Well pump on-off rapid cycling diagnostic table:
This well pump problem table describes the steps to diagnose and cure all known causes of well pump short cycling - what causes the well pump to run too often.
Here is a table of all known causes of well pump rapid cycling. For each cause the table provides a diagnostic procedure and recommends a repair procedure.
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Short cycling of a water pump (which is discussed in this article) means that the water pump turns on and off too rapidly or too frequently when water is being run in the building.
If this is the problem with your water pump, you can use the diagnostic table below or for more explanation see our description of the most
common WATER PUMP SHORT CYCLING CAUSES.
If you are not sure what "water pump short cycling" means or how it is recognized,
see SHORT CYCLING WATER PUMP.
Well Pump Short Cycling Diagnosis: Things to Check if the Well Pump Runs Too Often
|Pump Trouble Cause or Symptom||Diagnostic Procedure||Repair Procedure|
Diagnose Three Different Water Delivery Problems
|Short cycling water or well pump explanation||Read in depth on causes and cures of well pump short cycling on and off - the link at right is an alternative to using this more concise diagnostic table (below).||See the diagnostic article
at WATER PUMP SHORT CYCLING CAUSES
|Intermittent water pressure explanation||The water pump sometimes runs for no apparent reason at all, when no water appears to be running, but the pump is not cycling on and off rapidly - it just comes on and goes through a cycle at odd times.||See the diagnostic article
at INTERMITTENT CYCLING WATER PUMPS
|Lost water pressure||Water pressure is poor or has stopped completely|
Table of Detailed Water Delivery Problem Troubleshooting Procedures
|Pump Trouble Cause or Symptom||Diagnostic Procedure||Repair Procedure|
|Air discharge at plumbing fixtures||
Inspect the air volume controls, snifter valves, automatic air insertion devices on the water pressure tank if your water tank does not use an internal bladder.
Inspect for a ruptured bladder or an older air volume control or snifter valve that should have been removed when the bladder-type tank was installed.
|See AIR DISCHARGE at FAUCETS, FIXTURES|
|Water pressure tank leaks
Loss of air charge in the water tank
Inspect the water pressure tank for obvious perforations or severe rusting.
Apply soapy water to the entire surface of the water tank, especially above the water line. You can spot the water line as the high point of condensation on the water tank exterior.
Remember to check also for leaks at the air valve(s) used to pump air into the pressure tank.
Temporary repair of a rust-perforation of a non-bladder type water tank may be possible using a sheet metal screw and neoprene or rubber washer. But the tank needs replacement.
Note that for water tanks that do not use an internal bladder the air charge is gradually lost to absorption into water passing through the tank.
|Pinhole leak in water pressure tank bladder||
Water-logged internal-bladder type pressure tank with a pinhole leak in the bladder may accumulate water inside the bottom of the tank (where air should be) and thus cause water pump short cycling.
But because water leaks into the tank's air space just at higher tank pressurs and does not easily leak back into the pinholed bladder (where water should be in most designs) when we depress the air valve atop the tank it may not squirt water -just air.
If the tank is abnormally heavy even when drained we suspect this problem.
|Water pressure tank bladder damage or leak||
If the pressure tank is a "captive air" or internal bladder type tank, a leaky or damaged bladder can cause the water tank to become waterlogged and cause short cycling of the water pump.
Most bladder type water tanks contain water inside the bladder and air outside it. Be sure you checked the tank for apparent leaks as we described in the step above.
If your bladder type water tank is fiberglass it may be reversed in design, containing air in the bladder and water in the tank. Still a damaged bladder leads to a waterlogged tank.
A leaky or damaged water tank bladder needs to be replaced or the entire assembly replaced.
|Defective or leaky Air Volume Control||
A leaky or failed air volume control (AVC) will lead to a waterlogged water tank as the control is no longer doing its job of maintaining the tank's air charge. (Not all water tanks have an AVC).
Inspect the AVC and its tubing for rust or water leaks. But an air leak may also be present - see our next step below.
Repair or replace any suspect air volume control components.
Optionally, remove and plug the AVC fittings and change to an alternative method of maintaining the air charge in the pressure tank:
Use the water tank air inlet valve - details are at WATER TANK AIR INLET VALVE
Drain the water tank - details are at WATER TANK AIR ADD BY DRAINING
|Air volume control tubing leak:||Disconnect the air volume control at the water pump and plug that opening. If the water capacity improves there is probably a leak in the tubing or the control.||
Tighten all tubing fittings, be sure the tubing is correct diameter and proper fittings are used so that there are no air or water leaks.
|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. See
PUMP PRESSURE CONTROL REPLACE
|Manual reset required on some pump pressure controls||If your pump has an electrical low water protection device that component may shut down the pump to protect it from damage if well water level or flow rate falls too low. That pressure control switch may shut down the pump and require manual re-setting||WATER PUMP PROTECTION SWITCH|
|Bad pump pressure control switch tubing||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. See
PUMP PRESSURE CONTROL REPAIR
|Bad pump pressure control switch settings||
Especially if someone has been fooling around with the pump pressure control cut-in and cut-out pressure settings, the difference between the cut-in (low) and cut-out (high) pressures may be set too small.
Check the water pressure as the pump cuts in and again as it cuts off.
Typically we see about 20 psi difference between the pump cut-in and pump cut-out pressures. If you are finding less than this, adjust the pressure control switch accordingly. See
Watch out: Don't set the cut-out pressure too high or the pump will just keep running. Also, pump gauges are not always accurate. You may need to use a static pressure gauge on a nearby hose fitting such as for the washing machine. See WATER PRESSURE GAUGE ACCURACY
|Bad water pump, pump start capacitor, or pump controls||
Especially if the water pump has been suffering a prolonged history of rapid short-cycling on and off or if a pump motor is old, worn, hard-starting, or has failing bearings, the pump's electrical controls such as a start capacitor used on some pump motors may have failed.
Thanks to reader M.H. for this tip 7/23/14
Check for a pump drawing abnormally high curreint - signs of wear or motor failure.
Check for a bad start capacitor.
|Bad water pressure tank location||Locating the water pressure tank too far from or on a different level from the pressure control switch can cause pressure control switch bouncing and rapid water pump on-off cycling at the start or end of a water pump operating cycle.||See Where to Locate the Replacement Water Pressure Tank|
|Water Pressure Tank Frozen||Frozen water pipes at the outlet of a water pressure tank or a frozen water pressure tank outlet tee, or a frozen water pressure tank itself can all case water pump short cycling.||Details describing this problem, its occurrence and repair are
at WATER TANK or TANK TEE FROZEN
|Blocked water piping, clogged water filter or other water treatment equipment||A blocked or clogged water filter or pipe or other water treatment equipment close to the water pressure tank can cause very rapid on-off cycling of the water pump, particularly if the filter, valve, or equipment is located between the water pump and the water pressure tank.||
Check the order of installation of equipment. Be sure at least one clear water piping pathway is open between the water pump outlet side and the water pressure tank inlet side.
Replace a dirty, clogged, or suspect water filter cartridge.
Watch out: turn off the pump right away to avoid damage.
|Closed or partly closed water supply valve||Be sure that you haven't forgotten and left a valve closed between the water pump and water pressure tank. This can happen if someone closes a valve to perform other work on the plumbing system and forgets to open it again.||
Be sure at least one clear water piping pathway is open between the water pump outlet side and the water pressure tank inlet side.
Watch out: turn off the pump right away to avoid damage.
|Plumbing piping or fixture leak on the discharge or supply side of the system||
A plumbing supply piping leak or running toilet can lead to frequent cycling of the water pump.
Shut off all of the fixtures in the plumbing system at their local shutoff valves. If no shut off valves are installed or if they are stuck, install or repair them at the next opportunity.
Listen for leaks. Check for running toilets by using a small amount of food coloring or septic dye dye in the toilet tank. If colored water appears in the bowl the toilet flush valve is leaking.
Repair any plumbing leaks or leaky fixtures.
|Piping or fitting leak on the suction side or well side of the system||
A leak in the well supply piping anywhere between the water pick-up point in the well bottom and the entry to the water pressure tank can cause loss of water pressure and water pump short cycling. (It can also cause air entry into the piping system).
For shallow wells install a pressure gauge on the suction side of the system.
If your well is a deep well (2-line jet pump) install a pressure gauge on the pump if an attachment point is available.
Let the pump run until it reaches its cut-off pressure. Note the pressure on the gauge.
Turn off power to the pump. Turn off water leaving the pressure tank and feeding the building - the valve on the "discharge" side of the system.
Alternatively, after closing the water valve on the output or discharge side of the system (stop feeding water to the building), use a bicycle pump to pump air into the system at the air inlet valve (if your system has one).
Pump to 30 psi.
Watch for a pressure drop. If the system won't hold pressure then there is ale a leak on the "suction side" of the water system.
Leaks may be a bad check valve, foot valve, or piping connection anywhere between the pressure tank and well bottom.
At AIR DISCHARGE at FAUCETS, FIXTURES
First check and tighten all above-ground well piping connections to be sure nothing is leaking. Remember to check or replace any above-ground check valves that may be leaking.
Repeat the test.
If the system still won't hold pressure you will need to pull the well piping and check for a defective or leaky piping connection, leaky well piping check valve above ground, at the pump (if there is a valve there) or in the well at the foot valve.
|Leaking foot valve in the well or leaking check valve at the pump||If the well pump frequently loses prime, there may be a leaky or failed check valve (at the pump) or foot valve (in the well).||
If your jet pump (above ground) incorporates a check valve at or in the pump that valve may have failed.
If there is no foot valve in the well (or if that valve doesn't work), the failure of the above-ground check valve at the pump can lead to short cycling or to loss of pump prime.
To examine the foot valve the well piping has to be pulled.
For this reason if you do pull the well piping we recommend replacing the foot valve rather than having to repeat this procedure again soon.
Remember to inspect the piping, connections, tailpiece, ejector, and all components in the well.
|Pressure control switch differential adjustment too small||
Water pump turns on and off too frequently when water is being run in the building
Pressure control switch adjusted incorrectly: Differential too small
Note: in a different problem case, setting the differential range too small combined with a high cut-out pressure on some pressure control switches can cause the water pump to run continuously.
In adjusting the pressure control switch differential nut#2, if you completely loosened the smaller nut #2 (differential adjustment) so that the pump differential between cut-in pressure and cut-out pressure is very small the water pump may short cycle on and off rapidly when water is being run in the building.
Re-adjust the pressure control switch.
|Short cycle stop valve stopped working||If a well pump short cycling cycle stop valve has been installed and the system is relying on this device to cure a well pump cycling on and off too often, check that the valve is installed correctly and is working properly.||See SHORT CYCLE STOP VALVE|
Well Pump Wiring Problems
blown fuses, tripped breakers, low pump output
Well pump keeps tripping circuit breaker or blowing fuses, or well pump fails to deliver water at normal flow rate and pressure.
Look for low supply voltage, burned control switch contacts, damaged well pump wiring, or a damaged well pump itself.
A recent lightning strike can also damage well pumps or wiring leading to these symptoms.
|If the Well Pump Motor Runs for no apparent reason||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.
|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 causes of well pump short cycling that we have not mentioned: ask your plumber. And CONTACT us to add that helpful information for others.
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.
CONTACT us by email with questions or suggestions about this list.
Short cycling of a water pump which is defined at SHORT CYCLING WATER PUMP means that the water pump or "well pump" turns on and off too rapidly or too frequently when water is being run in the building.
If this is the problem with your water pump,
SHORT CYCLING CAUSES describes the most common causes of this problem.
If you are not sure what "water pump short cycling" means or how it is recognized,
read SHORT CYCLING WATER PUMP.
Intermittent water pump cycling which is discussed
at INTERMITTENT WATER PUMP CYCLING means that the water pump comes on for no apparent reason.
Loss of water pressure means that the pressure with which water enters a plumbing fixture has become too slow, or is sometimes too slow or weak in water flow rate, or water flow may stop entirely.
Continue reading at WATER PUMP SHORT CYCLING - PIPE LEAK or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see SHORT CYCLING WATER PUMP - home
Or see WATER PUMP INTERMITTENT CYCLING - pump runs for no reason
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(Oct 11, 2014) Shawn said:
I have a deep well pump that seems to be short cycling? I have a peroxide system tied into it which brought the problem to my attention. I could hear that system coming on and off. I thought that was my problem and had the company out here to service it and
they noted that the pressure would come up and drop off immediately and then recycle a number of times till it finally held. This happened after they drained some water from the line. They suggested it might be the well pump or check valve. Pump is a submersible.
I have changed the filter in the whole house filter seeing if that would solve the problem. It did not seem too. My next thought is to change the pressure switch. I don't believe that has been changed since house was built in 2006. But because of the nature of my water supply (heavy sulfur content) the pressure tank has been changed out 3 times. The current pressure tank is now a fiberglass and not a metal and was changed out 2 years ago. Do you have any thoughts on this problem?
(Dec 3, 2014) linda said:
If there is a 2 year old well pump and there are no leaks what causes a pump to keep kicking on?
An explanation and suggested solutions are in SHORT CYCLING WATER PUMP. Please take a look there and then let me know if questions remain. Thanks.
(Oct 22, 2014) Sherry said:
Thanks so much! Well pump was short cycling and getting hot. I shut off the breaker to cool motor down and googled you. I saw the suggestion for the clogged filter on you problem table.. I had filters so swapped it out and ......it seems to have solved it. Thanks so much for helping solve the problem and saving me the money of a repairman.
Linda: you'll want to see INTERMITTENT CYCLING WATER PUMPS
(Oct 25, 2014) Tony said:
We have a 4 kw pump for a sprinkler system, we have recently added a new connection to the water supply to fill a tank if we run the sprinklers and fill the tank simultaneously or the sprinklers on their own no problem. If we try to fill the tank without the sprinkler system the pump short cycles
(Nov 6, 2014) Bob said:
Water comes out of air fill valve when pushed does that indicate bladder broken inside?
Most likely yes, Bob. You'll need to replace the bladder or the whole tank assembly.
Bob as long as your water pressure tank tank is a typical internal bladder model that stores water in the bladder and air around it.
3 March 20915 Scott said:
I'm having an issue with my pump pressure switch bouncing at the end of the pump cycle (after reaching the cut-off pressure). It cuts on and the pump works to refill the tank/lines, but once it reaches the cut-off pressure, it stops momentarily, then begins to turn on and off repeatedly and rapidly (I disconnect the power when this happens to avoid further damage to the pump). I suspected a bad pressure switch and replaced it, but the issue remains. I've drained the pressure tank of water, and adjusted the pressure to the recommended 28PSI. I've also checked the small tube that connects to the switch for debris build up, but it's clean. What's the next step for troubleshooting?
When I see this I check for burned pressure switch contacts - which means replace the switch if that's what you find. If the switch is not burned then check for debris clogging in the mounting tube or switch sensor input port. Last and least likely is a water hammer problem.
Thanks for the info, Dan. I've already replaced the pressure switch and checked the mounting tube and switch sensor input port. Can you describe the water hammer problem?
Water hammer is discussed at
sometimes a pump shutting off can cause water hammer in the pipes that might cause a bit of pressure surging - but frankly I suspect the trouble is elsewhere.
CHeck that there's not a nearly-clogged water filter on the system or a blockage into the pressure tank.
Double check wiring throughout to be sure there's no loose connection.
Yes, I don't think I'm seeing any of the other symptoms of water hammer, so most likely another issue. I do suspect there might be a blockage into the pressure tank... is that common? When the problem first occurred a few days ago, I was able to leave the pump unplugged and had enough water and pressure to take a quick shower. Now, the water is running out much faster. When I rock the pressure tank, it doesn't seem as full as it was a few days ago, even after running the pump until it reaches the cut off pressure. I had someone else looking at it, and they thought the problem might be a bad check valve between the aerator tank and the pump (water from the aerator tank is drawn to the pump and then sent to the pressure tank and on to the house plumbing). Which direction should the check valve be preventing the water from flowing? It should stop water from flowing back into the aerator tank, correct? There is also another check valve on the line from the pump to the pressure tank. The person I had looking at it said that it was unnecessary and recommended removing it.
Questions & answers or comments about troubleshooting well pumps that turn on and off too often - short cycling water pumps.
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