We have two series connected 2.2 kw (3HP) centrifugal pumps used for domestic water supply from ground floor to over head tank at 25 m high. Delivery line has 100 mm dia. reduced to 40 mm dia. GI pipe If we change the 40 mm dia. GI pipe to 75 mm dia. GI or PVC pipe, will there be any saving on pumping time?