The usual symptoms of cavitation in a centrifugal pump is （）.

Low compressor head pressure in a refrigeration system can be caused by（）.

The output volume of a positive fixed displacement pump can be changed only by （）.

The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.

An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.

Thermostatic expansion valves can be adjusted for （）.

If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.

An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.

The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.

If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.