l have a pump rated at 4m3/h and 35m head. lt pumps edible oil through an economizer and the to dearator with some nozzles. From the dearator there is another pump feeding a vessel (rated 9m3/h and 40m head) and there is a flowmeter reading 1800L/h (1.8m3/h). Some how the dearator gets empty or starved with oil. My question is how so as the dearator pump is just pumping 1.8 m3/h from the dearator, while the one feeding it is feeding at a rate of 4m3/h. see attached schematics