Before putting hydraulic or lubrication systems into service, the entire system should be flushed. Depending on the application, low viscosity flushing oil or the actual operating oil may be used. The purpose of flushing the system is to protect system components externally via mobile filtration units to ensure residue from assembly is removed. However, these mobile filtration units are also used to for the initial system fill or when changing the oil. The filtration units are quiet and compact, with an easy to transport design.