Sumitomo F-20L, Operating Manual, Page: 45 / 56

Maintenance
41
Gas Cleanup
Tools required: 2 adapter fittings with valve, 8F Aeroquip, 255919B2.
Open-end wrenches, 1", 1 1/8" and 1 3/16".
Helium gas cylinder with pressure regulator and charge line.
If the equalization pressure shown by the compressor’s pressure gauge is less than 1.4 bar
(20 psig), gas cleanup of the compressor is required. Look for and repair helium leaks. Perform
gas cleanup.
If system components are connected and the equalization pressure of the system is less than
1.4 bar (20 psig), check for leaks. Repair leaks. Perform gas cleanup of the system.
PREVENT EQUIPMENT DAMAGE. Never pull a vacuum on the compressor or
on the cold head. The motors will short circuit if started.
AVOID INJURY.
Disconnect gas lines only when the compressor is stopped.
Disconnecting the cold head while it is cold can create excessively high internal
pressure as the gas warms. Material failure and uncontrolled pressure release
can cause serious injury.
Gas cleanup is required if the compressor’s interior has been opened to the atmosphere or the
equalization pressure is 1.4 bar (20 psig) or lower. Gas cleanup is performed with the
compressor disconnected from the other system components.
NOTE
If the compressor’s interior has been exposed to the atmosphere for an extended
period, gas cleanup may not suffice to guarantee system gas purity. Contact a
Service Center.
1. Disconnect the gas lines from the compressor. Plug the disconnected gas line couplings.
2. Locate two adapter fittings P/N 255919B2. Be sure their valves are closed. Attach them to
the supply and return Aeroquip couplings on the compressor.
3. Connect a charge line to the pressure regulator of a helium gas cylinder containing 99.999%
pure helium gas with a dew point less than -62° C (-80° F) at 20.7 bar (300 psig). Adjust the
gas cylinder pressure regulator to 0.35 bar (5 psig).
4.
While connecting the charge line to the adapter fitting on the compressor’s return coupling,
thoroughly purge the charge line from the regulator. It is important to remove all air
contaminants to prevent them from entering the system.
5. Adjust the pressure regulator to 15.2 bar (220 psig). Open the valve on the adapter fitting
and charge the compressor to 15.2 bar (220 psig).