Refrigerant oil license Questions Chapter 9

The dielectric property of an oil is blank

the amount of moisture in a refrigerant oil, which may be measured by its resistance to the flow of electric current

As the temperature of an oil decreases then what?

the oil's viscosity increases

The flash point of refrigerant oil is blank

the temperature at which oil vapor will flash when exposed to a flame.

Freon-12 is most like methyl chloride because blank.

the vapor densities are the same

Of the following properties of refrigerant system lubricating oil, the one that is a chemical property of the oil is blank

volatility

Floc point is the temperature at which

wax first is noticed separating from the oil

What percentage of oil travels with the refrigerant?

10%

A most desirable quality of Freon refrigerants is blank.

complete miscibility in mineral lube oil

Oil in a refrigeration system should blank

not contain misture

The fire point of a refrigerant oil is the temperature at which blank.

oil will continue to burn

Pour point is the blank.

lowest temperature that oil will flow.

Of the many ways to lubricate a Freon-12 compressor, which of the following is used? Splash, Pump, Chain and loop, or Drop cup

All but Drop cup

How would you determine whether oil is present in other parts of the system?

By using carbon paper at the receiver

The solubility of refirgerant oil is lowest in blank

CO2

Which substance separates from the lubricating oil in an operating evaporator, leaving the oil floating on top of the liquid refrigerant?

CO2

Where should the oil trap be installed on a refrigeration system?

In the discharge line as far from the compressor as possible

Which of the following statements is most correct about the lubrication of a centrifugal compressor ( without regard for the drive) ?

Leakage of refrigerant to the oiling system is common

What causes oil to foam in the compressor crankcase?

Pressure change

Which refrigerant separates from oil in the evaporator?

R22

Which of the following is incorrect? Refrigerant oils have a low flash point and fire point. Refrigerant oils should have a high resistance to the flow of electricity. Refrigerant oils should have a pour point low enough to flow at low temperatures. Or Refrigerant oils should not contain sulphur components

Refrigerant oils have a low flash point and fire point.

In a Freon-12 compressor with a splash scoop lubrication system, what causes the oil to foam?

Sudden drop in crankcase pressure

Which approximates the definition of flash point for refrigerant oils?

The temperature at which an oil vapor will ignite when exposed to flame

What is the purpose of oil in a refrigeration system?

To reduce wear and friction

Viscosity is blank.

coefficient of internal friction

A circulating oil system in a centrifugal compressor system must have at least blank.

a reservoir, a pump, and distribution lines

Which of the following is true? Ammonia does not mix with oil, and floats on top of oil. Carbon dioxide will not mix with oil, and will float on top of oil. Oil flats on top of sulphur dioxide, and the tow do not mix.

all of the above

A refrigerant oil is electronically tested to have a low neutralization number. A low neutralization number indicates blank.

an unstable oil with corrosive acids present

Refrigerating oils in an ammonia plant should blank.

be free of moisture

A desirable property of ammonia refrigerant oil is blank.

being free of water

Indiscriminate use of paraffin-base oil will most seriously affect the blank.

evaporator

Oil foaming in the compressor indicates blank.

high solubility of refrigerant in oil

Carron oil is generally recommended for use in first aid of ammonia burns. It is made of equal parts of linseed oil and blank.

lime water

Carron oil, used for burns, is a mixture of blank.

linseed oil and lime water

In an ammonia compression system, the evaporator becomes oil-logged. The result is blank.

low suction pressure

To add oil to an R-12 reciprocating compressor that has been shut down for this purpose, the oil is blank.

pump into the service valve on the compressor crankcase

An oil system in an R-11 centrifugal system must have blank.

reservoir, pump motor, and distributor lines