How do I Diagnose & Fix a Short Cycling Well Pump due to Well Piping Leaks?
Definitions of Well Pump Short Cycling vs Intermittent Cycling vs Loss of Water Pressure
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.
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
Question: My well pump is short cycling on and off but pressure in the building holds steady. I think I have a well pipe leak
I have been trouble shooting a problem with my well in my 100+ year old home over the last week and ... am asking for help in diagnosing the cause of short cycling of my water pump.
I first noticed short cycling of the pump (could hear the water hammer as pump shut off when in my well house which is also my shop) - The well would pump up to 68 psi and shut-off, then the pressure would rapidly drop to 38 and restart. I could hear water moving in the lines, but no faucets were on.
I then shut the valve upstream from the pressure tank (between the well, but before the gauge) and the pressure would hold steady (the house and all lines stayed pressurized until a faucet was opened). I figured the check valve must be out if it drained so rapidly, and I replaced the check valve, but the same problem was occurring.
So I noticed my pressure tank was pretty water logged and I drained off water, added back air to 38 psi, and turned back on the water supply.
That did significantly slow the cycling (from about every 15 seconds to now over a minute), but the pressure still drops when the pump clicks off. I am not having any problem with water pressure in the house lines (faucets/shower/etc).
[Our photo (left) shows a commercial type Square D 9013 Pumptrol pressure control switch. Courtesy of reader J.H.]
I am not getting any air out of any lines. I believe my well pump is working well, the pressure tank seems to be working well (with the addition of the air), I assume the foot valve is ok since I am not losing prime/pressure and I am not getting air.
I think I am dealing with a broken line/fitting underground between well/check valve and the house/pressure tank.
I have not seen any wet spots in the yard and I have been running pump all week (continues to cycle on-off about every 90 seconds). Any other ideas? Any recommendations on finding leak underground or just start digging.
-- J.H.
Reply: Here are some Diagnostic Tips that May Trace Down Short Pump Cycling to a Piping Leak
We are GUESSING from your description several things to check out or satisfy ourselves about, and I ask a few questions for clarification:
[Photo at left shows a Wellxtrol auxiliary water pressure tank. In this location a small pressure tank may also serve to reduce water hammer. The main water pressure tank for this system is shown at the top of This article .]]
It sounds as if you might have a leak (as you suggest) in the well line between foot valve (or submersible pump in the well?) and the house, possibly compounded by a waterlogged pressure tank (that you addressed). A leak will cause lost prime, can force air into plumbing lines, and can cause a water hammer sound when the pump comes on in some cases.
That rapid pressure drop after the pump shuts off is suggestive of a well line leak
We agree that shutting a valve between well and house piping and seeing that house pressure remained steady is a good indicator that the leak is upstream (towards the well) from that point. I infer that opening that valve and then opening a faucet in the house was allowing backflow of water and perhaps even air into the leaky line
The behavior suggests that water is falling back down the well line so your leak could be actually in the vertical piping inside the well casing.
Is your pump a submersible one in the well?If so that would be why you don't lose prime - the pump is self-priming in that location. And even if that pump's internal check valve is ok, a leak above the pump (towards the house) would still leak - either back into the well or into the ground - when the pump shuts off. And when the pump is on, in addition to sending water to the house it's spraying water out of the same leak opening.
The no air out of the lines is puzzling but perhaps if air is entering the leaky line and is later forced up towards the house it's so far a small volume and is trapped in the pressure tank - I've seen systems designed to actually work this way, forcing air back and forth to avoid freezing water lines that extended out into and deep down into a lake.
You wouldn't see wet spots in the yard if the well line leak is in the well casing or if the leak history has blown a cavity in the soil around the buried well line or if the line is deep enough, or if the line depth plus leak history have given an entirely-below-ground escape path for water forced out of the line when the pump is on. But you might see soil in your water - sucked into a leaky well line if the line leak point is in soil rather than in the well casing.
We suppose there could also be a leak at the pitless adapter
We think your next step is to pull the well line up and inspect it from within the casing - doubtless needing the help of a well plumber experienced with that step - don't lose anything down in the well.
Watch out: before you go to the trouble and expense of replacing a water pressure tank, make sure that you have correctly diagnosed the problem that you are "curing" - you wouldn't want to replace a water tank only to find that you still have the water pressure or quantity problem because another, perhaps less costly, part was at fault.
Next Steps in Well Pump Short Cycling Diagnosis and Repair - Well Piping Leaks
Yes I have a submersible pump and what you say about air and prime makes perfect sense.
I am going to start digging the well line near the well this weekend. I will take some pictures and keep you posted.
... snow finally melted here and I started digging up the yard....
I found the well line at near 38 inches deep, plastic water piping with 20 ft sections.
I already found one small well piping leak at a joint (not big) kept going, ended up uncovering nearly 250 ft of line and finally found the branch that goes out to my pool (another leak, but not huge).
So, I put in a shut off valve in that branch and turned on the system and was holding pressure and no cycling. [Photo at left]
So I fixed two small leaks, but I still have a big one out on pool line but now my house is up and running and no extra wear on my pump.
I was going to dig more this weekend but my back is not ready for the job yet! I will keep you posted and I have a guess that it is where there is a brass stop and waste that is hooked to the plastic pvc that is used to turn off the pool water in fall. It is in a very tough place to dig up, but I am guessing that is my trouble. Wish I would have started there!
But at least I got other leaks fixed and have another shut off valve in a water main that I can get my shoulders down in. Will let you know what I find when I take on the next task.
I will try and get more when I find the big leak.
Questions & Answers regarding this article
Questions & answers about well pipe leaks causing intermittent well pump cycling on and off..
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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. Quoting:
The Type FSG, FYG, FRG - PUMPTROL® Water Pump Pressure Switches are used to control Water Pump Pressure Switches are used to control
electrically driven water pumps and have the following features:
The Type FSG is the standard water pump switch, suitable for all types of pumps: jets, submersible,
reciprocating, etc.
The Type FYG is designed to meet higher horsepower and pressure requirements.
The Type FRG is reverse acting: the contacts open on falling pressure.
All are diaphragm actuated.
The Type G - PUMPTROL® Commercial/Light Industrial Pressure Switch is used to control electrically
driven water pumps and air compressors. It has higher electrical ratings for direct control of motors in
pump and compressor applications. The Type G switch is diaphragm actuated and has contacts that
open on rising pressure.
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