Water pump and pipe size for maximum water intake?

Question

• Each floor is 12 feet in height.
• I already have the pump (Centrifugal Regenerative Self Priming 1HP Peripheral Type, Self Priming - 180sec At 3m STATIC SUCTION LIFT) and would like to know which is the best location to install it for maximum water intake to the overhead tank. The water Supply is only available for a limited period everyday and the goal is to achieve maximum water to the overhead tank.
• The Water supply line provides water from a bigger (8inch) main line but water pressure from it is not adequate to pump up water on top level. (Water pressure only enough to supply water to first floor and that too with reduced pressure.)
• The water pipe from main supply to pump and from pump to overhead tank is 1/2 inches wide.

Questions:

1). Which position of the water pump in the above situation provide maximum water output to the overhead tank?

2). Will using thicker 1 inch pipe after pump (the input will remain 1/2 inch) make any difference to suck maximum water in?

Answer 1

To achieve the maximum flow keep your pump at ground level. With a 1/2" slightly pressurized intake it may help to put 3/4" out put to the water tank but much larger would probably be a waste of $. Make sure to have water in the pump at all times the shaft seals are usually ceramic with no water they overheat and crack. This would be another reason to keep the pump at ground level since there is low water pressure it will be difficult for the pump to prime. If you do have pressure on the 2nd floor it may work ok there if the pump max head pressure cannot make it to the roof. If memory serves fresh water weighs .43 pounds per foot so you will need the pump to be able to push a minimum of 25 psi for any flow from ground level to the top of the tank. I have a firend that gets water from a spring he pumps the water ~65' up the hill to a large tank and he has right at 30 psi in his cabin.

Answer 2

i think as you are using centrifugal pump you will get the same flow rate despite of what size of pipe you are using with less or more power consumption and also to get npsh it will be better to install pump on ground level.so, if you want to increase flow rate you would nead high flow rate pump or have to increase the motor speed by using VFD.