Exam 8: Leak Detection, System Evacuation and System Clean-Up

Clearance tolerances are such that the ordinary clean refrigerant oil can be used satisfactorily in a vacuum pump.

To insure accurate testing, the best material to use for connecting lines to the vacuum pump and gauge set is ____.

After repairing a system that has had an electrical motor failure (compressor burnout), it is good field practice to re-use the recovered refrigerant in that system.

When using a "standing pressure test" for leak-checking, ____________________ should never be used since an explosive mixture can be created.

Which of the following represents the lowest vacuum?

A pressure of 100 microns has been reached with the vacuum pump operating. The pump is turned off and the gauge reading rises to 5,000 microns and stays there. What does this indicate?

A(n) ____________________ pressure could also mean refrigerant vapor is still seeping from the refrigeration system.

A multiple evacuation means that ____.

Moisture in a liquid state must be ____ before it can be removed with a vacuum pump.

The oil in a vacuum pump should be changed after each time it is used.

The maximum recommended pressure for leak testing is 150 psig on the low-pressure side of the system.

A pressure of 100 microns has been reached with the vacuum pump operating. The pump is turned off and the gauge reading rises to 500 microns and stays there. What does this indicate?

At what pressure range does the technician valve off the vacuum pump when evacuating to a deep vacuum?

A pressure of 100 microns has been reached with the vacuum pump operating. The pump is turned off and the gauge reading rises above 5,000 microns and keeps rising. What does this indicate?

The electronic vacuum gage is attached to the system so it can measure the pressure ____________________ the system.

Why is refrigerant not used for a system standing pressure test?

The best method of leak checking is when the refrigeration system is ____.

Air entering a refrigerant system can eventually lead to compressor failure.

Only two substances should be in the refrigeration system for proper operation. They are ____________________ and oil.

There are ____________________ microns in 1 mm Hg.