单项选择题
A.refrigerant must be bled off the sensing line before adjustments are made
B.all refrigerant must be pumped into the receiver before adjustments are made
C.time must be allowed for conditions to stabilize in the evaporator before further adjustments are made
D.all refrigerant must be routed through the dehydrator while changing the superheat setting
单项选择题 If a centrifugal pump were continually operated with the discharge valve closed, the （）.
单项选择题 A double suction centrifugal pump impeller has been installed in the reverse direction, and will （）.
单项选择题 Hydraulic machinery failures are commonly caused by misalignment of the system components and by （）.