A heat radiating unit for adapter includes at least one receiving portion and a heat radiating portion. The method involves supplying a fluid flow at different pressures and sensing fluid flow characteristics in at least one location at each pressure. An oil reservoir is formed in a crankcase journal wall, that journals a crankshaft of the engine. Selected liquid drops are caused to deviate from the first path and begin travelling along a second path using a deflection mechanism. If no blockage is present between the reduced pressure source and the tissue site, the differential pressure is limited to a second maximum differential pressure.