Unit 8

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

• in a vacuum

• open to the atmosphere

• operating with all fans activated

• standing with dry nitrogen pressure of 150 psig in the system

When moisture is present in a refrigeration system, it will react with the refrigerant and the oil to form ____.

• acid
• carbon dioxide

• carbon monoxide

• carbolic acid

Non-condensable gases ____.

• are desirable in a refrigeration system

• are undesirable in a refrigeration system

• condense readily under normal atmospheric conditions

• help in pulling a vacuum

To pull a vacuum means to ____.

• lower the pressure in a refrigeration system below atmospheric

• raise the pressure in a refrigeration system

• allow refrigerant to escape into the atmosphere

• condense the gas in the system

A compound gauge ____.

• indicates pressures above 14.696 psia

• indicates pressures in inches Hg below atmospheric pressure

• is one of two gauges on a typical gauge manifold

• All of the above.

A micron gauge is used to measure ____.

• atmospheric pressures at high altitudes

• atmospheric pressures at sea level

• absolute pressures below 1 mm Hg

• high pressure in a refrigeration system

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

• 200 to 100 microns.

• 500 to 200 microns.

• 300 to 200 microns.

• 500 to 300 microns.

Which of the following represents the lowest vacuum?

• 10 psia.

• 5 in. Hg vacuum.

• 5 psig.

• 1000 microns.

A multiple evacuation means that ____.

• you connect three vacuum pumps simultaneously to a refrigeration system and pull a vacuum

• you pull a vacuum on three different systems at the same time

• you pull a vacuum on a refrigeration system more than once, allowing refrigerant or nitrogen into the system between each procedure

• there must be more than one system operating before a vacuum can be pulled

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

• vaporized

• condensed

• cooled

• solidified