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WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER CONSERVATION MEASURES
WATER CONTAMINANT LEVELS
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL CHLORINATION & DISINFECTION
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
How to set the air pressure in a water tank using an internal bladder: this article describes how to determine the proper air pressure setting in a bladder-type well tank, when, and how to actually change the air pressure in the water tank. We explain how to determine the proper air charge for water pressure tank and how to adjust the actual tank air pressure to that number. We detail how to fine tune the water pressure tank air charge to match the pump pressure control switch settings.
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Readers of this document should also see Water pump and pressure tank repair diagnosis & cost an specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost. The page top photo shows the author testing the air pressure in a Well-X-Trol bladder type well tank.
[Click to enlarge any image]
According to Well-X-Trol, bladder type well tank air precharge: typical factory set air pressure on a bladder-type residential well water tank is 18 psi. Some models may come with different pressure settings however. WELL-X-TROL™ water pressure tanks are shipped from the factory with a standard precharge of
Before discussing doing anything to a bladder-type water pressure tank, read this safety warning from WELL-X-TROL, a leading well tank manufacturer:
DANGER! [Water Pressure Tank] EXPLOSION HAZARD
WHEN THE WELL-X-TROL HAS BEEN IN SERVICE AND A CHANGE TO A HIGHER PRE-CHARGE PRESSURE IS NECESSARY DUE TO A REQUIRED CHANGE IN THE PRESSURE SWITCH SETTING, FAILURE TO FOLLOW INSTRUCTIONS BELOW CAN CAUSE A RUPTURE OR EXPLOSION, POSSIBLY CAUSING SERIOUS OR FATAL PERSONAL INJURY, AND/OR PROPERTY DAMAGE.
If you are fine-tuning water tank bladder or air pressure be sure that you are using an accurate pressure gauge and that you know how to obtain an accurate pressure reading. See WATER PRESSURE GAUGE ACCURACY for details.
Set the well tank air pressure to 2 psi below the well pump control switch cut-in pressure.
Remember to use your separate air pressure (tire) gauge to check the actual water tank pressure when your well pump turns on and off - that's because the dial gauge installed on your water tank may be inaccurate.
If you need to tune your bladder-type water tank to work exactly properly with your pump pressure control switch, or if you know that someone has already modified the pressure in your water tank and you want to restore it to factory specifications, a reasonable procedure is the following recommended by the manufacturer:
Well-X-Trol offers excellent advice on adjusting the water pressure control switch which we paraphrase, edit, and expand below:
Because well pump pressure control switches are not precise, "lab grade" instruments, the actual pressures at which a pump control switch turn the pump on or off will sometimes be above or below the stated pressure setting on the package of the control switch or above or below the pressure range shown on the switch itself (if your switch has such markings, most do not).
A difference between the marked pressure settings on a control switch and its actual performance can cause a
We want to adjust the water pump pressure switch to be"tuned to the Well-X-Trol (or other brand) bladder-type water tank air pressure that was set at the factory (or is presently the actual pressure in the tank). Here is the procedure:
Frequently-Asked Questions (FAQs) on internal-bladder water pressure tanks & draw-down water volume, pressure switch adjustment, and proper air pre-charge pressure
Question: what is the relationship of water tank rated size to actual water draw-down volume?
How much water should be in the water pressure tank intenral bladder? The water tanks are rated as 85 gallons. When the system cut-out water pressure is reached there is only about 5gal in tanks? - Stephen
Reply: Table of Water Tank Draw-Down vs Rated Size
Modern internal bladder type water pressure tanks give an "equivalent draw down" cycle to the actual "gallons" number on the equipment, but the actual physical volume of water may be significantly less.
5 Gallons does not sound reasonable. Typically on an "85 gallon" sized water tank, the actual water draw-down volume will be about 25 gallons. Below we include a table of rough estimates of actual water draw down volumes for different internal bladder water pressure tanks.
Notes to the water tank draw-down volume table above:
Detailed Chart of Water Pressure Tank Sizing, Tank Volume, Water Drawdown Gallons
Notes to the Wel-Rite Water Tank Sizing Chart
Data based on a Well-Rite® water pressure tank 
When choosing an internal-bladder type water pressure tank, take note of the operating pressure range of your well pump equipment. You will see in the table above that the higher you set the water pressure cut-in and cut-out, the smaller will be the draw-down volume provided by a particular water pressure tank.
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Frequently Asked Questions (FAQs) about setting the air pressure level in water pressure tanks
Question: short cycling well problems fixed by reading this article - thanks
Problem: Pump cycling every few minutes for months....Your question and answers solved my blatter type pressure tank cycling problem. I drained the tank and added air to 28 psi (was below 20 psi). I filled/pressurized tank and adjusted limits to 30 (low) and 50 (high). And WOW, now it takes 5 toilet flushings before pump kicks on. I tested the pressure tank psi after pump clicked off and my guage read 53 psi. So my problem was low air in the pressure tank and limits out of adjustment. Thanks for your instructions that anyone can follow and it saved me lots of money for a plumber. - Bob 8/21/11
Bob: Thanks for the nice note; we work hard to make our information useful and unbiased; I'm thrilled it worked for you; we continue to welcome questions or suggestions for our content as together we're smarter than working alone.
Question: water pump is short cycling - I have no idea where to start
Ok so I have a few problems here. First off my pump is short cycling drastically as in I flush my toilet and within 3-4 seconds I hear the pump kick on. Second, when it kicks on it only stays on for a few seconds before turning off then it only stays off for a couple more seconds before turning back on.
And recently about once a day or once every couple days the pump wont come on at all and I have to go down and tap the pressure control switch housing for it to come on. By the time I realize that, we have pretty much lost all pressure in the house due to normal use. I haven't quite nailed down any tying reasons or times when this happens like my wife doing laundry or something along those lines.
When the pump is working we have plenty of pressure, almost too much (water sprays out hard and makes a mess when doin dishes lol). I have looked through this site and have found a bunch of useful information but am overwhelmed and don't have a clue where to start. Any guidance in this matter would be greatly appreciated. - Mark 9/23/11
Live links to those artilces are in the Related Links section near the top of this page.
Question: replaced pressure control switch - do I need to change the tank pre-charge pressure?
I have a 20 gal wellxtrol with a 30-50 psi squareD pumptrol switch with pressure reading that are unusual. The pressure switch needed replacing because contacts were sticking. I put in a new pressure gauge and measured before I replaced the switch: tank pressure 18 psi, cut in 42 psi, cut out 67 psi. The system seems to work fine. It's 25 years old. I replaced the switch with the same, and adjusted it to 38 psi cutin, 64 psi cut out. Do I need to increase the tank pressure to 36 psi? Should I be using a 30-50 psi switch when running 38-64 psi cutin-cutout? - D Harry 10/28/11
Question: water dripping from water pressure tank gauge
i need to know what the ptoblem might be if there is water dripping from the water gauge where the floast is on the water tank - Robin 11/27/11
Robin it sounds as if your gauge mount is leaking or the gauge itself has failed internally and is leaking from the gauge assembly. It should be possible to purchase a new part and using pipe dope, teflon tape, or teflon pipe sealant, replace the part and seal the leak. You'll need to turn off the pump, drain pressure from the system (you don't need to fully drain the system) to install the new part.
Question: how long for water pressure to return after bleeding the pressure tank?
how long should it take to have well water pressure back after bleeding and reseting? - Matt 12/30/11
Reply: one pump "on" cycle
Question: do I need to verify the factory-set air pressure in my water pressure tank - will that fix bad house water pressure?
I have a Well-X Trol (size to be verified tonight)pressure tank.
Reply: no, no.
Question: short cycling pump troubles
I need assistance with my short cycling problem. Woke up one morning to no water. Removed the cover from pressure switch and the contacts touched, pump started running , but only a few seconds, contacts separated again. I held them shut manually and the pump ran as long as the contacts were shut, but when I released it they opened again. Bought a new switch, installed it and now all it does is on and off, on and off the entire time that water is running. But I noticed that the pressure guage stays at 40 all the time, never moves.
So I checked the air in the tank with a tire guage , and it read 30 psi. I did not drain it yet to check it. I am waiting on an answer from you before I do that. If I tap on the tank, it sounds hollow at the top 1/3 of it, and the bottom sounds solid. So I don't know what the cut in /cut out is set at, because the guage does not move at all. I don't know where to start at to try to diagnose this. I can't call a plumber because I am disabled and can't afford it, so I have been getting alot of knowledge from your site. PLEASE HELP ME, I have to get this repaired asap, I have 2 children living here, 2 year old and an 11 month old. I am mechanically inclined, just need to get an idea where to start. Any ideas for me?
Lisa, over at WATER PUMP SHORT CYCLING you can read how to diagnose and fix the trouble.
Question: shared well, lost power, but water doesn't make it up to my house
Hello I have a well shared with a neighbor my well is located down at the bottom of my property I lost power lines wrecked by downed trees underground now power provided by neighbor moved pressure tank and pressure switch to well site as needed for power 85 gallon tank replaced 30/50 with 40/60 switch neighbor gets plenty of water now does not make it up hill get air and that's all will reset tank pressure to 38 any other suggestions has to climb hill 400 ft plus to my house? - Lloyd 4/5/12
Moving the tank and switch downhill to the neighbor probably means that the output pressure of that equpment isn't enough to push water uphill to your house.
Lee Dilkie said:
Question: pump doesn't shut off, now no water pressure
First I noticed water pump was not shutting off, went to check pump it was hot so Shut off pwere to pump, shut off till pump cooled turned back on , no water pressure and pump would not shut off, cleaned points , did not do any good, I get water when turned on not much about 22psi.. should be at about 40psi for my well, please help.. - Ruby Berarducci 4/28/12
When a pump runs continuously and there is no water pressure you may have any of several possible causes such has an exhausted well, well piping leak, or damaged pump.
Question:40-60 pressure switch with bladder air tanks.
Can i use a 40-60 pressure switch with bladder air tanks. Your tanks are rated at 50 PSI max. Is this bladder pressure of water pressure. Thank you - Tom Renzo 4/28/12
Yes but you have to set the pressure cut-out down to 50 psi. Drop the cut-in to 30 psi and you'll be OK.
Question: how do I get 100 psi of water pressure in my home?
How can get a bladder tank constantly produce 100psi pressure? - Pete 5/5/12
Reply: you don't
Pete, you can't. A home residential water supply system is not intended to operate in that pressure range and would be unsafe.
Question: pump runs continuosly when our sprinkler system is on
I have a WX-250 that comes shipped with 30psi, I have filled it to 38, the switch is a 40/60 should the pump continually run when sprinkler systems are going? - Susan 6/2/12
Susan if the water draw rate from your sprinkler in gpm exceeds what the pump and/or well can deliver, the pump may run continuously. Check first that there is no hidden leak in your sprinker system piping.
Question: well pump relay clicking clicking clicking
i have a flotec fp4012 water pump which i wated to install and did but it filled the tank and had water in the house but after it fill it would try to fill more would click so i shut it off and put the old pump back in any help or idea would be great thanks jim - James Duham3el 6/2/12
It sounds like a bad pressure switch or clogged sensor port on the switch body
Question: gauge always says there is 50 psi, pump keeps turning on and off
My pressure gauge always says there is 50 psi in the tank, no matter what. But the well pump is short cycling.
Lisa, first, you have a bad pressure gauge. Second, you have a bad pressure tank. Turn the power to the well off, drain all water from the tank, and then check the air in the bladder. It should be 2 psi below the cut-in pressure of the pressure switch (38 psi for a 40/60 switch). If it is very low, and I'm sure it will be, you can add air to it to try and get by for a while but you are only delaying the inevitable. The low air in the bladder is taking away from your draw down, or the amount of water you can draw before your pump cycles back on.
Replace your pressure tank and your gauge so you can see what your water pressure is in the future. Also, a pump that constantly cycles on and off when youre running water will not last. This is the whole point behind having a pressure tank rather than just letting the pump send water to your faucets directly each time you open one. Hope this helps if you haven't already figured this all out.
Question: can the water pressure tank be adjusted to get water to my upstairs bathroom?
i have a water pressure issue with my upstairs bathroom. can the pressure tank be adjusted to fix this problem - Alysa 11/11/12
Reply: no, the problem is elsewhere
Question: short cycling pump, drained tank, air at zero, charged to 28, tank refilled, no more short cycling but bad water pressure remains
my pump was short cycling so I drained the pressure tank down. checked the air pressure and it was 0 . I charged it to 28 and refilled the tank with water. I solved the short cycling but now have very little pressure at the faucets. ? - Jason 11/23/12
Question: weak water pressure
I Justed replaced my pump and tank and the pressure in the house is still weak? - Brian 2/3/12
Brian at WATER PRESSURE DIAGNOSIS you can read how to diagnose and fix the trouble.
Question: reset Amtrol tank to 39 psi, pump shuts off at 41
Hi- just repressurised my amtrol water tank to 39 psi (water pump shut off at 41 psi). However, the schraeder valve at the top of the tank reads 39 psi but the pressure gauge at the bottom on the actual water line reads 31 psi. why the big discrepancy? and we're still having some problems with our water pressure on the second floor (new system- only three years old). - Paul 2/5/12
Paul this is not lab grade equipment; the gauges won't agree precisely but you can be darn sure that the pressure is the same at both points if measured at the same time. Sometimes a gauge gets sticky and stops reading accurately due to debris clogging.
Question: water pressure is very low right before the pump kicks in
Right before my well pump is about to kick in (40 psi) if I have two items running (say shower and laundry) the water pressure is very low to the fixture further away from the tank. Example, someone is taking a shower on the second floor and I start laundry on the first floor. The water pressure to the shower will drop to a trickle but the laundry is ok. This only happens right before the pump is about to kick in. It seems like the pump cannot recharge the tank quick enough. If I do this while the tank is at 60 psi, it is ok. This tank was replaced a few years ago with the same size that was originally there and with the exception of this one issue, it seems to be fine. - Maxx 3/7/2013
Reply: flow vs pressure clarification
almost everybody mixes up these points because the normal way we talk is about "water pressure" when what we really are talking about is water flow rate.
Water pressure is measured as a static number when no water is flowing - say 40 psi or 50 psi in the whole system - when the pump has cut off (or is about to cut on at some lowe rpressure).
Water flow rate measured in gallons per minute is what we experience as "water pressure" in the shower - I guess because at a faster flow rate we get pressed-on harder by the water as it strikes us.
When we have poor "pressure" (water flow rate) at a fixture the problem is usually because of clogged pipes. You can be sure this is true if the pump is capable of reaching say 40 or 50 psi of cut-off pressure. A second cause of poor water flow rate may be a very slow water delivery rate from the well - maybe because of a well flow rate restriction. I figure if it were really the pump itself then the pump wouldn't reach cutoff pressure even if the well had plenty of water in it. Other problems like a leak in well piping also foul up delivered water pressure.
Take a look at
Question: what is causing abnormally high air pressure in our water pressure tank?
Hope you can help me. I have a 16 y/o WELL-X-TROL WX 250 water well tank in my basement.
I just had a plumber come over and change out the pressure switch 40/60 The plumber drained the system , checked the air pressure in the tank which he found to be at 60psi. He then lowered it to about 34 psi (tank empty), changed the switch made sure everything was ok and when he left it was.
A day or two later my well started short cycling and the gauge would jump low then high to cut off at 60psi I kept an eye on it and called back the plumber to have him check it again. He rechecked and told my husband he raised the pressure inside the tank but on the ticket that was turned in, it was lowered.
It was okay for a day and started short cycling again. I then took out the water filter and found it to be clogged with sludge
I guess from the plumber draining the tank. I then cleaned it out and put it back in and tank was okay for a short while, the started short cycling again .
( UNIT SHORT CYCLES AS SOON AS I TURN WATER ON)
Today, 3/14/2013. 2 plumbers came back and told me my tank needs to be replaced but they drained it and found that the pressure in the tank was up at 60psi Again. What does this mean?. Now that they have left, the water ,pressure switch and tank seem to be okay. What do you think could be wrong ?
They want to put a new Well Mate tank in. What is the difference and first of all, AND DO I REALLY NEED ONE NOW THAT MY TANK SEEMS TO BE OKAY? THEY TOLD ME THAT THE GAUGE SHOULD READ AT 30 PSI ON AN EMPTY TANK. MINE WAS READING ZERO. IS THIS NORMAL???
My problem is that more air gets into the tank on it's own. I have drained tank, checked pressure and with each draining, the pressure at empty rises Is there a leak in the bladder which would allow air to come in after I have drained and reduced air pressure in the tank? Thank you.
- K.F. Kerhnonksen, NY 3/16/2013
Reply: difference beween high water pressure at a water tank and high air pressure in the tank
"air is entering the tank on its own" ? Not really. Air comes from somewhere, for a reason that needs to be addressed. But I agree that you're on to something and that a proper diagnosis and repair of the problem have not been done.
However there can be other sources of air entering the system that are not normal, including:
"Air pressure" in the water pressure tank at 60 psi is VERY HIGH, ABNORMAL, and should have raised a question (if it was really air pressure) of how it got there. Just bleeding out air doesn't fix anything if the cause is not found and fixed.
Now above I explain how we might get excess air entering the water supply system. Details about that problem are at AIR DISCHARGE at FAUCETS, FIXTURES.
But I suspect your system is not accurately described, and that our answer lies in your observation that the pump was short cycling.
If the well pump is short cycling the most common cause is a waterlogged pressure tank - that is a tank without enough air or with no air at all inside the tank. The pump turns on, there is no air to compress, the pump therefore almost immediately reaches cut-off pressure and cuts off. Water is flowing, pressure drops in moments, pump cuts back on.
So you are describing a waterlogged pressure tank. Details about diagnosis and repair are at WATER PUMP SHORT CYCLING.
In sum, I think it would be unusual (but not impossible) to have excessive air in the water system AND well pump short cycling. I imagine that might come up if you had an unusually signficant high volume and rate of air entering the system - say from an old air volume makeup device that should not be there, or a leak in well piping.
Keep us posted, what we learn will help others.
Question: abnormally high pressures in the water tank forced us to shut off the system - cause?
I replaced a 36 Gal Water tank in my home yesterday. Upon turning on the water and electricity to the pump, which was pre-pressurized at 25psi the pressure in the tank kept rising until I shut it off at around 70psi. Each time I turned the water and electricity on the pressure would continually rise until a point where I would shut the power to the pump off completely to avoid over pressurizing the tank. Do you have any idea on what could be the problem? Thanks! - B.E. 7/23/13
A competent onsite inspection by an expert usually finds additional clues that would permit a more accurate, complete, and authoritative answer than we can give by email alone. You will find additional depth and detail in articles at our website. That said I offer these comments:
Watch out: First, you were wise to SHUT OFF the pump - as overpressurizing the system is dangerous, risking a burst tank or piping. It is evident that the pump is working and water is entering the pressure tank, as its pressure climbs.
Second, I suspect that either a pressure is not connected, not working, or the pressure control switch may be mis-wired or defective. If you replaced some system parts but left an old pressure control switch it's possible that its sensor port is debris clogged. If so I'd replace the switch and its mounting or pressure sensing tube.
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