An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.

A salinity indicator is used to determine the （）.

Thermostatic expansion valves can be adjusted for （）.

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

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

A grease gun is generally used to lubricate a （）.

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

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

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

Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.