Water Tank FAQ

Questions & Answers

What is a bladder pressure tank?
It is a type of tank containing pressurized air and water separated by a membrane (bladder). They are precharged with air at the factory.
What is the average life of a bladder tank used in residential domestic systems?
On average, a bladder pressure tank lasts 6-8 years.
What functions do bladder pressure tanks serve?
Maintain a desired range of water pressure in the distribution system. Minimize pump cycling, preventing frequent starts and stops protecting facilities from damage. Protect against water hammer.
How to check the bladder pressure tank air charge?
Disconnect electrical power to the pump. Drain the tank by opening the closest faucet. Check tank pressure by placing a tire gauge on the air-charging valve on top of the tank. Add air if the pressure is less than 4 psi below the pump cut-in pressure (lowest pressure in the range). Use a tire pump or air compressor. Use caution with an air compressor. Release air if the pressure is more than 4 psi above the pump cut-in pressure. Check for leaks in the air charging system. Use a soap solution to check the air-charging valve for leaks. Re-start the pump and run through a normal cycle to verify the setting.
What is a waterlogged pressure tank?
A tank is waterlogged if it is completely filled with water or has too much water to function correctly.
What happens when you have a water logged tank?
The pump motor cycles – turns on and off – too often. Frequent cycling can shorten the lifespan of a pump. Waterlogged tanks contain stagnant water that can contribute to bacterial problems or taste and odor complaints. Causes premature tank failure.
What happens when the bladder inside the tank has ruptured?
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.
How do I test to see if the bladder has ruptured?
Remove the valve 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 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 tank bladder contains air and may not have burst.
What do I do if the bladder has ruptured?
The bladder can be replaced, but we find replacing the bladder expensive and labor intensive, therefore we do no sell replacement air cells. We suggest replacing the tank
What does it mean if air comes out of the valve when I depressed it?
If air comes out of the valve, drain the water from the tank; 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, use a bicycle pump to add a air to the bladder until the pressure reaches 4 PSI below the pump cut-in pressure.
What is tank drawdown?
Drawdown refers to the amount of water that evacuates the tank before the pressure switch will activate the pump. Drawdown is a affected by the pump, the size of the tank and the pressure settings that govern your water system.
What is Drawdown or Acceptance Factor?
It is tank drawdown expressed in percentage. Example: The acceptance factor of a bladder tank with a pressure setting of 30/50 PSI is 30% (0.30).
What is the warranty on Wellmate tanks?
All WM Wellmate tanks carry a five year limited factory warranty for potable water residential installations and 2 years for non-residential installations.
Does the warranty cover labor?
No, unfortunately there are number of factors that can contribute to a failed tank and the only factor that Wellmate can insure is the tank.
My tank was just installed and the water has a funny taste – what should I do?
Flush the new tank by allowing water to flow through three or four pump cycles. If the taste continues, you should probably have the source water tested.
Can I use chlorinated water with my Wellmate tank?
Of course. Wellmate tanks are designed in the knowledge that chlorine is often used to periodically treat a well.
What is a cycle?
A cycle refers to the pump run time. A cycle starts when the pump starts and a cycle is completed when the pump stops. Pump starts and stops are determined by the pressure settings of the system. Below, we demonstrate a tank’s drawdown feature that assumes a water system with a 30/50-psi pressure setting. This means that the pump will start (“cut-in”) whenever the pressure inside a tank is reduced to 30 PSIG and will stop (“cut-out”) when the pressure reaches 50 PSIG . Common pressure settings are 20/40, 30/50 and 40/60.
How does a pressure switch control the pump and tank?
The pressure switch communicates with the tank and the pump. The pressure switch monitors the pressure inside the tank and activates and de-activates the pump when cut-in and cut-out pressures are reached inside the tank.
What is pre-charge pressure?
Pre-charge pressure refers to the amount of air in PSIG that is pumped into a tank prior to installation – usually at the factory. Most tanks are provided with a 28-psi pre-charge. The pre-charge is the “spring” that helps to create water pressure. As the diaphragm fills with water, it compresses the pre-charge. In a 30/50 system, the pump will continue to propel water into the tank until the pressure in the tank reaches 50 PSIG
How much pre-charge should I have in my WellMate tank?
Your tanks should be pressurized to 4 PSIG less than the cut-in pressure setting (for example, if your pressure settings are 30/50, then you cut-in pressure setting is 30 PSIG and your tank should have a 26 PSIG pre-charge).
What is the construction of our pressure vessels?
The vessels have a polyethylene liner with a winding on the outside of continuous strand fiberglass and Epoxy Resin.
How do you check or change the air cell pressure?
To check the pressure in the air cell, the power supply to the well pump must be turned off and the water must be drained from the pressure tank.. With the pump turned off and the water drained from the pressure tank a standard tire gauge can be used on the valve stem at the top of the tank. The pressure in the air cell should be 4 psi lower than the pump cut-in pressure.
What are the operating parameters of the Wellmate pressure tanks?
The maximum external temperature is 120 deg. F. the maximum internal temp. is 100 deg. F. the minimum operating temp. is 40 deg. F. The maximum allowable vacuum is 5 inches of mercury. Operating pressure varies with the size and application.
Can the air cell be replaced in the Wellmate pressure tank?
The air cell can be replaced, but the pressure tank must be removed from the system and disassembled. Instructions will come with new air cell……but….we find replacing the air cell expensive and labor intensive, therefore we do no sell replacement air cells.
I’ve heard these called “pre-charged” tanks, “bladder” tanks, “captive air” tanks, etc. What is the right name?
Any of these names are fine. We call them “Pre-Charged Pressure Tanks” or “Bladder Tanks”
What is the difference between a “pre-charged pressure tank” and a regular one?
A pre-charged bladder style tank has a bladder inside of it that is made of vinyl. The bladder is surrounded by pressurized air. The well pump will push water into the bladder under pressure. When the pump shuts off, the water is held inside the tank by a one-way check valve in the piping system. When someone opens up a faucet, shower, etc. the air pressure inside the tank will squeeze on the bladder and force the water out.
Is a bladder tank the same as a diaphragm tank?
No. The bladder tank has a vinyl bag inside of it. The diaphragm tank has a vinyl or rubber flat diaphragm mounted in it – usually about 2/3 of the way from front to back. If you look at the steel tank, you will see a seam around the outside of it. That is where the diaphragm is. The function of the diaphragm and bladder tanks is the same. Compressed air on one side of the diaphragm pushes against the diaphragm and the water on the other side of it.
Is there an advantage in using one of these tanks instead of the older style standard air-over-water tanks?
The primary advantage of a pre-charged tank is the physical size. Because it holds compressed air, it can do the same job as a much larger standard air-over-water tank.
There is only one pipe connection on this tank. How does water get in and out of it?
When the tank is connected, a tee will be installed either at the tank or at the pump. The tee has a total of three connections: One goes to the pump, one goes to the tank, and one goes to the household plumbing system. Water from the pump can go either into the tank or directly into the household plumbing. When the pump is not running, the water comes out of the tank into the household plumbing.
How big of a tank do I need?
When it comes to pressure tanks, bigger is better. The whole idea of having a tank is to store water under pressure so it’s ready to use in the house. It prevents the pump from having to turn on every time a little water is needed. One of the biggest factors in shortening a pump’s life is frequent starts. Having a big pressure tank means that you have that much more water stored. It means the pump will not have to turn on for a longer period of time. That helps prevent the pump from having to start often. In short, when it comes to choosing a pressure tank, you want to buy as big a tank as you can afford and have room for.
Can I connect multiple tanks together to get more storage?
Yes. You would put a tee into each tank connection. You want to put your pipe in from the pump, s well as the pipe out to your household plumbing, close to the middle of your tank set. This will help allow the tanks to be used more evenly.
I don’t have much pressure in the house. I think the tank is the problem, right?
Many people think that the tank makes pressure but it does not. It only holds the pressure that the well pump puts into it. It’s kind of like a balloon. If you lay a balloon on a table, it does not inflate itself. It cannot create the pressure. In order to get pressure into it, your lungs need to blow the air into it. Now it can hold the pressure. The water tank is the same. The pump has to put the pressure into it.
There is an air valve (like a tire valve) on top of the tank. Do I need to check pressure or something?
YES, The tank comes with a pre-charge from the factory but you need to set the air pressure when you install the tank. For steel tanks it needs to be set to 2 psi less than the turn-on pressure that your pressure switch is set to. For fiberglass tanks It needs to be set to 4 psi less than the turn-on pressure that your pressure switch is set to.
How often should I check the tank pressure?
The tank pressure needs to be checked AT LEAST twice a year. It is better to check it every-other-month. There are instructions in the owners’ manual on how to do this. You will want to have a good accurate tire pressure gauge to do this. It uses exactly the same type of valve that’s on your car or bicycle so the same kind of tire pressure gauge will work fine.
How do I add air if it’s low? Use a bike tire pump or something?
Adding air to the tank is exactly like adding air to a car tire. A portable air compressor will be MUCH easier than any kind of hand pump. The volume of air inside a tank would mean a LOT of pumping by hand.
What happens if I don’t check the air pressure regularly?
Just like the tires on your car, air pressure can slowly leak out of the tank. The air pressure is what keeps the bladder from over-expanding from the pump’s pressure. If too much air pressure leaks out of the tank, the water pressure will over-expand the bladder so much that it can burst. At that time the bladder, or the tank, needs to be replaced.
I have a small pipe feeding me water from the city. My pressure drops off when I use a lot of water. Can I use one of these tanks so I can just store extra water inside my house under the city pressure?
Yes you can. Where the water pipe comes into your home, install a check valve. You don’t want your water going back out to the city. Check your city water pressure at a faucet, etc. to find out what the city water pressure is. Set the pre-charge in your tank to 70% of the city water pressure.
My water pressure at the faucets and shower drops off to nothing, and then it surges back on. Is that a tank problem or a pump problem?
In most cases, it’s a matter of the pre-charge air pressure in your tank being set too high. Check the pre-charge air pressure in your tank (according to the directions in the manual) and set correctly.
Can I use a bladder style pre-charged tank to hold the water that my Reverse Osmosis filter system puts out?
No. RO tanks have bladders made of butyl rubber. Ours are a type of vinyl. RO water is so very pure that it wants to pull contaminants into it. If stored in the vinyl bladder of a pre-charged tank, the “elastomers” in the bladder will be pulled out of the bladder into the water leaving the bladder very brittle. What it pulls into the water can also be considered to be toxic.
I don’t have any water when I open a faucet. My tank is bad, right?
No. The tank only holds water that the pump puts into it. If the pump doesn’t put any water into the tank, then it doesn’t have anything to hold. If you get NO water when you open a faucet, check your pump.
My water smells funny in the house. Is that because of the tank?
There are certain types of bacteria called “anaerobic bacteria” that can grow where air does not touch the water. If your well has this kind of bacteria in it, the bacteria can start to grow once it gets inside the bladder since that water is not touching air. This bacterium is usually harmless but you should have your water tested for things like iron bacteria or sulphur bacteria.
How do I get rid of those bacteria?
Some people will tell you to chlorinate your well but that will only work for a short time. There are only two real solutions here: 1) Install a “contact tank” with a chlorine dosing system. This type of system injects a small amount of chlorine into the water as it comes into the house. The chlorine kills off the bacteria so it can’t grow in your tank. 2) Switch back to the older technology of an air-over-water standard tank. In that kind of tank the air touches the water and these anaerobic bacteria cannot grow.
What is the tank’s equivalency rated size?
The Equivalency Rated Size” is a comparison to an older-style air-over-water tank.
What is the tank’s actual capacity”?
The tank’s actual capacity is how much the physical tank would hold with no bladder in it.
What is the tank’s drawdown?
The tank drawdown is the amount of usable water that can come out of the tank between pump cycles.
Which one is really most important to ME, the equivalency rated size, the actual size or the tank’s drawdown?
If you are replacing an older air-over-water standard tank (atmospheric tank), the “equivalency rated size” is important. You would want to pick a tank that is at least the same size as the one you took out, preferably larger. The other rating that’s important is the “Drawdown”. This is how much water can come out of the tank between pump cycles and it is how much water the pump has to put back into the tank when it has to run. This is the number you want to look at so you can figure out the run time of your pump. You want to choose a tank large enough that the pump has to run a minimum of 1 minute, preferably 2 minutes, each time it runs. So choose a tank with a “drawdown” that is the same or larger than the GPM rating of your pump.
I tried to check the air pressure in my tank and water came out of the valve. What’s that mean?
If you get water out of the air valve stem, it means your bladder has failed. Water has left the bladder and is up above it in the tank. It is now time to replace the bladder or the whole tank.
Should I winterize the domestic system pressure tank?
Water in a tank left in a dwelling without heat over the winter can damage the pressure bladder or even cause the tank to rupture. One of the most important tasks in colder climates is winterizing your well's pressure tank. Winterizing the tank is a simple process that requires no tools and takes only a few moments to complete
How do I winterize a pressure tank?
Turn off the electrical power to the well pump. Attach a garden hose to the pressure tank drain valve . Place the end of the hose to a drain Open the drain valve and empty the tank in the tank water. Remove the hose from the tank, Allow any remaining moisture or condensation to escape by leaving the drain valve opened. Place a container under the drain to protect against damage by dripping water. Place a portable heater next to the tank for at least 30 minutes to restore flexibility to the plastic bladder before restoring water. Plastic becomes brittle when cold and sudden application of water pressure may cause the bladder to split or crack and lose its ability to retain air.
Should I use antifreeze when winterizing my potable water system?
Do not use antifreeze in any potable water system. Antifreeze is a toxic substance that should only be used in automotive cooling systems.

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