Does pressure affect Well Xtrol tank bladder life?

[grider]

I have a brand-new 85 gal Well Xtrol bladder tank and upon installation increased the air pressure above the bladder from 38 psi to 46 psi since my pressure switch is set at 48-68 psi. Will this increased tank pressure over the 38 psi default level decrease the life of the bladder? (Under normal conditions, the pump is not over-cycling.)

Thanks!

[valveman]

I use those same tanks with a pressure switch setting of 100/120. As long as the air pressure is just under the pump start pressure, you won't over stretch the bladder. Bladders are busted from going up and down like bending a wire till it breaks. This happens as the pump cycles on and off. "Normal cycling" means the bladder will last an average of 7 years. "Over-cycling" will cause the bladder and everything else to wear out sooner. The less cycling, the longer the bladder and everything else will last. The higher the pressure setting, the less water the tank will hold. At 40/60 that tank holds about 23 gallons, at 48/68 it only holds about 18 gallons, that is what causes more cycling.

[grider]

Thanks for the info. Will the water pressure delivered both to my house and my irrigation system suffer if I lower the pressure to 40-60 psi in order to reduce cycling?

[valveman]

I don’t know that 40/60 would be considered suffering for pressure, that is a matter of personal preference. 40/60 equals 23 gallons, 48/68 is actually 20.8 gallons so, that is not what will make much difference in cycling. No matter which pressure you decide on, the only way to eliminate cycling is to match the long term uses to the size of the pump, or to use a CSV.

In other words, if you have a 20 GPM pump, every sprinkler zone needs to be at least 20 GPM or the pump will cycle. A CSV will make the out put of the pump match any amount of water being used down to 1 GPM, without the pump cycling.

[Gary Slusser]

The primary cause of pre-charged type pressure tank failure is not keeping the air precharge pressure set where it should be.

[valveman]

Which came first, the chicken or the egg? I think cycling is the cause for most bladder failures. However, excess cycling can also be the reason for losing the air charge. When the pump is off and you are getting water from the tank, the air pressure is higher than the water pressure, which lets the air permeate through the bladder. When the pump is running, there is more water pressure than air pressure and the air can't get through the bladder. The fewer times it cycles, the less opportunity the air has to get out. Low air pressure will over stretch a bladder, cycling breaks a bladder like bending a wire back and forth. Both problems are caused by cycling.

[Gary Slusser]

After decades of thinking about this, sometimes late into the night, I say the predecessor to the chicken came first and it produced an egg that was different than the parent and that created the first chicken as we know them... lol

Air escapes from tires, even if the tire and its wheel isn't on a vehicle, so air in a pressure tank escapes and should be checked at least annually. The same for tires but they should be checked monthly. Under inflated tires cause many problems with the operation and maintenance of any vehicle, same for a pressure tank bladder. IMO flexing of a bladder, usually neoprene, a very tough material, or in pneumatic type tires of any kind, cause the escape of the air but flexing rarely causes tire or bladder failure IF the air pressure is correctly maintained. Under inflation causes excessive stretching of tires and bladders, and to me, that causes them to wear and fail prematurely. And no I don't know if it was the chicken's parent or its egg that came first but I believe it all came from a few cells that got together a******ly somewhere in a pool of soupy water in prehistoric Africa or probably China. Maybe Antarctica since it's covered with a mile thick ice'n snow and we haven't poked our colletcive noses around there much yet.

[grider]

Thanks to all for the enlightening (and at times philosophical) discussion on pressure and cycling!

grider