MKS 640A/641A, Manual, Page: 43 / 88

Down Port Controller Mounting Instructions Chapter Two: Installation
30
5. Tighten the mounting screws with increments of approximately
1
/
8
turn each, using a
5
/
32
inch hex driver. Do not make a “criss-cross” pattern; instead close the fitting to substrate
gap about halfway on one fitting then on the other. Finish the seal on the first fitting
followed by the second.
Tighten the screws so that the seal is evenly tightened and the controller is not twisted.
Caution
Tighten the screws so that the seal is evenly tightened and the
controller is not twisted. Incorrectly tightening the screws may
damage the seal.
6. Apply the final seating torque appropriate to the fastener selected for the assembly.
The fitting and keeper should be uniformly “bottomed” against the substrate.
Caution
The fastener material, plating, lubrication, and size define the torque
limitations that should be applied to the screw. Refer to the screw
manufacturer’s literature for the proper torque levels.