Cryomech CPA289C, Installation And Operation Manual

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Routine Maintenance
8-4
3. Slowly open the service valve.

Do not vent more than 5 psig (0.34 bar) of helium per minute.
4. Close the service valve.
5. Remove the service Aeroquip from the service access port.
8.6 Recharge helium to the helium compressor package
Required tools and equipment:
Quantity Description Comment
1 3/4 in open end wrench For Aeroquip coupling
1 Service Aeroquip coupling For service access port
1 Vacuum/charging system For adding helium
CAUTION
When adding helium to the helium compressor package, the helium must be 99.999% pure.
Contamination of the helium by other gases is a common cause of premature failure and is not
covered by the warranty.
1. Turn the helium compressor package off.
2. Allow the entire system (both the helium compressor package and the cold head)
to come to room temperature.
3. Use helium with a minimum purity of 99.999%.
4. The helium source and regulator must be capable of pressurizing to the desired
pressure.
5. Make sure the service valve is closed.
6. Attach the service Aeroquip coupling to the service access port. See Figure 8-2.
Figure 8-2: Service valve and access port
7. Attach a charging line from the service Aeroquip to a typical vacuum/charging
system as shown in Figure 8-3 and Figure 8-4 below.
Service Aeroquip Coupling
Service Valve
Charging hose