waiting for the lack of flow to be sensed by a separate no flow sensor fig6 12 show an alternative embodiment of a popr valve 600 with fig6 and 8 showing the popr valve 600 in the closed position and fig7 and 9 showing the popr valve 600 in the open position fig1 shows an exploded view of the popr valve 600 popr valve 600 includes a main housing 602 and an end cap 604 fig1 shows a pictorial view of end cap 604 as shown in fig6 and 7 main housing 602 includes a hollow male threaded end 605 that is threaded into a lubrication system component 640 and provides an inlet 611 for high pressure fluid the high pressure fluid exerts a force against a piston 612 that can slide within a hollow cylindrical sleeve 614 press fit end cap 615 in the shape of a plug with a longitudinal slice removed fig1 keeps piston 612 within housing 602 while allowing fluid to enter inlet 611 o rings 618 and 620 provide seals around piston 612 on either end of sleeve 614 a hole 1002 fig1 through sleeve 614 perpendicular to the sleeve 39 s long axis allows fluid to escape through relief path 630 when the incoming fluid pressure forces piston 612 past o ring 618 and sufficiently far to open a path from inlet 611 to escape path 630 like relief passage 430 of the embodiment of fig4 and 5 relief path 630 connects to a fluid reservoir external tank a container or a compressor crankcase not shown so that the fluid is not sprayed out into the environment as happens with prior art rupture.