water / fuel lever on van chassis
 

hello folks , I've got a '97 E-350 7.3 di turbo van , It didn't come with the owners manual so my question is , next to the oil and trans dip sticks , there is a handle that says fuel/water , do I pull the handle to empty the fuel box or is it a twist deal , and how far ? I love the van and don't want to break it for lack of asking a simple question.