...
- Set the regulator on the helium tank to 210 psig.
- Open the Hoke valve (the black knob) to pressurize the coldhead and maintenance manifold to ~200 psig.
- Close the Hoke valve.
- Open the ball valve (handle) to depressurize the manifold to 30-50 psig. Don't go below 30 psig.
- Repeat at least 10 times. The manual says 25.
- The manual also says that for every 5th flush, run the coldhead for 10-30 seconds. This would be done by switching on the compressor even though the helium lines are not attached to the coldhead. This makes me nervous and I am content with 10-12 simple flushes of the manifoldstep is done with the coldhead pressurized to 200 psig.
- Finally, pressurize the coldhead back to 200 psig.
- Close the helium regulator.
- Disconnect the helium hoses from the manifold.
- Return the coldhead to its normal operating setup.
The cooldown can be started in if IGRINS has been on the vacuum pump for at least 2 hours.