Assuming that the total value is in cell A2 and percent in B2, the above formula turns into a simple =A2*B2 and returns 104.50. Remember, when you type a number followed by the percent sign (%) in Excel, the number is interpreted as a hundredth of its value. For example, 11% is actually stored as 0.11 and Excel uses this underlying value in all formulas and calculations. In other words, the formula =A2*11% is equivalent to =A2*0.11.
from my understanding, shut off pressure is the the higest pressure that can be produced by a pump and this happened at zero flow i.e. control valve closed at discharge line. so when pump running during discharge valve closed, the pressure build up in the pipe line until a maximum pressure and this maximum pressure is shut off pressure.
1 Turn the pump off at the switch and shut any taps on your supply. 2  You want the air in the tank to be approx. 3  70% of the off pressure. 4  For example your pump builds up pressure and shuts off at 500kpa, then the pressure drops and it turns on again at 200kpa. Work out what pressure your pump is turning off at (high pressure) and on at (low pressure) from its pressure switch. 2  Make sure there is no water pressure in the system as this will give you a false reading on the air pressure. 3  Turn the pump off at the switch and shut any taps on your supply.