Routine Maintenance
8-3
8.5 Vent excess helium
Required tools:
Quantity Description Comment
1 3/4” Open end wrench
For Aeroquip coupling
1
Service Aeroquip coupling
For service access port
CAUTION
Venting more than 5 PSIG (.34 bar / 34 kilopascal) of helium per minute will lead to
improper oil migration within the system. If this condition occurs, factory service will
be required.
This procedure should only be used to vent small quantities of helium from an
overcharged system.
1) Make sure the service valve is closed. See Figure 8-2.
2) Attach the small service Aeroquip coupling to the service access port.
3) Open the service valve slowly. Do not vent more than 5 PSIG (.34 bar / 34 kilopascal)
of helium per minute.
4) After venting the helium, close the service valve and remove the service Aeroquip
from the service access port.
8.6 Recharge helium
Required tools and equipment:
Quantity Description Comment
1 3/4” Open end wrench
For Aeroquip coupling
1
Service Aeroquip coupling
For service access port
1 Vacuum/charging station For adding helium
CAUTION
When adding helium, the helium must be 99.999% pure. Contamination by other
gases will result in the freezing of the contaminant gases in the cold head because
their freezing temperature is much higher than that of helium. Contaminants in the
helium charge will severely degrade the cold head's function and it will require factory
servicing.
Contamination of the helium by other gases is a common cause of premature failure
and, unless resulting from a system failure, is not covered by the warranty.
This procedure should be performed with the compressor package shut down. Adding
helium is possible whether or not the cold head is attached to the compressor package.
Both the service access and service valve are connected to the low-pressure manifold of
the compressor.
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