Fiberglass or plastic water pressure tanks:
This article describes how to identify, diagnose and repair of WellMate™ water tanks, including both internal air bladder-type tanks (WellMate™ captive air water tanks) and bladderless traditional or hydro pneumatic type water pressure tanks such as the WellMate™ Traditional Air/Water tank: how they work, what goes wrong, how to fix it.
Captive air tanks that incorporate an internal, replaceable air cell or bladder, and bladderless hydro pneumatic water tanks (shown at the top of This article ), also called traditional residential water tanks that incorporate no internal bladder but use a tank top mounted air volume control.
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Reader Nancy Martin asked how to diagnose well pump short cycling and a possible water tank or bladder problem for the WellMate bladder-type water tank which uses the tank bladder to retain the air charge in a water pressure tank.
WellMate™ describes two types of water pressure tanks used in residential and light commercial applications:
Our WellMate links near the bottom of This article can direct you to photographs that help identify which type of water tank is installed at your property.
These are different tank designs so first we need to know which type you have - take a look at the photos at the two WellMate links.
Type 1 or captive air water pressure tanks sold by WellMate and some other manufacturers are constructed of fiberglass and use an internal bladder to hold the air charge.
If the air bladder has ruptured, the water tank will begin to act like an old-fashioned steel water tank - air absorbs into the water until there is not much air charge, the tank becomes water logged, and the well pump will short cycle on and off. Our description of conventional steel water tanks adds details. If the air bladder has failed, the tank will act much like a type 2 hydro pneumatic or traditional water tank.
Try this: if you have this type of tank, remove the valve step cap covering the bladder inflator valve located on the top of the tank. Using a small implement, MOMENTARILY (just for a second) depress the valve pin in the center of the valve stem down to see if air or water comes out. If water comes out of this valve the air bladder has burst.
But the bladder could be burst but blocking the valve in which case nothing will happen. If air comes out of this valve the the tank bladder contains air and may not have burst.
If air comes out of the valve, use an accurate tire gauge to check the air pressure at the valve.
If the air pressure is 4 psi below the well pump cut-in pressure then the air bladder is probably fine. If the air pressure is less than that figure, using a bicycle pump, just add a little air to the bladder until it is set to the proper number - 4 psi below the pump cut-in pressure.
Draining the water tank itself and adding air to a bladder type tank itself through the (ruptured) bladder valve at the tank top of a tank with a failed bladder MIGHT work to improve performance for a while (until the air is reabsorbed back into the water over time) but you need to replace the bladder.
A guide to replacing the air bladder in the WellMate captive air tank is provided by the company at http://www.wellmate.com/pdf/Residential_AirCell_Replace_Instructions.pdf
The air bladder in the WellMate™ type water tank is to be inflated to 4 psi below the well pump's "cut-in" pressure.
The installation manual for this tank is at http://www.wellmate.com/pdf/Residential_CaptiveAir_Tank_Install_Manual.pdf
The tank has a 5 year warranty so check your records of when the tank was purchased to see if that applies.
Type 2 tanks, described by WellMate as hydro pneumatic water tanks, do not incorporate an internal bladder but rather an air volume control valve that replaces air into the tank as needed. These tanks will perform better than older steel water pressure tanks because we don't face the concern of rust perforation of the tank.
If the air volume control (AVC) fails, the tank will act much like a type 2 tank
See TANK TYPES: WATER, OIL, EXPANSION, ALL and scroll down to the description of older steel water tanks. In this case you may need to replace the AVC.
Draining and adding air to an AVC type tank with a failed AVC also MIGHT work to improve performance for a while (until the air is reabsorbed back into the water over time) but you need to replace the AVC.
Water tank bladder air pressure adjustment: also review WATER TANK BLADDER PRESSURE ADJUSTMENT if you are adjusting, tuning, or replacing the air pressure in your bladder-type well tank.
How can l tell which pressure tank l have - with Bladder or without. I have CBAKX on the tank. 42 gallon upright A drain plug at the bottom an inpipe an out pipe and a pipe for pressure gauge. - Oliver 9/10/12
Oliver, see WATER TANK CAPTIVE AIR vs TRADITIONAL WellMate for a comparison of these two types of water pressure tanks.
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 PUMP REPAIR GUIDE
Or see WATER TANK: USES, TROUBLESHOOTING - home
Or see these
Water Tank Articles
- AIR VOLUME CONTROLS, WATER TANK
- FIBERGLASS WATER TANKS, BLADDERLESS
- WATER TANK AIR, HOW TO ADD
- WATER TANK AIR VOLUME CONTROL REPAIR
- WATER TANK BLADDERS & CAPTIVE AIR
- WATER TANK CAPTIVE AIR vs TRADITIONAL WellMate
- WATER TANK CONTROLS & SWITCHES
- WATER TANK DIAGNOSTIC FAQs
- WATER TANK DIAGNOSIS & REPAIR
- WATER TANK, LARGE CAPACITY
- WATER TANK LIFE EXPECTANCY
- WATER TANK PRESSURE ADJUSTMENT
- WATER TANK PRESSURE GAUGE
- WATER TANK PRESSURE RELIEF VALVE
- WATER TANK PRESSURE SELF-INCREASE
- WATER TANK REPAIR PROCEDURES
- WATER TANK REPLACEMENT
- WATER TANK, ROOFTOP
- WATER TANK STEEL
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Recent questions & answers about Well Mate Pressure Tanks, fiberglass pressure tanks & tank repairs
On 2017-03-19 11:01:29.143396 by (mod) - replacable air cell or "bladder" in a WellMate pressure tank
Yes, your wellmate pressure tank uses a replaceable air cell. Contact Wellmate at the address or website given at the end of WATER TANK CAPTIVE AIR vs TRADITIONAL WellMate
On 2017-03-19 10:35:19.191337 by Murugaiyan
In my pressure vessel Model WM0450 bladder got damage. Is it possible to replace new one.
On 2016-04-22 23:00:04.892954 by (mod)
Ellie if you are having repeated pressure tank failures something is wrong. But if the problem is simply loss of the air charge, it sounds to me as if an automatic air volume control is missing or not properly installed.
On 2016-04-22 22:28:48.321498 by Ellie
What can you do if the pressure tanks keep going out-needing to be replaced because they are full of water-about every 5-6 months? Nobody can figure out why. They are still under warranty and are installed by a knowledgeable well person.
On 2015-07-17 19:36:03.731471 by (mod)
It is normal for a pressure tank to fill only part-way, as the air charge in the top of the tank occupies the remaining space.
On 2015-07-17 18:27:09.843308 by TB
Our wellmate UT-120 tank is only partially filling up. How can we correct this?
On 2015-05-26 19:16:22.438990 by Ginny
Water comes out of the valve on top of the pressure tank, what does that mean?
(May 4, 2014) Harry said:
I have a fiberglass bladderless water pressure tank through which I pump water through a filter system then to a rooftop storage tank which then supply the building by gravity flow.
The bladderless tank has a valve on its side to allow air to enter the tank. How do I know when the tank has too much water and so needs draining to let air in?
Harry, if the water tank does not have enough air (that is it's waterlogged) you'll notice it because the pump will cycle on and off rapidly.
See WATER PUMP SHORT CYCLING for details.
(Sept 22, 2014) Anonymous said:
can you tell me if a wellmate pressure vessel wm330 is suitable for outside weather conditions, i.e. -10c to 30c. thanks
Anon any water pressure tank needs to be protected from freezing. You can locate the tank in a well pit below the frost line or construct a heated enclosure.
See WELL PITS
(Sept 28, 2014) deanpeddle said:
I have a wellxtrol tank by amtrol and a submersible pump in my shallow well. my pump will run (and push water) if i manually hold the bypass lever at the 'auto' position but always shut off when released. the tank has NO WATER in it at all.
I replaced the pressure switch and cleaned out (it was blocked) the small inlet line the pressure switch is mounted on. could a blockage in the line going to the tank cause the problem i'm having with the pump not cutting in at all?
Yes you are correct. But check first for a debris-blocked pressure sensing port on the pressure switch.
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