9861999

Mueller part number 9861999 is the replacement gasket for the 75X plate used in the Accu-Therm AT-75 plate heat exchanger. The compound is EPDM High-Temp, rated to 305°F, and it is supplied in the Clip-In attachment style that the AT-75 plate pack uses - matching the attachment method matters as much as matching the frame, because a glue-in gasket will not seat in a clip-in or Loc-In plate. Compliance is High-Temp Industrial. Gaskets are the wear item in any gasketed plate exchanger and are normally replaced as a full set when a pack is opened for cleaning or when the unit begins weeping at the plate edges. If you are replacing gaskets on a Mueller frame and working from a nameplate rather than a parts list, the plate code 75X is the number to match, not the frame model alone.