Complete Diagnostic Guide for Water Pump Short Cycling

SHORT CYCLING DIAGNOSIS TABLE - Table of all known well pump short cycling causes & diagnostic & repair steps
- What causes the water pump to turn on and off too often or too rapidly?
- How to diagnose & correct short cycling "on-off" of the building water pump
SHORT CYCLING WATER PUMP - separate article

SHORT CYCLING CAUSES - separate article
SHORT CYCLING due to PIPE LEAK - separate article
WATER TANK AIR, HOW TO ADD - separate article
WATER PUMP PRESSURE CONTROL SWITCH - separate article

Questions & Answers about troubleshooting well pumps that turn on and off too often - short cycling water pumps
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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.

Well Pump Short Cycling Diagnostic Guide - What to Check, How to Fix

WellMate fiberglass water pressure tank (C) D Friedman J Hafner

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, see our description of the most common SHORT CYCLING CAUSES.

Here we provide a complete SHORT CYCLING DIAGNOSIS TABLE of all known causes of well pump rapid cycling. For each cause the table provides a diagnostic procedure and recommends a repair procedure.

If you are not sure what "water pump short cycling" means or how it is recognized, see SHORT CYCLING WATER PUMP.

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.

Well Pump Short Cycling Diagnosis: Things to Check if the Well Pump Runs Too Often
Pump Trouble Cause	Diagnostic Procedure	Repair Procedure
Short cycling water or well pump explanation	Read in depth on causes and cures of well pump short cycling on and off - alternative to using this more concise diagnostic table (below).	See the diagnostic article at 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	See WATER PRESSURE LOSS DIAGNOSIS & REPAIR
Water pressure tank leak, loss of air charge	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. See Well Tank relation to Water Pressure Shaking the Water Tank? - is it full of water? WATER TANK AIR VALVE REPAIRS.
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. See Bladder type Water Tank Failures and Repair for Burst Tank Bladder
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. See WATER TANK AIR VOLUME CONTROLS 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. See WATER TANK AIR VOLUME CONTROLS
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 WATER PUMP PRESSURE CONTROL SWITCH PRESSURE GAUGES PRESSURE GAUGE ACCURACY PUMP PRESSURE CONTROL ADJUSTMENT PUMP PRESSURE CONTROL REPAIR PUMP PRESSURE CONTROL REPLACE
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 WATER PUMP PRESSURE CONTROL SWITCH PRESSURE GAUGES PRESSURE GAUGE ACCURACY PUMP PRESSURE CONTROL ADJUSTMENT 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 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
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. See WATER FILTERS and CLOGGED SUPPLY PIPING. 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. See Turning on Water when de-winterizing Water Supply/Drain Pipe Leak Types PIPING IN BUILDINGS, Clogs Leaks Types See WELL PIPING LEAK DIAGNOSIS
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 and at SHORT CYCLING CAUSES we discuss the role of a bad check valve or a hole in the well piping in causing well pump short cycling - water and pressure are lost through the leak when the pump runs, and air may enter the piping when the pump stops - depending on where the leak is located. 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. See WELL PIPING LEAK DIAGNOSIS and AIR DISCHARGE at FAUCETS, FIXTURES WELL PIPING FOOT VALVES WELL PIPING TAIL PIECE CHECK VALVES, WATER SUPPLY WATER PUMP PRIMING PROCEDURE
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. See SHORT CYCLING CAUSE: WELL PIPE LEAKS WELL PIPING FOOT VALVES WELL PIPING TAIL PIECE CHECK VALVES, WATER SUPPLY WELL PIPING LEAK DIAGNOSIS
Short cycle stop valve stopped working	If a well pump short cycleing 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
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. See WATER PUMP WONT STOP RUNNING and WELL PIPING LEAK DIAGNOSIS
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.

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. We also provide a complete SHORT CYCLING DIAGNOSIS TABLE that lists all possible causes of well pump rapid cycling on and off. 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 When No Water is Running 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. See WATER PRESSURE LOSS DIAGNOSIS & REPAIR

Readers of this document should also see these diagnostic guides for water pumps, wells, motors:

ELECTRIC MOTOR DIAGNOSTIC GUIDE - table format and text.
WATER PRESSURE PROBLEM DIAGNOSIS TABLE - table format. Also see WATER PRESSURE LOSS DIAGNOSIS & REPAIR - text.
WATER PUMP PROBLEM DIAGNOSTIC TABLE - table format. Also see WATER PUMP PROBLEM DIAGNOSTIC TABLE - text

Readers of this document should see WATER PUMP TYPES & LIFE EXPECTANCY, and also see WATER TANK LIFE EXPECTANCY and WELL LIFE EXPECTANCY, but before assuming that a water problem is due to the pump or well itself, see Water pump and pressure tank repair diagnosis & cost a specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost.

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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
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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 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
Pumptrol® Pressure Switch Adjustment, Square D, Schneider Electric Corporation, 8001 Knightdale Blvd., Knightdale< NC 27545 1-888-778-2733 - Square D Technical Library, web search 07/24/2010 original source: http://ecatalog.squared.com/techlib/docdetail.cfm?oid=09008926800a93be
9013 Pumptrol® Commercial Pressure Switches Type F and 9013 Commercial Pressure Switches Type G, Catalog, SquareD, Schneider Electric Industries SAS, Schneider Electric Industries SAS, web search 02/23/2011, original source: http://ecatalog.squared.com/pubs/Machine Control/
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Square D is a brand of Schneider Electric.
Class 9013 Square D Commercial Pressure Switches: Water Pump Pressure Control Switch Class 9013, Type F, G, Manual, Square D Company, 8001 Highway 64 East, Knightdale, NC 27545-9023, USA, (919) 266-3671, www.squared.com, web search 02/24/2011, original source: stevenengineering.com/tech_support/PDFs/45COM.pdf.
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