There are two primary reasons for having a pressure tank in a pumped water system -- to give the pump motor time to dissipate the extra heat energy generated each time the pump starts, and to store water under pressure so the pump does not have to come on every time there is a small, intermittent demand for water.
A few years ago, I was asked to look at a booster system. The pump was not performing according to design, and was noisy. When I disassembled the pump, I noticed extensive pitting in the vane area of the impeller .... The prime suspect was cavitation erosion.
We began this section on friction loss pressure drop last month with a look at the factors that contribute to friction loss. This month, we will use this information to calculate the pressure drop due to friction loss in a typical residential system.
Last month, we examined two of the three factors to be considered when determining the pressure requirements of a pump, household working pressure and lift pressure. The third factor is pressure drop due to friction loss.
There are three factors that go into determining the pressure required from a pump in a residential water system – lift pressure, household pressure and friction loss.
Sizing a residential water system involves several considerations. You will need to know the amount of water required, the vertical distance the water must be lifted, how much pressure is needed to overcome friction and more.