When the sequencer is ENABLED, the operation is as follows. When the LN2 level falls below MIN, the CoolDown Valve opens, permitting nitrogen to flow through the hose. This precools the hose, as came be seen by monitoring a silicon diode thermometer, TD91110, installed near the junction between the two valves. When the Set pt. temperature is achieved, the CoolDown valve closes and the Fill Valve opens. When the MAX LN2 level is reached, the Fill Valve closes. The current status of the LN2 sequencer is displayed at the top of the control screen.
The LN2 jacket can be filled at any time by operating the CoolDown and Fill solenoids manually.