we have a problem on our purifier of Auxiliary engine for lube oil. During Feed valve open there is No pressure registering ang we have noticed that there is no flow of clean oil to the discharge pipe of our purifier. Although the feed pressure or the dirty oil oil inlet is okay and has flow,the feed pump pressure is okay still there is no dicharge of clean oil to the discharge pipe. we have already replaced all gasket of the bowl. we also observed that during feed valve open the oil that is being separated flows directly to the sludge discharge. and also during sludging during ejection of the bowl it seems to be that the annular piston or the sliding piston is not moving but there is a flow of water and the pressure is okay. what should we do or check for possible cause and how can we resolve this problem. Thank you