Re: Well-Xtrol Expansion tank
Posted by Gary Slusser on January 10, 2003 at 11:16:18:
In response to Re: Well-Xtrol Expansion tank
: Is there any sizing for expansion tanks? I believe they are called expansion tanks. They reside in the water delivery system and help maintain water steady water presure and keeps the pump from extra cycling off/on. Is there a limit to the size or number of tanks in the system?

They are called pump pressure tanks. And many folks mistakenly think bigger is always better but that�s not true. The pressure tank is supposed to be sized to allow the pump to run for a minimum length of time to provide adequate cooling of the motor. Usually that is one to two minutes (per manufacturers) but depends on the size of the pump and voltage of the pump. The amount of water delivered during that 1-2 minutes depends on the well static water level and the pump and the plumbing system to the tank among other things, like the pressure range the pump is used at. If you use too large a tank, the well will be drawn down too far and you can cause a dry well condition which means the pump sucks air, and you have no water until you allow enough time for the well to recover.

So, without knowing the specifics about your well and pump and its delivery rate at the pressure tank, no one can tell you how large a tank becomes too large for your water system but there is a limit. And with larger tanks you have more stagnant water that then warms to room temperature.

The type of well you have is another limiting factor as to how much water you can draw out of it at one time without causing a dry well condition and/or water quality problems such as dirty water or higher concentrated levels of the causes of water quality problems such as iron. Where the pump is placed in the well is another.

So my advice is to check your gpm delivered at the tank and size your pressure tank to allow the pump to run 1-2 minutes. And that should be done with the proper air pressure in the tank for your pressure switch settings (range used; 29-28 air psi for 30/50 etc.) when there is no water in the tank.

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