hunter timers separately wired to two hunter pump relays. The system has worked flawlessly for a couple of seasons. This season, something keeps tripping the breaker. I can start the timers manually and the pump will run through complete cycles. It might work automatically for a day or two but then I'll find that the breaker has tripped. I have been unable to determine if the trip occurs while the pump is running or on timer controlled startup. I have replaced the breaker and the wiring from the pump to the relays. I have checked the wiring in the relays and all are tight. This has not fixed the problem. Could a bad pump capacitor be the problem?

On 2017-04-12 16:03:40.409414 by (mod)


Short cycling will be observed right at the tap - the water pressure and flow will decliine then increase in rapid pulses of 15 seconds or less.

I suspect your pressure gauge and maybe pressure control switch are debris clogged.

On 2017-04-10 17:59:32.018269 by Jo

One more note, the pressure gauge was not all the way down to 30 when I turned on the breaker, and the pump kicked on. Could this be related?

On 2017-04-10 17:17:22.897027 by Jo

We just moved into a new house a few months back. It was a foreclosure, no one had been in it for a year and the water that came out at first was... dirty.
In the meantime, I started to notice that our power bill was double what we payed before. So I started testing, turned off the heat for a month and watching electricity usage. We went out of town, and decided to shut of breakers to most of the house, leaving on a few key ones such as water so that the someone could water animals, etc. I noticed that the electricity had only halved when we went out of town, so I re-examined the 3 breakers that we had not shut off. I shut off the water pump for a full 24 hours and my energy usage halved in that day, leading me to believe something is going on. After some calculations, and close observations, my water pump is using an average of 20KWH per day. There is only two adults in the house, both of which are out of the house for most of the day.
In addition, our electricity usage is significantly higher on "Laundry" Days. We do 3-4 loads. Not a little higher, much higher.
The pump is a submersible pump, and I am not sure how often it is running. On one hand I think it is short cycling because it is using more electricity when water is being used, but that doesn't explain the high electricity usage even when it is not being used (like when we went on vacation and the pets were given water once a day).
I then turned off the water pump for a few hours to see if the water pressure tank holds pressure. I waited overnight, and there is no change in pressure. I ran some water, which lowered the pressure in the tank, and then turned on the breaker. I watched the needle promptly return to 50PSI. Then I ran water again until it was about 40PSI and watched again. Nothing happened, the needle stayed in the same place.
I'm honestly just not sure where to go from here. Can you give any suggestions of what to check next?

On 2017-04-01 15:08:03.703109 by (mod)


I would start by checking or replacing the pump pressure control switch.

On 2017-04-01 14:42:03.441214 by (mod)


On 2017-04-01 14:41:48.490269 by (mod)


I'm not sure I understand the exact question. If you have a working well and pump then the pump Outlet which would normally feed a pressure tank could be connected to a temporary pressure tank and hose hook up that then could connect to your

On 2017-04-01 12:57:57.122306 by Elton

Woke up no water checked well good level of water pulled outside breaker near pump pushed it back in heard tank try to build pressure shut off after 5 seconds went in house had water for 2 to 3 seconds then dry again any suggestions

On 2017-04-01 12:25:03.995191 by Gary

How can I hook up a garden hose to my house since the pump burnt up? I have another well with power a few yards away.

On 2017-03-20 21:45:01.078948 by (mod)


Assuming no wiring errors it sounds as if either the pump is seized or the pump wiring is shorted together or to the casing.

Watch out: there are risks of death by electric shock.

If your pressure switch is controlling a second (heavier duty) pump relay control, there could be a failure therein - ahead of the pump - such as a shorted relay.

So that'd get checked.

But it's pretty easy (as I suspect you know) to check the pump wiring isolated from the switch or a control box: just disconnect the pump wires entirely at that point then check for continuity between them.

On 2017-03-20 20:34:35.990658 by Trudy

My 1/2 HP Single Phase - 3-wire 230V 6Amp submersible well pump in my 81 ft. well quit running; I started with replacing the pressure switch and cleaning out the pipe connecting it to the water line as pipe was 1/2 plugged, rewired same as old switch and when breakers turned on it made breakers crackle, etc. but not turn on the pump. Researched pressure switch wiring on mfg. website and rewired as shown, with the same thing happening. (Further research indicates both ways were correct.) Bought a new control box; same thing happening. With front off Control Box checked the voltage w/ a voltage tester at the breakers, at in lines at pressure switch, at out lines at pressure switch and at in lines at control box. All checked out 120V single line and 240V for both. With both the old and new Control Box fronts connected, pump does not run and the breakers crackle and fizzle, but do not when Control box front is off with wires still all connected up to Control Box with voltage readings correct; also plug in still working in pump house. Can I "assume" there is a short somewhere in the wiring inside the well or the pump motor at this point? Or................. Thanks!

On 2017-03-16 15:39:07.045894 by (mod)

Good going, Kristi! I love that diagnostic trick of tapping on the control.

Often debris or silt in the water supply can clog a pressure control switch. The first to clog is a very small orifice on the bottom of the switch through which water pressure is conveyed to a diaphraghm that in turn operates the switch. But debris can also clog the small-diameter tube on which some switches mount, or the tube that otherwise connects between a switch and the pump body or another system pressure source and the switch itself.

So if your water supply has mud, silt, debris that may be the underlying problem.

Of course there are other causes - found by searching for WATER PUMP WON'T START or for NO WATER PRESSURE

On 2017-03-16 14:37:24.730437 by Kristi P

We have a 1 HP Goulds SJ10 pump ( # C48A95A06) 2 days ago woke up to no water. Checked under the house for leaks, checked the pressure in the bladder tank, no issues. Replaced the Water Pump Pressure Switch and everything started working again. Water worked fine at 7 am this morning then no water again 2 hours later. (of course now my husband is at work!) Went out and tapped on the top of the pump itself and it immediately cut on! Any suggestions will be greatly appreciated!

On 2017-03-14 16:38:23.477307 by (mod)

I suspect that there is a failing pump motor, improper voltage, improper wiring, or wrong capacitor has been installed.

On 2017-03-14 12:33:23.935051 by Ed

Pump works fine for about 20 to 30 minutes, then the run capacitor burns out on the submersible motor control model number 2801084910.

On 2017-03-11 16:40:06.785650 by (mod)

Ask your plumber to check for lost pump prime, and if that's the problem, you probably need to replace a bad check valve or foot valve.

On 2017-03-11 16:05:09.753285 by Vicki

We had a power outage. When the power came back on, the water isn't pumping from our well. We have water for a few seconds from the faucet then it dies down. You can normally hear the faucet pulse/pump and we don't hear that either.

On 2017-03-10 03:25:49.115937 by (mod)

Please use the search box just above to search for PRIME THE WELL PUMP to see two priming methods one of which should work for you.
Also check for leaks in your well piping.

On 2017-03-09 19:45:47.221550 by Anonymous

I got all new 1 horespower pump pipe & foot valve. It 65 feet deep. And I can't get it to pump. Primed it many times and still nothing.

On 2017-03-02 17:08:49.984945 by (mod)

Search InspectApedia for LOST WATER PRESSURE to see diagnosis and repair procedures

On 2017-03-02 00:45:02.363655 by Amy

My well suddenly stopped pumping water. A couple days later it pumped water again for about a week and stopped again. The pump clicks on and then clicks off again.

On 2017-02-27 16:12:13.212061 by (mod)

Sounds like an overheating pump motor. Could be a failing bearing.

On 2017-02-27 15:22:59.344662 by Geoff

My Artesian well runs fine for around 5 minutes , then it trips the electric . If it is left for around 30 minutes it works again , then trips the electric again .

On 2017-02-15 21:00:09.344967 by (mod)

Submersible pumps don't normally lose prime as they're under-water. But you could have a leaky well pipe or check valve.

On 2017-02-14 02:28:42.409825 by Clyde

Pump runs to 60 lbs. and drops back to 40 lbs. I have water pressure and water but is my submersible pump loosing its prime, or is there another problem.

On 2017-01-27 01:29:38.897398 by (mod)

Anon: sorry if your post was deleted - I didn't do that on purpose but it might have happened by a too-hasty click.

Also when there are many questions at the end of an article we are sometimes forced to move them to an accompanying FAQs page - for page speed.


On 2017-01-27 01:12:50.765323 by Anonymous

Nice I posted for help with my jet pump only to come back n it's gone. Thanks for that whoever flagged it. Like my life ain't bad enough already. This just makes it worse. Now I know what to do to fix it

On 2017-01-23 18:35:15.655719 by (mod)

Look for a bad check- or foot- valve.

On 2017-01-23 15:47:40.054544 by Aldrin stein

Hi , my pump switches on and off after every 10 minutes without a tap being opened, I'm afraid the motor might burn out ?

On 2017-01-15 14:13:03.950088 by (mod)

I think you meant the pump will NOT achieve pressure over 20 psi.

Typical causes of that problem are in an article you can find by searching InspectApedia (use the search box just above) for WELL PUMP WON'T STOP RUNNING

for example : a damaged impeller, a piping leak, low water in the well

On 2017-01-15 00:17:11.984835 by -David

I have a jet pump which holds pressure to home but the pump will get over 20 psi ? The pump ran continuously until I lowered the cut off pressure. this is the 3rd pump from Home Depot over a period of 5 years that I have tried. Would it just be a poor pump design.

On 2017-01-13 19:11:19.934764 by Mike

I have a sub pump I have very little pressure I replaced contacts checked pressure on holding tank (28lbs) I check voltage ok(240) can see water in filter when I turn pump on pressure gauge stops at 20lbs could gauge be bad pump run all the time help!

On 2017-01-13 04:38:54.683474 by (mod)

If the sound is from an electrical problem the installation is very unsafe and should be left turned off. Do you smell smoke or see Sparks?

Another possibility is mineral deposits or debris inside the impeller of the pump assembly.

On 2017-01-13 02:20:40.161909 by connie joiner

Well water pump makeing a popping sound.!!! What will cause thst?

On 2017-01-12 16:54:53.223136 by (mod)

A short between well wires, short from well wires to well casing, short to ground, seized well pump motor, frozen pump contactor switch. Or less likely: a defective breaker.

Watch out, there are harzards of death by electrocution: leave the circuit off and call for repair by an electrician. It should be easy to use a VOM or DMM to check the current draw and grounding and continuity on the circuit as part of diagnosis.

On 2017-01-12 16:38:27.510247 by Richard

My well pump keeps blowing the circuit breaker what could be wrong


(May 23, 2011) Anonymous said:
This guide was the perfect answer to our problem. Thank you so much for this donation of knowledge.


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