Re: Should I replace my pressure tank?
Posted by David. on June 09, 2003 at 23:42:04:
In response to Re: Should I replace my pressure tank?
I have some instructions from a plummer and have been following them exactly. First, I check the pump-on pressure. (42PSI) Then I remove all water and air from the tank. (Pump power is off at the fusebox). I drain the last from a valve at the bottom of the tank. The valves from the tank to the house are closed. I then pressurize the tank from my air compressor to 40 PSI. I then turn the pump on and it fills the tank to 62PSI and then turns off. I did this tonight actually and afterwards, I measured over 9 gallons before the pump turned on again. I also timed the pump from turn-on to turn-off and it ran for 53 seconds. Keep in mind that this time was for a freshly charged tank. The pump run time decreases as time goes on and the air is desolved in the water. I do not think the pump has ever run for one minute or more.


: Since there is no barrier between the air and the water, I am not sure how you can determine what the air volume, not pressure, really is. With a bladder tank, the pressure is checked without water in the tank. Without the bladder, the only way to charge the tank would be with water in it and that would affect the reading immensely.If there were no air in the tank, then it would fill with water and operate every time a faucet was opened. With a bladder tank, if the pressure were above the cut-out point the pump could not overcome it, so no water would enter the tank and the same thing would happen. If the air pressure is set above the cut-in point then the tank will run out of water just before the pump starts and there will be a micro second when there is no water flow at all. The ideal situation would be to have the air bubble in the tank exactly the size to completely drain the tank and the pump start at just that moment. It is difficult to arrive at that point so the pressure is set just below that level by 2 or 3 pounds. Without a captive air bubble, creating the ideal one is a hit or miss proposition, which could be why you only get the draw down you do from the tank. Do you pressurize the tank with the pump off and until the pressure is about 35 psi and air is flowing from the faucets?

: : I'm not sure of the capacity. The tank is 50" tall and 16" wide. It has the air valve on the side but it's located almost at the top of the tank. When we moved into the house 10 years ago, the tank pressure was set to 40-60. Since I installed 2 in-line whole house water filters and a water softener, I adjusted the pressure up a bit to compensate. There is approx 3 PSI difference between the tank pressure and the pressure after the filters. (I installed a gauge there). I recharge the tank to 2PSI below the cut on pressure. There are no problems at all with the tank, the pressure at the fawcets or the well pump. I think I am just looking to possibly get more life out of the pump (located 93' deep) before it dies. Maybe I am paranoid!!

: : : How large is the existing tank? If the air pressure charge is too high or too low you will not get the maximum water draw down before the pump starts.

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