2000 MS Hardware Maintenance
96
Mass Spectrometer Maintenance
CAUTION
Be careful not to scratch or damage sealing surfaces.
21. Pour the diffusion pump fluid (03-930639-01) through one of the holes in the
diffusion pump’s inlet baffle. Part Number 03-930639-01 contains 40 cm
3
. This
is a full charge, plus an allowance for fluid that remains on the walls of the
container.
NOTE: The fluid is highly viscous and takes five minutes for a full charge to
reach the reservoir and show in the sight glass.
22. Add fluid until the level is midway in the “Full Cold” zone.
23. Wipe any spillage from the inlet baffle using a clean lint free cloth.
24. Refit the diffusion pump.
Changing the Diffusion Pump Heater
The cartridge heater is factory coated with an anti-seize lubricant to facilitate
easy removal of the heater. To change the diffusion pump heater:
1. Remove
the
pump.
2. Turn the pump upside down and drain the fluid into a suitable container.
Hazardous chemicals may be present. Avoid contact with skin. Use proper
eye and skin protection.
WARNING
Toxic residues from mass spectrometer samples will build up in used pump
fluid. Dispose of all used pump fluid in accordance with applicable regulations.
Place a hazards warning label on the container, if appropriate.
3. Remove the two screws holding the over temperature switch in position.
4. Remove the two retaining screws and the base plate.
5. Use an 11/32 socket to unscrew the two nuts.
6. Remove the ground wire, harness clamp, retaining plate and insulating pad.
7. Pull the heater out by its leads, twisting if necessary.
8. If the heater does not come out:
a. Apply penetrating oil around the cartridge heater and let it stand for 10
minutes.
b. Drive a ¼ inch wide flat blade screwdriver approximately 1/8 deep into
the center of the heater between the electrical leads.
c. Gently turn the screwdriver to break the heater free.
d. Pull the heater out by its leads, twisting if necessary.
