- POST a QUESTION or COMMENT about setting the air precharge pressure in internal-bladder type water pressure tanks
Ao smith aqua air v140 how to pressurize tank. Hi, we have a V100 and have had pressure problems lately in the house we just moved into last year (it's been fine until the other day). Tom stated that the tank pressure should be 2 psi below the pump cut-in. Our cut-in is about 38-40 psi but the tank pressure is 60 psi (the previous owner said.
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Water pressure tank air pressure adjustment:
How to check & then adjust or 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.
The page top photo shows the author testing the air pressure in a Well-X-Trol bladder type well tank.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
How to Select the Proper Air Pressure Charge for a Bladder-Type Well Tank
Please permit a safety warning before we get into the specifics of how to set the pressure in your water pressure tank.
Watch out: for very high water pressure readings in your system. If the water pressure is over 70 or 80 psi your system there can be a risk of burst water pipiong or a burst water pressure tank.
Such an event can both flood the building and can injure anyone nearby. Check the maximum water pressure you're using against the maximum water pressure rating for the pressure tank itself.
That's why your water supply system should have a WATER TANK PRESSURE RELIEF VALVE (separate article).
[Click to enlarge any image]
Factory air pressure settings in the water pressure bladder tank
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
- 18 psig for models WX-101 and WX-102
- 30 psig for models WX-103 - WX-203
- 38 psig for models WX-205 through WX-350.
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
Factory warnings about changing the bladder tank pressure setting
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.
- Do not adjust or add pressure if there has been a loss of air.
- Do not adjust the pre-charge pressure if there is visible exterior corrosion.
- Do not adjust the pre-charge pressure if there has been a reduction of the pump cycle time or the pre-charge pressure compared to its initial setting.
This is because reduction in pump cycle time can result from loss of tank air pressure which in turn can mean there may be internal corrosion and any repressurization or additional pressure could result in rupture or explosion.
How to Read Water Tank Pressure or any Pressure Gauge Accurately
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.
Watch out: Can you trust the installed water pressure gauge?
A separate round dial-type water pressure gauge is found on many water pump systems, at the pressure tank or near it, often on the pump itself. Sometimes these gauges lie: they get stuck or get debris clogged so they can give improper readings.
If that pressure gauge needle doesn't move when the water is being run or when the pump is coming on or off, it's not working properly.
Thoroughout this article series you'll see us using an independent pressure gauge to check water tank air pressure by pressing the gauge on the air valve that's usually located on the tank itself, near the tank top.
See WATER PRESSURE GAUGE ACCURACY for details.
Well Tank Air Pressure Setting at Time of Tank Installation
Set the well tank air pressure to 2 psi below the well pump control switch CUT-IN pressure.
We explain exactly how to do this just below.
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.
Watch out: If the pressure tank's air pre-charge pressure is set above the pump pressure control switch CUT-IN pressure then the pressure control switch will never turn the pump on.
Well Tank Air Pressure Adjustment Procedure
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:
- 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.
See WATER TANK DRAIN VALVE for procedures to drain any type of water tank or water pressure tank.
- Check the air pressure in the water tank by using an accurate air pressure gauge (such as a dial type or digital tire pressure gauge) to measure the air pressure at the schrader valve on the water tank.
The tank pressure should be within 10% of the original factory water tank pressure setting.
Our photo shows the water tank air inlet valve on the top of our Well-X-Trol well tank. We removed the cap and label for the photo.
Our photo at above right shows our digital air pressure gauge measuring the air pressure in the water tank.
The reading of 39 psi tells us that the dial pressure gauge that we illustrated
at WATER PRESSURE GAUGE ACCURACY (and located on this same water system) agrees with our pressure gauge within 1/2 psi.
Because water tank pressure controls normally use a pressure difference of 20 psi between the cut-in pressure and cut-off pressure at the water tank, a gauge error of one or two psi is not a concern. Thanks to Jeff Garmel for suggesting text clarification in this discussion of water pressure tank diagnosis. - Set the air pressure in the empty water tank to 2 psi below the well pump pressure switch cut-in pressure.
Bleed air pressure out of the water tank, or add air pressure into the water tank, until the tank pressure is at the desired set-pressure..
For example, if your well pump pressure control switch is set to 'cut in' (start pumping water from the well) at 30 psi, then set the pressure tank to (30 - 2) = 28 psi.
To add air to a pressure tank you can use any source of compressed air - a bicycle pump will do.
See WATER TANK AIR, HOW TO ADD for details.
For help finding the air valve used to add air to the water tank,
see WATER TANK AIR INLET VALVE - Replace the air cap on the tank air pressure valve and be sure that any warning labels that you took off during cap removal are back in place.
Leaky or Burst Water Tank Bladder Warnings When Adjusting Water Tank Air or Water Pressure
Watch out: these WATER TANK AIR PRESSURE ADJUSTMENT instructions are for an un-damaged water pressure tank that uses an internal bladder.
Reader Robert Ford pointed out by comment (17 Sept 2015) that if the internal bladder in the pressure tank has a leak or has burst you will probably have difficulty getting the water to drain out of the pressure tank. However his suggestion of using air pressure to force water out of the tank was not correct and could be dangerous.
Watch out: do not attempt to use high air pressure at the water tank's air adjustment valve to force water out of a water pressure tank that uses an internal bladder.
Doing so can rupture and destroy the bladder and worse, it can burst the water tank injuring or even killing a bystander.
If the water tank bladder has developed a leak or has burst water will have left the bladder and entered the air space in the tank making it difficult or even impossible to drain the tank completely.
That's because water that leaks into the tank's air chamber from a small hole in the tank bladder will not readily return to the bladder (water space) as you are draining the tank.
Further, if the water tank bladder has burst completely it can collapse, blocking all or most water from leaving the tank at all. If the internal bladder in a water tank is leaky or burst you'll need to replace either the bladder or the tank and bladder assembly. Adding air pressure will simply press the collapsed bladder more tightly against the water tank's drain opening.
See WATER TANK BLADDER REPLACEMENT.
If the water tank bladder is un-damaged, air pressure in the bladder will push water out of the tank completely leaving some air charge inside the bladder (unless you inadvertenly let air out of the bladder through the air valve).
In a bladder type water tank with proper pressure adjustment, when all water has left the tank you'll see air pressure at 2 psi below the pressure switch cut-in setting. Even if the tank air pressure is too low, you should still see some air pressure at the tank air valve when all water has left the tank.
See WATER TANK BLADDERS for an explanation of the difference between a bladderless and an internal-bladder water tank as well as for a description of what goes wrong with the internal bladder in water pressure and storage tanks.
Watch out: high pressures can burst the water tank bladder. Exposing the water pressure tank to excessive water pressures can also burst the water tank's internal bladder. Sometimes a water tank bladder sticks to itself, preventing water from entering the water tank and causing well pump short cycling.
We might un-stick the bladder by slightly and just temporarily over-pressurizing the tank by say 15 psi but we should never exceed or really even approach actual pressures close to the water tank's rated or safe operating pressure.
Typical maximum operating residential water pressures run between 20 psi and 70-80 psi. Higher pressures cause leaks and can burst the water tank or water piping.
How to Fine Tune the Pump Pressure Control Switch to the Water Tank
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 delay between the time that a water pressure tank becomes completely empty and the time that the pump turns on.
Usually this delay is brief, though some readers have reported that their pump simply did not turn on at all under these conditions.
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:
- Close off all plumbing fixtures that are using water in the building.
- Turn on the water pump and let the system run until the water pump cuts off.
- Open one or more plumbing fixtures to drain the water pressure tank; during this draining, watch and listen to the water tank and pump.
- If there is a momentary pause in the water flow from the time the well water pressure tank is emptied and the time that the water pump starts, adjust pump cut-in setting clockwise slightly to increase the pump cut-in (turn on) setting.
If your water pump is in your well rather than on or next to your water tank, you can't hear the pump run. But you can listen for the 'click' of the pump switch cutting in or out. For more photos and description of exactly which nut or screw to turn to adjust the well pump switch cut-in,
see WATER PUMP PRESSURE CONTROL ADJUSTMENT. - Close the plumbing fixtures and let the water pump continue to fill the water tank until the water pump cuts off.
- Check time it took to fill the water tank.
- Open the same plumbing fixtures again, follow the steps above, this time to see if pause in water delivery has been is eliminated. If not, continue adjusting pressure switch.
...
Continue reading at WATER TANK PRESSURE RELIEF VALVE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see WATER TANK AIR PRESSURE ADJUSTMENT FAQs - questions & answers posted originally at this page.
NO WATER PRESSURE if you have no water at all.
Or see these
Water Tank Air Pressure Adjustment Articles
WATER TANK DIAGNOSIS & REPAIR - home
WATER PUMP REPAIR GUIDE a specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost.
Suggested citation for this web page
WATER TANK AIR PRESSURE ADJUSTMENT at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.
INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS
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Technical Reviewers & References
- Thanks to Jeremy Houser who suggested that we needed to clarify the difference between bladder type and non-bladder type water tanks when discussing air charging and diagnosis of water tank repairs.
- Thanks to Jeff Garmel for discussing clarifications on water pressure tank testing and diagnosis, 8/24/2009.
- Amtrol Extrol™ pressure control tanks, which they call well tanks, are described at the company's website at www.amtrol.com/extrol.htm and installation and operating instructions for these well tanks can be found at www.amtrol.com/pdf/9015A290revcWXT.pdf
- Well-X-Trol: Amtrol Extrol™ pressure control tanks used on hydronic heating and other systems such as models 35LBC, 50 LBC, 85 LBC, and 100LBC to 600 LBC also use a bottom bladder containing air - see amtrol.com/pdf/LBCSeriesEXTROL9017-095.pdf for details.
- Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 [email protected]
- John Cranor [Website: /www.house-whisperer.com ] is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-873-8534 or by Email: [email protected]
- Wessels Company bladder replacement store was found at westank.com/bladder-tank-store.php on 5/22/2009. Wes sell refers to 'shock and surge tanks' as ASME replaceable bladder type and pre-charged hydropneumatic tanks used for commercial, industrial, and well water systems.
- Thanks to reader Howard Jackson for technical editing of proper pressure settings for the Well X Trol WX-103 - WX-203 tank bladder pressures - June 2010
- [1] Well-Rite water tanks. Well-Rite water tanks are produced by Flexcon Industries, 300 Pond StreetRandolph, MA 02368Tel: 781.986.2424, based on manufacturer data provided on the shipping carton for a 44 Gallon / 170 Liter internal bladder water pressure tank during installation in Northern Minnesota, September 2011.
- Rasmussen Well Drilling, Inc., 1793 Hwy 61, Two Harbors MN. Jeremy Rasmussen provides third generation well drilling and plumbing services on the North Shore of Lake Superior. Photos by DJF. Tel 218-834-3387. Email: [email protected]
Quoting: We serve the north Shore – Lake, Cook, St. Louis, Carlton and Pine counties, including Duluth, Grand Marais, Clouqet, Carlton, Finland, Isabella, Silver Bay, Grand Portage, Saginaw, and everywhere in Northeastern Minnesota. - Crystal Clear Supply provides portable ceramic water filter purifiers and portable reverse osmosis water treatment equipment - see http://www.crystalclearsupply.com/category_s/7.htm
- Handbook of Disinfectants and Antiseptics, Joseph M. Ascenzi (Editor), CRC, 1995, ISBN-10: 0824795245 ISBN-13: 978-0824795245 'The evaluation of chemical germicides predates the golden age of microbiology...' -
This well-focused, up-to-date reference details the current medical uses of antiseptics and disinfectants -- particularly in the control of hospital-acquired infections -- presenting methods for evaluating products to obtain regulatory approval and examining chemical, physical, and microbiological properties as well as the toxicology of the most widely used commercial chemicals. - Potable Aqua® emergency drinking water germicidal tablets are produced by the Wisconsin Pharmacal Co., Jackson WI 53037. 800-558-6614 pharmacalway.com
- Principles and Practice of Disinfection, Preservation and Sterilization (Hardcover)
by A. D. Russell (Editor), W. B. Hugo (Editor), G. A. J. Ayliffe (Editor), Blackwell Science, 2004. ISBN-10: 1405101997, ISBN-13: 978-1405101998.
'This superb book is the best of its kind available and one that will undoubtedly be useful, if not essential, to workers in a variety of industries. Thirty-one distinguished specialists deal comprehensively with the subject matter indicated by the title ... The book is produced with care, is very readable with useful selected references at the end of each chapter and an excellent index. It is an essential source book for everyone interested in this field. For pharmacy undergraduates, it will complement the excellent text on pharmaceutical microbiology by two of the present editors.'
The Pharmaceutical Journal: 'This is an excellent book. It deals comprehensively and authoritatively with its subject with contributions from 31 distinguished specialists. There is a great deal to interest all those involved in hospital infection ... This book is exceptionally well laid out. There are well chosen references for each chapter and an excellent index. It is highly recommended.' The Journal of Hospital Infection.: 'The editors and authors must be congratulated for this excellent treatise on nonantibiotic antimicrobial measures in hospitals and industry ... The publication is highly recommended to hospital and research personnel, especially to clinical microbiologists, infection-control and environmental-safety specialists, pharmacists, and dieticians.'
New England Journal of Medicine: City Hospital, Birmingham, UK. Covers the many methods of the elimination or prevention of microbial growth. Provides an historical overview, descriptions of the types of antimicrobial agents, factors affecting efficacy, evaluation methods, and types of resistance. Features sterilization methods, and more. Previous edition: c1999. DNLM: Sterilization--methods. - U.S. Army Field Manual 21-10, Field Hygiene and Sanitation, 1988, web search 07/02/2010, original source: http://www.enlisted.info/field-manuals/fm-21-10-field-hygiene-and-sanitation.shtml
The purpose of this manual is to assist individual soldiers, unit commanders, leaders and field sanitation teams in preventing disease and environmental injuries. The manual provides information on preventive medicine measures (PMM) to the individual soldier as well as essential information for the unit commander, unit leaders, and the unit field sanitation team on applying unit level PMM. - When Technology Fails, Matthew Stein, Chelsea Green Publisher, 2008,493 pages. ISBN-10: 1933392452 ISBN-13: 978-1933392455, '... how to find and sterilize water in the face of utility failure, as well as practical information for dealing with water-quality issues even when the public tap water is still flowing'. Mr. Stein's website is www.whentechfails.com/
- ...
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