Water tank air valve test (C) Daniel Friedman S PriorWater Pressure Tank Bladder Diagnosis FAQs #2
Questions & Answers on Internal-bladder Water Tanks

  • WATER TANK BLADDER DIAGNOSTIC FAQs-2 - CONTENTS: questions & answers about diagnosing & fixing problems with the internal bladder used in many water pressure tanks: burst tank bladders, tank bladders collapsed & stuck to themselves, how an internal bladder is replaced in some water tanks.
  • POST a QUESTION or READ FAQs about diagnosing and repairing problems with water tanks that use an internal bladder

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Internal bladder type water pressure tank diagnostic questions & answers:

These questions & answers help diagnos & fix problems traced to the internal bladder used in water pressure tanks.

This article series describes the diagnosis and repair of internal bladder type water pressure tanks: how they work, what goes wrong, how to fix it.

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Water Pressure Tank Diagnostic Questions & Answers, Series 2

Water tank construction details showing bladder (C) Daniel FriedmanThese questions and answers about diagnosing problems in water pressure tanks were posted originally at WATER TANK BLADDER PRESSURE ADJUSTMENT - topic home. Be sure to see that article.


At Continue reading we provide an INDEX to RELATED ARTICLES that includes a live link to - WATER PRESSURE LOSS DIAGNOSIS & REPAIR.

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

No Alisa,

The water tank smooths the delivery water pressure but does not increase nor decrease it.

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



Take a look at the cut-off pressure: typically it's set to 40 or 50 psi. If your cutoff pressure is in that range and the "pressure" (really flow rate) at your faucets is poor, it sounds like a valve, faucet strainer, water filter, or pipe clog problem.

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 for WELLS 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. Check for a pressure control switch not responding to a fall in water pressure - e.g. due to debris clogging at the switch.

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 .


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 ?



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.

If a water tank bladder has burst and thus leaks, nothing keeps water and air separated.

Air in the tank might enter the water supply, but especially on an internal-bladder type water tank where there is no air volume control used to keep putting air into the system, there is not NORMALLY any source of additional air entering the system. The tank becomes waterlogged and the pump short cycles.

However there can be other sources of air entering the system that are not normal, including:

  1. an old snifter valve in the well or on the well piping that should have been removed when the new bladder type tank was installed
  2. well water running low, pump picking up air
  3. leak in well piping lets water out and air in depending on when in pump cycle

"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.

Question: pressure in the empty water pressure tank keeps rising on its own

(Jan 21, 2014) Anonymous said:

I have a 30 year old wx202 and I have also seen my empty tank pressure rising. I am surprised that so many professionals seem unable to explain this. As I did not have air coming out of the faucets,the problem could not be excess air. I could feel that the tank still had water in it after the drain valve stopped flowing.

Cracks in the diaphragm allowing water to pass above the diaphragm fully explain the problem.

On draining, the cracks close up like a check valve preventing escape of the trapped water. In order to reduce stress on the pump during the 2-3 weeks until a new well-extrol #WX255 81 gallon tank arrives, I drilled through the welded fitting on top and tapped it for a 1/8 in pipe plug. Lacking a 1/4 in bit long enough, I hammered a 3 ft long 3/16 rod through the hole.

I could feel it going through the diaphragm. I repeated this 6 times at different angles. Water flowed out of the tank for 20 min and the tank finally felt empty.

After precharging to 34 psi the 37/57 system worked properly for the first time in months except for multiple tiny leaks caused by this trapped water rusting its way through the steel near the diaphragm stop plate about 6 inches from the top of the tank. "JB Weld" has worked well on the worst leaks and it cures in a couple of hours with a heat lamp, allowing system restoration before others in the house wake up in the morning.

I plan to reduce the precharge pressure of the new tank to provide "supplemental drawdown". This will provide water during an unexpected loss of power or after the generator is shut down during a power failure. I will reduce the differential and increase the setting to 45/55 if the switch can handle it. The manufacture's sales rep of the tank agrees with this use as long as I stay in the 30/60 window for a 30 psi precharg with this tank. He did warn of reduced tank life if I stretch the diaphragm against the stop plate very often. All of the 22 in dia tanks have the same diaphragm and store the same 34 gallons of water, but have different air above

Question: water pressure lost when water tank froze

(Jan 29, 2014) Stephen Linturn said:

we have a 2 year old bladder tank in the garage, about 250 feet from the house, during below zero temps we lost water pressure. Heated up the tank and it came back on, now the pressure is 90 on the tank, it has stayed there for hours and not moved. We are not sure if the pressure gauge is working. How can we tell? I released pressure in the valve.

It is not making any noise of any sort. The pump is under ground, our well is about 300 feet down. Is this anything I should be concerned about? Can I sleep well? Thanks Stephen



90 PSI is too high - and I'd worry about blowing the tank - which could injure a bystander.

But the pressure in the tank may or may not really be 90.

The gauge may be jammed.

Or the tank may be freezing and pushing up pressure at the gauge.

I would turn off the pump,
Open the tank drain

and if no water comes out, the tank is frozen or the bladder is jammed.

I would not work alone, and I'd be careful to be protected should the tank burst.

Chances are it's the gauge, but geez, writing a post online for an unseen system - it's best to be very careful.


Was the pump off when you saw that 90 psi? If not I'd immediately shut the pump off.

Question: no water seems to enter the bladder pressure tank

(Feb 7, 2014) chris hampton said:

my nearly new bladder pressure tank has no water in it.what could be wrong?also when continously running pump is turned off,water runs from house piping back into well.



No water entering an internal bladder type pressure tank, assuming the pump and tank are working, usually means that the bladder has collapsed and stuck to itself, blocking the water input

But when the pump runs continuously and when water runs back into the well when the pump is turned off
that sounds like a bad foot valve or bad check valve combined with loss of prime in the pump. If your pump is an above ground pump that's more likely the problem.


AUTHOR:D Adam (no email)

COMMENT:Hi guys,
I have a 18Lt pressuretank and SquareD switch. On installatin it was all set to factory -switch 30psi -50psi and tank at 28psi. Not being happy with the low pressure at 30 I decided to turn the large nut clockwise until I got high pressure at 60.

Since doing this i notice the draw down has been reduced and causing the pump to cycle even with a half toilet flush... It used to last atleast 2 flushes before.
My question is, would this be because I didnt add pressure to the tank bladder? Should I do as above and add pressure to 38psi (cut in 40) and will this fix the problem?
Cheers from Australia!
D Adam


Adam, in the More Reading links above I've added a link to our article series titled


there you will see the explanation of the large and small adjustment nuts in that control, and you'll see additional detailed articles about adjusting the two nuts individually and together; I suspect your switch needs corrective adjustments.

Reader follow-up:

I think you may have misunderstood my questions. Setting the adjustment nuts is fine as I've read nearly all the articles including the one you mentioned :)
What I'm trying to figure out is ...
1. Now I have my switch set to 40-60psi do I need to add air to my pressure tank to make it 38psi?
2. And is this why the draw down is less (because I increased switch cut in to 40 but didn't adjust the bladder/tank pressure?)


Yes D. Adam; you want the starting pressure in the bladder tank to be about 2 psi below the cut-in pressure. Details are in an article titled WATER TANK BLADDER PRESSURE ADJUSTMENT - found by searching InspectApedia

When you change from 30/50 to 40/60 you still have the same 20 psi difference between cut in and cut out; Shifting to a 10 psi higher operating range but keeping the same delta or variable (20 psi) means that the higher pressure will push water out of the tank faster than before, reducing the *perceived* drawdown even more than the actual measured volume of drawdown.

In a table in the article above using a similar tank size, the pressure range change you make drops the drawdown volume from 6.2 to 5.4 g

But yes do set the tank air pressure as discussed in the article I cited, or generally at 2 psi below the cut-in pressure. That will give the maximum available volume and thus drawdown.

Reader follow-up:

Thanks Dan!
That basically answered my question. I'll adjust the pre charge over the weekend and see how it goes...hopefully no dramas (can't see a relief valve anywhere-only the fill in schrader, fingers crossed it don't blow up)
Cheers, D. Adam


Great D. Sorry to be obtuse but often when communicating just by text it can be a challenge to get a clear idea of what's going on from the questioner's side.

As long as you stay well below the tank rated burst pressure you're safe. Certainly an air loading causing pre-pressurizing of a water tank at a pressure that is below the tank's operating range and below the cut-out pressure should be safe.

With smaller vessels, like a bicycle tire, it is easier to blow the thing up when hooking to a high pressure air source. But I did learn of a case in which a plumber was working leaning over a pressure tank connected to a submersible well pump - the pump was running ( and is capable of high pressure) - and blew the tank. He was working alone, was cut by the damaged tank, and died. Rare, but possible.

The common place to add a relief valve is on the tank tee at the bottom of the pressure tank.

Question: replace tank with pinhole leak?

(Feb 19, 2014) Anonymous said:

The elbow pipe to a “Challenger series Diaphragm well tank” has a pin hole leak so I need to replace it. Do I need to make pressure adjustments either prior to or after replacing the pipe?

Thanks in advance for any advice you may give.


You can patch a pinhole leak using a special short lag screw and rubber or neoprene washer - assuming this is a bladderless pressure tank; but beware that as tanks corrode from inside out the tank may be more rusted and closer to end of life than you think.

Question: pump kicks on every 3-4 minutes when water isn't running

(Feb 23, 2014) Scott said:

Hi, I have had a problem with my pump kicking on about every 3 to 4 minutes when the water isn't running. I checked all my pipes in my house and in the crawl space and can't find any leaks or anything. I went down in the crawl space and checked the water pressure tank and there is no visible leaks and didn't hear any air leaking either. I don't know whether or not this tank has a bladder or not and not sure as what to do next. Any help would be outstanding. Thanks


Scott, in the page top section titled "Click to Show Hide Related Topics"

find and click on


for the diagnosis of the problem you describe.

Question: what is the effect of increasing the air pre-charge pressure in the water pressure tank?

(Apr 8, 2014) reese said:

basically, what happens if we increase the precharge pressure of water tank? will the water pressure increase also? just a newbie here. thanks


Reese, you are asking an important question as I know it's easy to be confused about this pressure and tank business.

Overall the pressure of water delivered at a plumbing fixture will never be higher than the pressure that can be produced by the water pump itself. The system pressure will vary while you are running water, between the pump pressure control switch cut-in and cut-out pressures, say 20-40 or 30-50 psi.

The pressure tank, containing air and water, is acting as a sort of spring to smooth the flow of delivery of water. If we didn't have that spring, then when the pump turned on it would quickly reach the cut-off pressure - in seconds - and cut off, then pressure would fall to the cut-in pressure - in seconds - and the pump would turn on. That rapid short-cycling of the pump will kill it as well as drive you crazy seeing water squirting at the faucet.

The pressure in the water pressure tank should be set to about 2 psi below the "cut-in" pressure of the water pump.

If you made the big mistake of setting the pre-charge pressure in the water tank to ABOVE the cut-in pressure of the switch, the effects is you are reducing the available water volume in the tank, tending towards a short-cycling system. Why? because at the higher pre-charge pressure the volume of the tank's air charge is increased when water has been pushed out of the tank.

If we take this to an extreme and fill the water pressure tank with air, in a bladderless tank no water will enter the tank and in fact air will be pushed out and into the building piping. In an internal bladder type tank, filling the tank with air, if it doesn't burst the bladder, eliminates any available volume in the tank for water - the pump will still turn on and off based on building water piping pressure and it will short cycle like mad.

If this is still unclear, ask me again.

Reader follow-up:

(Apr 9, 2014) reese said:

thank you for your important reply. in this case, how will i increase the water pressure to satisfy required pressure to supply 3 fixtures at the same time (shower, water closet, lavatory)in case we used them at the same time considering that this 3 fixtures are also existing in other rooms?

Our local water service is a bit weak. we have decided to buy a water storage tank with a capacity of 2000 liters, a 2hp jet pump with complete attachments (gauge, pressure switch, check valve), and a bladder type pressure tank (tank volume 33gal).

Pipe size is 1 inch in diameter from storage tank to pump to pressure tank. but after the pressure tank, the pipe size is only half inch in diameter all the way up to our rooms. I

compared the pressure of our local water utility and pressure from the pressure tank (without connecting yet to the building pipes), based on the squirt, water from the pressure tank squirts farther than the local water but when connected to the building they produce the same result (same water pressure output)its like that the pressure tank is useless.

Hope you can help me solve my problem. again thank you very much.


Reese, Whew! reading that dense paragraph. Have mercy.

Typically people improve water pressure by one or a combination of measures. First we need to accurately diagnose the cause of poor water pressure - so that we can then choose the right repair.
Therefore, start at
WATER PRESSURE PROBLEM DIAGNOSIS TABLE in the "More Reading" links above.

Question: when the pressure tank is installed and filled for the first time where does the already in the tank air go?

(May 5, 2014) Dan said:

When installing a replacement tank, when the empty tank is filled for the first time where does the air in the area being filled with water go? Does it compress or is there some kind of valve that allows the air to escape and be replaced with water?


Dan thanks for the question.

The air doesn't go anywhere - that is, it's not supposed to escape or go away. Rather, it is being compressed. It's that compressed air that pushes water back out of the tank when you open a faucet, and it's that "spring" like feature of squashed air that pushes back that keeps your well pump from otherwise cycling on and off too rapidly.

Question: Can I keep using a water pressuretank after the bladder is busted?

(May 22, 2014) donbates38 said:

can i still use my tank if the bladder is not working by just puting air in tank


You'd think so but that won't work well nor long. The tank is not designed to have water outside its bladder - expect corrosion & leaks; and often the bladder fragments prevent water from properly entering or leaving the tank.

Question: New pressure tank, trouble getting pump to turn off

(June 15, 2014) dave ross said:

put a new pressure tank in--simer pre-set at 38#-----put a new pressure switch on pump--pre-set at 30-50#---I dropped the pressure in the tank (very carefully measured) to 28#----now having devil of time with pump even cutting in/off---have not made adjustment to switch yet-- must start pump manually --- question-- read that on this site to let pump run until it shuts off observing pressure at which this happens-- will this burst the bladder with 28# still in tank?????
dave ross

(June 18, 2014) Pete said:

I have a fairly new Well - X - Troll system that pulls water from the lake to feed my irrigation system.The pressure switch is a 20- 40 PSI switch. The pressure gets to 40 PSI fine and stops. However, almost as quickly as the irrigation system starts, the pump kicks in. It goes down to about 30 lbs. pressure and stays there. Consequently the pump never stops and then eventually kicks the 15 amp breaker off. It's a 1 horse motor. Any idea on the problem? Need a bigger motor - new pressure switch so it drops to 20 lbs before it kicks in - create more zones in the irrigation system so it doesn't draw so much water at any one time - 20 amp breaker????

(June 21, 2014) Rich said:

My tank keeps kicking on and off. In addition to this the it is making a loud thumping sound and water is squirting out of a ball valve... The pressure reading is sitting at a constant 40psi (supposed to be 60/40). And i have a Amtrol Champion series tank. Any ideas?



A good diagnostic is at

Pete I suspect two conditions:

The water flow rate of the irrigation system exceeds the pump capacity ( or,a pickup screen is partly clogged), so the pump runs continuously at its maximum output which never gets ahead of the use rate, so it never shuts off until you turn off the water.

And there may be a problem with the pump itself, or low voltage, or voltage drop along a very long wire, that can also overheat the motor.

You could try running irrigation at a slower flow rate or in fewer zones at any time.

Rich: You want to see WATER PUMP SHORT CYCLING

Question: water system works ok only at low demand - lose pressure at high demand

(Feb 22, 2013) Anonymous said:

tank precharge pressure is 1.94bar but pump cutin pressure is 3bar shall is increase precharge pressure

(July 13, 2014) Anonymous said:

I have a submersed pump w/ a 30 gallon pressure tank, and a 40/60 pressure switch.39 psi in tank. At low demand, the system works normally. at high demand, the pressure continues to fall past the 40 psi cut in pressure and shuts off the pump, To restart I have to activate the bypass lever on the pressure switch and hold until proper pressure is established.


It's possible that the high water usage rate exceeds the well flow rate. In that case the switch is shutting off the pump to protect it from damage, working as it should.

Forcing the pump to run may damage it.

Try waiting an hour or more before turning on the pump after it has shut down. That gives the well time to recover. If the system runs normally at that point we have diagnosed the trouble.

Depending on the well's recovery rate it could take longer still for this procedure to work.

Question: trouble getting tank bladder pressure settings

(Aug 16, 2014) John said:

Recently replaced a 40 year old 20 gal pressure tank & its piping with a new Water Worker HT20B, 20 gal tank and new SS piping. Also replaced the old Square D pressure switch with new Square D 30-50 unit.

The first day, with the wrong pressure in the bladder (38psi) and some water hammer in the system, I bled the bladder down to 28 psi and it seemed to run OK for a time.

Then, strange things began to happen; the pressure switch would cut in at the normal 30 psi, however it seemed the downhole well pump wouldn't respond for a few seconds, then when it kicked in, the system pressure was already below the precharge of the bladder, so there was water hammer again.

Adjusted the bladder charge down to 25 psi, and again it seemed to run OK, but then the same phenomenon occurred. The pump didn't seem to start running for some time delay after the pressure switch "cut in". I did measure the voltage on the load side of the pressure switch, and it was OK, so I know that voltage was getting to the pump, however I didn't have the necessary instruments with me to see if it was actually pulling current immediately, or only after this "time delay".

The pump itself is also 40+ years old, however since this is a seasonal use cabin in MT, it actually hasn't seen much service. Nevertheless, does it sound as though the pump itself is failing?


John you were on the right track but when "...[you] bled the bladder down to 28 psi and it seemed to run OK for a time. "
That 28 PSI should be the air pre-charge when the tank is empty of water.

(Aug 18, 2014) Anonymous said:

Thanks Daniel, I should have clarified that statement - I did bleed the bladder down to 28 psi after draining the system and tank, and opening the system to atmospheric pressure. Guess I'm looking for some guidance on whether there could be a problem with the new surface equipment I installed (pressure tank, tank tee, check valve, pressure relief valve, pressure switch), or if it's downhole.

If it's downhole, I'm going to go ahead replace the entire assembly (pump, piping, wiring, etc.) as it's all 40 years old, and I don't want to have to pull it again in the future.



Do you think that the delay in apparent response of the in-well submersible pump that occurs after the pressure switch has called for water could be

- a problem in a separate pump relay operated by the pressure switch? Some higher HP submersibles use a heavy duty relay control that is itself switched by the pressure switch.

- a leak in well piping that is draining back into the well? (Look for air discharge at fixtures)

About the old pump motor - that's a fair question to ask, but I'm not sure where to go with it. Look at not voltage but current draw to see if the pump is behaving as if binding or sticking (high current) or pumping air (low current). It'd help if you knew the pump specs which perhaps are not known.


(Aug 18, 2014) Vahid said:

I have a booster pump station including 4 pumps that they cut-in via pressure and flow rate. The pumps have VSD. The cutin level is 45m head and the pumps have to maintain the pressure at 50m head. I have got two 80L Pressure Vessels (29l drawdown volume of each)on the discharge line. I want to know at what pressure should I charge the vessel (43 m or 48 or ?) ? another control on this station is that the PLC looks both at Pressure and minimum Flowrate


Vahid, In general the air pre-charge pressure in the pressure tank is set 2 psi below the cut-in pressure set at the pump controller. But your system merits comment by an engineer who has expertise in its special function and design.


Carl said:

Hi. Having just drained my system and installed a new pressure regulator and bladder on my pump and pressure tank, the pump is taking more than half an hour to get to the 50 PSI cutoff. It may indeed have taken a while to refill the bladder, but I was getting concerned and so unplugged the pump. The new regulator is a 30/50 cutoff, while the old one was 40/60. If I had, say, 38 PSI in the tank, what effect would this have with the new 30 PSI cut-on? From your previous answers, I'm guessing it would just be lower water volume and cause more frequent cycling. I can't see why it should be taking so long to charge.



Carl, look for

a damaged or clogged foot valve or strainer, a damaged pump impeller, low voltage, or leaks in the well piping


Question: water pump and tank to support water source heat pumps

29 May 2015 Jack said:

I use my water pump and water holding tank exclusively to support my water source heat pumps. The plumbing of the water tank is standard with a pressure switch controlling the power to the pump but the water discharges to a pond in my backyard after going through the heat pumps to pull the heat/cold from those units. I also have a relay (tied to the thermostats of the water source heat pumps) wired in series to the water pump pressure switch to control power to the water pump so the it won't activate unless the heat pumps are in use.

The system has been in use for about 34 years and worked fine until recently. My problem now is that at times (but not all the time) there is a loud hissing sound like air mixing with water near where the pipe from the water tank ties into the water line heading to the heat pumps. Even with the hissing sound, the water appears to run properly through the heat pumps and discharge at a normal flow rate. When I begin to close a water valve (located after the water holding tank) that restricts flow to the heat pumps, the hissing sound is reduced.

The pressure switch gauge normally reads about 20 psi when the water pump is running but at times reaches a level of 80 - 100 psi when the hissing sound starts. I suspect the gauge may be giving a false reading since the discharge end of the water pipe is open and water appears to flow from the discharge end at a high rate. The water holding tank may not be necessary in my usage, but I had hoped the water holding tank and pressure switch would serve to turn the water pump off if the water pressure reached an abnormally high level. Could the loud hissing sound somehow be related to a problem with my holding tank or pressure switch?


Pressures in a water supply system much over 70 psi are dangerous, can burst a tank or pipe, injur someone, or flood the building. I'd look for a pressure switch or switch sensor problem, and I'd be sure there was a properly installed pressure relief valve on the system.

Question: water tank air pressure reading when the tank is empty

(June 14, 2015) Ronnie said:
Should air bladder read pressure with tank empty.



With no water in the pressure tank the internal bladder type water tank is typically set to an air pressure of 2 psi below the pressure control switch cut-in pressure. So if your pressure control is a 30/50 model your tank precharge is 28 psi.

Question: pressure slowly increases, then rockets to a high number then crashes

(July 4, 2015) Mike V said:
My pressure tank is set at 40 psi the pump goes on at 42 psi and goes off at 64 psi. I check this several times running the water. Interesting thing is as the tank charges it's slow from 40 to 50 then rockets up from 50 to 65 then crashes to 50ish and sinks slowly back down to 40. All while the water is running. If I shut the water quickly at 65 it stays at 65. What is going on?


Interesting and strange, I agree. It sounds as if there is a sticky internal bladder in the pressure tank (if that's the type of tank you've got); also the pump output itself may be affected by the pressure level in the system and system pressures in turn by the usage flow rate. Those are some thoughts. Bottom line, I am confused by the data and don't have a sure answer.

Check also for a sticking pressure gauge. Start by hooking up an independent water pressure gauge to monitor pressure.

Question: signs of a bad water pressure tank bladder

(May 4, 2015) B. Murdock said:
When power is on, the well comes on and of, on and off, can hear water start to come into the system.
Can the pressure tank or bladder inside be bad?



Question: how to install a bladder type water tank: need a tank tee? Working pressures?

(June 9, 2015) said:
lam trying to install the above bladder tank its specks are
vessel volume 98.4 liters/26 gallons max working pressure 8.6 bar/125psi l have no manual and never installed this type of tank l see there is only one outlet from the tank which seems to me l add a tee from the water inlet but how does this work if the water cannot go in and come out at the same time through the same whole there must be an obvouse reason please help me kind regards alan martin



Indeed most water pressure tanks using an internal bladder have a single piping connection to which a tank tee is installed to accomodate water from the pump as well as a pressure relief valve and pressure gauge as well as a connection to piping feeding the building.

When the pump is running water is pushed simultaneously into the pressure tank and into the building through the two openings provided by the tee (one into the tank, one into the building). When the pump is not running and water is turned on in the building air pressure in the tank pushes water out of the tee and into the building - until pressure falls low enough to turn on the pump.

For safety you should find the installation instructions from the tank manufacturer and follow them.

Watch out: no residential water tank should actually be operating at the maximum working pressures you cite; typically residential pressures range between 20 psi and 70 psi or perhaps 80 maximum. Higher pressures are unsafe and also cause leaks.

Question: water pressure stops briefly then returns

(July 6, 2015) Colin said:
My water stops briefly when we are having a shower. My pressure switch drops from 30 to 10 then climbs up again.

(July 16, 2015) Bill said:
Same problem as Colin, July 6 2015, solution?


Colin and Bill: look for a water pressure control switch that is sticking due to burned points, debris inside the switch assembly (mud dauber wasps), or debris clogging of the pressure switch sensor port. Replace the switch.

Question: OK to install a bladder type water tank on its side?

(July 21, 2015) Cathy said:
Can a bladder tank be installed on its side instead of upright? Will it still work properly that way?


Probably not. Most manufacturers expect the tank to be upright. You may stress and tear the bladder.

I refer to water supply system pressure tanks.

The smaller internal bladder tanks used as expansion tanks on heating systems (not on water supply systems) can often be installed horizontally or even upside down.

Question: How to get the water out of a water tank with a damaged bladder.

16 Sept 2015 Robert Ford said:

The statement:

Remove all water from the water tank. This means turn off the water pump, open a nearby plumbing fixture, run water until the water stops entirely - your water tank should be empty or close to empty.

Could be incorrect; If the bladder has failed and the tank becomes waterlogged (incorrect ration of air vs. water) you would only get a very small portion of the water to empty. If this was the case, one would need to force the rest of the water out via an air compressor.

Ideally, you would draw water until the pump starts. Ensure that all faucets are turned off.Once it pumps up to pressure, cut the electric to the pump and close the gate valve between the pump and tank. Open a faucet to begin draining the tank.

Attach an air line from compressor to the air snifter valve.

The compressor will then empty the contents of the tank. Once the last of the water empties it will begin to sputter (mixture of air and water). At this point, close the faucet and continue to add air until the proper pre-charge for the tank is met. This can be verified by a working pressure gauge or separate air gauge.

Next, turn on the pump and open the valve going to the tank. If the well is old, this should be opened slowly at first. If the pump begins cycling on and off very quickly continue to open the valve further until the pump stays running continuously. This will help ensure the pump does not lose it's prime

. If the system has a shut off valve between the tank and household lines it would be best to close this until the pump has full cycled and shut off.


You are right, Robert; in a typical bladder-type water pressure tank (not all tanks use an internal bladder) if the bladder has failed water may pass out of the bladder into the area in the tank intended for air. In that case draining the tank may be incomplete as the collapsing bladder can also block the tank drain.

But your repair procedure is not correct for that situation and it's unsafe.

Watch out: However for that situation the repair you suggest would be improper and possibly dangerous. If the bladder has collapsed onto the tank drain no safe amount of air pressure will empty the water in the tank and at higher pressures the tank can burst, injuring or even killing someone (this happened to a plumber in New Paltz NY).

If the internal bladder in a water pressure tank has burst the proper repair is to replace the bladder completely or to replace the entire water tank assembly.

Your comment is in an article on adjusting the air pressure in a working water pressure tank system.

To simply drain a water tank see WATER TANK DRAIN VALVE at

Or see WATER TANK AIR INLET VALVE - opening this valve can help in draining a water tank -

For a complete set of procedures for water tank diagnosis and repair please see WATER TANK: USES, TROUBLESHOOTING - home at

At More Reading above in this article you'll find links to other water tank maintenance and repair articles, and our complete list of pump, pump control and water tank diagnosis and repair articles is also given above at INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS

I appreciate your comments and will review our articles to be sure that these points are clear.

Regarding your reference to an "air snifter valve" - air snifter valves are NOT USED on water pressure tanks that use an internal bladder. In fact if such a valve is left installed on a system that was converted from a bladderless to an internal-bladder water pressure tank the system will not operate properly.

On a conversion to an internal bladder tank the snifter valve (normally present on well piping just ahead of the tank) and the corresponding snifter valve air inlet (located on well piping in the well) must be removed.


However there is an air pressure adjustment valve (looks like a tire valve) atop water tanks that use an internal bladder. See WATER TANK AIR INLET VALVE at for details.


With water pressure tanks that use an internal bladder you should never see air discharge at the building's faucets. If you do there is a problem with the system that needs repair such as

- an air leak into the well piping

- an air leak at the pump itself

- a snifter valve and drainback valve that should have been removed when a bladder type tank replaced a bladderless water tank

- a ruptured water tank internal bladder


Continue reading at WATER TANK BLADDER PRESSURE ADJUSTMENT or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WATER TANK BLADDER FAQs - questions about water tank bladders: use, function, installation, repair

Or see WATER TANK BLADDER DIAGNOSTIC FAQs-3 - Set 3 of Q&A on water pressure tank bladder diagnosis & repair


Or see these

Bladder Type Water Tank Articles

Suggested citation for this web page

WATER TANK BLADDER DIAGNOSTIC FAQs-2 at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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