# How can I tell if the bladder in my water tank is damaged?

I have a "Signature 2000 SR35-10S-01" water tank. Trying to determine if my pump is cycling too fast and if my tank my be to blame. The pump switch is set for a 40/60 pressure range. With a kitchen tap running at full, the pump goes on when the water pressure drops to 40 and it takes 20 secs to reach 60, and then pump stops. Then it takes about 1min/10 secs for the pressure to drop to 40 at which point the pump kicks back on. This of course repeats while the tap is open.

So pump on for 20 secs, pump off for 1 min/10 secs with a kitchen tap running. Is that considered too fast? What should be happening here if there's not a problem.

I checked the pressure of the "air cell" with a tire gauge at the schrader valve at the top of the tank (under the cover). After emptying the tank totally I get no pressure reading. If I turn the pump on and let the tank fill I get a pressure reading that matches the current water pressure (40-60).

One thing that makes me think the the "bladder" or "air cell" (they're the same thing right?) is damaged is that if I want to drain the tank of water completely it takes quit a bit of time to do so after the cutoff of 40psi is reached.

So what I think is happening is that I'm filling the whole tank up with water instead of filling it against an inflated bladder/air cell.

Any help/opinions on this greatly appreciated!

• Not really familiar with these, but the theory makes sense to me given what you're seeing. On the other hand, even if the bladder was working properly, you would expect the pressure there to stabilize at the same as the water pressure; if they weren't, the bladder would compress or expand until they did. Commented Sep 28, 2014 at 17:32
• Since someone bumped this old question, have a relevant answer to a similar question: diy.stackexchange.com/a/106893/18078 Commented Dec 6, 2023 at 3:48

If you measure 0 psi when the tank is empty, it means the tank is not charged. Try adding air through the Schrader valve. If you can't get the pressure to increase and hold, the bladder is bad.

If you measure the pressure at the Schrader valve when the tank is connected to the plumbing, you'll always measure the water pressure in the plumbing. The tank must be isolated from the plumbing, to measure the air charge pressure.

• Check to see if there's some sort of sticker or dataplate near the Schrader valve that tells you what PSI to pressurize the bladder to. As noted, it should hold this pressure with the tank emptied of water. Commented Sep 30, 2014 at 17:53

I have the same tank. The factory pre-charge is noted on the sticker containing the model number and serial number. On mine it is 30psi.

To empty the tank, turn off the pump and open a tap. Using an air hose with a gauge, periodically pressure up the tank to 40 or 50 psi. The higher pressure will bleed the tank faster. If you empty the tank with the pressure above 30 psi, bleed off some of the air.

At some point you may get air coming out of the tap. If it continues and the pressure reading drops to zero, there is a hole in the bladder. If just a little air comes out, shut the tap and restart the pump.

The bladder is not totally impermeable, so after a few years there may be some water in the bladder. If there is a lot of water inside an undamaged bladder, this procedure will not solve the problem totally. If you feel the system is still not performing well, take the tank out, remove and empty the bladder and reinstall it after careful inspection.

If I remember right, bladder tanks come precharged at 5 PSI when empty. Try bringing up the pressure through the Schrader valve with an air pump. What you describe is what is called a water logged tank. The pressure you add back in may only be temporary, but it should fix the pump short cycling until you get it replaced.