chong

There are many variables affecting pump performance. Without knowing your piping set-up and your equipment specifications, anyone giving you an opinion at this point is only giving an educated guess. The best thing to do in connection with your question is to at least draw a piping diagram that shows the well, the length of the pipe from the well to the pump (horizontal and vertical), from the pump to the tank, and the tank to the farthest and highest outlet (faucet, shower, etc.) so that you can calculate the overall distance that the water is lifted. You also need to show the location of any accessories (valves, filters, etc.) wherever they are on the pipeline. You will also need to give the specs on the tank (height, diameter, or volume) and how high above the pump it is. Then you need the pump specs, i.e., the rate of flow (GPM) at what pressure (usually given in maximum feet but sometimes given in PSI, or the metric equivalent). Pumps are usually rated at different pressure conditions, such that as the pressure goes up, the GPM goes down, or the manufacturer will give you the pump curve, or both.

The tank specs also will say what the pressure it was pre-charged at. This is the pressure that the pump is set to cut off at. Usually, as a previous responder stated, there is an air pocket, whether in or outside a bladder inside the tank, that is pre-charged, so that as the tank fills up, the water compresses the air in that tank, up to a limit.

If you can sketch up your installation with dimensions, including your pipe sizes and all the info above, I'd be happy to take a look at your system.

Chong