Operation
7-1
Section 7: Operation
7.1 Starting the system
7.1.1 Checks before operating
1) Check the system pressure - the gauges should read the pressure specified in
Appendix A.
o If the pressure is too high, vent some of the helium following the instructions in
Section 6.
o If the pressure is too low, add helium following the instructions in Section 8.
2) Make sure the cold head motor cord is connected to both the compressor and the
cold head.
3) Make sure the instrumentation cord is connected to both the Re-liquefier and the
pressure controller.
4) Make sure all Aeroquip couplings are securely fastened and the helium flex lines
are oriented correctly.
5) Make sure the input power meets the specifications on the identification label.
CAUTION
A voltage deviation of more than 10% above or below the voltage rating can cause
compressor motor overheating and possible failure. Indications of voltage operation
outside that range will void the compressor warranty.
6) Make sure the flow rate and temperature range of the cooling water meet the
requirements specified in Section 5.
7) Check that the dedicated circuit breaker is on.
CAUTION
Operating the helium reliquefier in a magnetic field of greater than 500 gauss will void
the warranty.
7.1.2 Startup procedure
1) Set the Pressure Controller
a. If your cryostat boil off rate is smaller than the liquefaction rate of the re-
liquefier, it is necessary to apply heat to the Pulse Tube condensing heat
exchanger. This will ensure that the system pressure remains above
atmospheric pressure. Cryomech recommends that you leave the
pressure setpoint at 3psig. Please read the attached HRC-110 pressure
controller manual for instructions on how to change this set point, if
desired. The pressure controller heater output ships disabled. Enter the
main menu and enable the heater output for pressure control
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