Re: Water Pressure tanks
Posted by Jon on April 18, 19100 at 23:54:38:
In response to Re: Water Pressure tanks
Sounds like you have a simple galvanized tank. I have a similar setup, and had to do this with my irrigation well. Its dead simple. You drain it. Water is incompressable. The air in the tank is what compresses as the pump runs. The pump will be set to turn on when the pressure falls to a certain level (often 20 PSI), then run until the pressure reaches a higher level (often 40 PSI). A waterlogged tank means the air in the tank has been absorbed into the water, and the tank is almost full of water. The small volume of air compresses quickly, so the pump only runs a very short time once it starts. The air also decompresses quickly, so the pump kicks in quickly, too. If you're running the water, the pump will cycle very quickly, resulting in a quick death. I saw a rule of thumb that the pump needs to run at least one minute once it starts, though I don't know the validity of that rule.

Using a bigger tank means a larger volume of water between the cut in and cut out pressures. That means slower cycling, and longer pump life. More modern tanks have a bladder or membrane that separates the water and air, and don't get waterlogged unless the membrane brakes.

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