MKS 640A/641A, Manual, Page: 38 / 88

Chapter Two: Installation Down Port Controller Mounting Instructions
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9. Place the controller and seal assembly onto the substrate; make sure to align the seals and
screws properly.
10. Finger-tighten the screws evenly. Ensure that the controller is level or parallel to the
substrate.
11. Use a hex driver to tighten the mounting screws with increments of approximately
1
/
8
turn each. 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.
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.
12. Apply the final seating torque appropriate to the fastener used.
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.
13. Inspect the assembly to ensure that the controller is uniformly bottomed against the
substrate and the retainer is tightly clamped.