cr_c1 and cr_12 are both at about 45K and heading slowly down, so the 
gamble of going to // cold return worked. Maximum opening of CV155 is 
limited by CV204 goes fully closed and suction pressure begins to rise 
above set point. Adjust cv155 to keep cv204 just at the closed point. Keep 
tweaking cv155 and turbine speeds as things get cooler.