Thermostatic expansion valves can be adjusted for （）.

If the head pressure of a reciprocating refrigeration compressor is excessive, （）.

The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.

Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）

When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.

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

Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）

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

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

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