#5 give a good answer. ; U: n' q% {2 A* b+ w0 O1 J$ ] e! _5 W- Q" O
cause different pressure areas , we can just apply a small pressure to enable the poppet out , u4 P/ B8 p; r6 G
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it should be a two stage valve. a little bit complex kind. once you get its working function. then it is easy for. u