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
