Veeco MS40 Operation And Maintenance Manual page 92

CAUTION:
Servicing the Vent Valve
CAUTION
Vacuum Instrument Corp.
2099 Ninth Avenue
Ronkonkoma, NY 11779
631.737.0900
1109-186-00 Rev. C
Do not use metal tools or sharp objects to inspect a valve
seat in the valve block. Any scratch will irreparably
damage the seat.
1. Vent the test port.
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. Remove the two wires from the electrical connectors on the valve.
Make note of which wire is connected to each metal prong (yellow
wire to upper prong/striped wire to lower prong).
4. Remove the four screws and washers. Remove the valve coil.
5. Remove the plunger and the seal assembly from the valve coil,
Wipe only the outer area of the seal. Do not remove the seal.
6. The valve's O-ring is in the body of the valve. Remove it with a
plastic or other non-metallic instrument. 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.
7. Wipe the seat on the valve block with a clean, lint free cloth to
remove any contaminants. If necessary, a small amount of alcohol
may be used on the valve block.
Acetone or alcohol is destructive to rubber surfaces such as
the valve's O-ring. When cleaning rubber surfaces use a
clean and dry lint-free cloth.
8. Wipe the O-ring with a clean, lint-free cloth, then coat it with a thin
film of vacuum grease (Dow Corning High Vacuum Grease is
recommended). The coating should be thin enough so that the
grease is barely visible except for leaving a glossy coat on the
rubber. Replace the O-ring in the valve body.
9. Wipe the rubber seal on the end of the valve plunger with a clean,
lint-free cloth. Coat the rubber with a thin film of vacuum grease.
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