When the fridge is in Hold Cold Mode, it means we have a liquid in the fridge nose and holding target material. In that case, we must keep the target material to preserve the paramagnetic centers. In the Hold Cold Mode, you will see the fridge parameters as follows:
We fill the fridge to Heat-Ex Top for the Cold Hold Mode and close the Run and Bypass valves. To reduce LHe consumption in the fridge nose, set the GV bypass pressure on PID at 100 torr and Set the Separator flow at 20slm.
Keep monitoring the target parameters, say Nose LHe Level (%), when it comes to 50% then start filling the filling and replenish the level at Heat-Ex bottom.
Please follow this page to put the fridge in the Cold Hold Mode: Cryo-control parameters / conditions when the fridge is in Hold Cold Mode - Wiki Post Portal - Confluence (virginia.edu)