Veeco MS40 Operation And Maintenance Manual page 95

Servicing the Purge and Sniff Valves
Vacuum Instrument Corp.
2099 Ninth Avenue
Ronkonkoma, NY 11779
631.737.0900
1109-186-00 Rev. C
6. Coat each O-ring completely with a very thin covering of vacuum
grease (Dow Corning High Vacuum Grease recommended). The
coating should be thin enough so that the grease is barely visible
except for leaving a glossy coat on the O-ring.
7. With a lint-free cloth wipe off any grease or dirt on the O-ring seats.
8. With even pressure replace the O-rings into their respective O-ring
seats. Make sure that each O-ring is securely mounted. Failure to
mount the O-ring properly will cause the valve to malfunction or
fail completely.
9. Re-attach the valve coil and restrictor plate with the two screws
removed in Step 3.
1. Vent the entire system. Follow the procedure stated in Section 4.6.
2. Open the rear panel by turning the captive screw at the top of the
panel 1/4 turn counterclockwise and gently lowering the door.
3. The valves are labeled and mounted on the valve block. Remove
the lower left and upper right screws to access the internal valve
mechanism.
4. While using lint-free gloves, remove the two O-rings, the small
inner O-ring and the larger outer O-ring with a plastic tool. Do not
use metal or any other hard instruments as they may scratch the O-
ring groove. Wipe each O-ring with a lint-free cloth and check each
carefully for nicks, dents or flat spots. Replace when necessary.
5. Coat each O-ring completely with a very thin covering of vacuum
grease (Dow Corning High Vacuum grease recommended). The
coating should be thin enough so that the grease is barely visible
except for leaving a glossy coat on the O-ring.
6. With a lint-free cloth wipe off any grease or dirt on the O-ring seats.
With even pressure replace the O-rings into their respective O-ring
7.
seats. Make sure that each O-ring is securely mounted. Failure to
mount the ring properly will cause the valve to malfunction or fail
completely.
8. Re-attach the valve coil with the two screws removed in Step 3.
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