The weighted pressure control is a separate piece. It is put on the vent pipe after the canner is filled, closed and vented. The canner must have a rack to hold jars off the bottom of the canner. On most pressure canners, rubber or rubber-like gaskets keep steam from leaking out around the cover. Replace a worn, stretched or hardened gasket with a new one.
Replacements are available at most local hardware stores or household appliance centers.
You can also order them from the canner manufacturer. If you have further questions, please contact your county office of the NDSU Extension Service.