Pump and Flush the Main Bath

To prepare the main bath (MB) for transferring LHe, you must evacuate it so there is no air within, and then ll it with He-4 gas. With the MB over- pressurized with He4 gas, you prevent air from rushing in when you open the exhaust port to enter the LHe transfer stick. Also, we want to make sure the mixture is in the dump so that it stays out of the fridge while the transfer is going on. See proper instructions to pump and flush.