Air Conditioning Certification PAST EXAM
QUESTIONS & ANSWERS
Heat which causes a change in temperature of a substance is called; - ✔✔✔sensible heat.
Heat which causes a change in state of a material without a change in temperature is called; -
✔✔✔latent heat.
Heat which is added to a vapor after the change of state occurs is called; - ✔✔✔superheat.
Heat can travel by; - ✔✔✔conduction, convection, radiation.
The movement of heat by way of fluid (or air) is called; - ✔✔✔convection .
The movement of heat by direct contact is called; - ✔✔✔conduction .
The standard unit for measuring the quantity of heat in a substance is; - ✔✔✔the British
Thermal Unit (Btu).
A refrigerat gives up heat when; - ✔✔✔it condenses.
It is desirable for refrigerant in the suction line to be slightly superheated in order to; -
✔✔✔insure liquid refrigerant does not enter the compressor.
The state of refrigerant in the suction line should be; - ✔✔✔low pressure/ low temperature.
The state of the refrigerant entering the condenser is; - ✔✔✔high pressure/ highly superheated
liquid.
The evaporator; - ✔✔✔Transfers heat from the refrigerant to the ambient air.
, Which of the following is NOT a thermodynamic property of refrigerants?
a) Critical point.
b) Saturation point.
c) Enthalpy.
d) Flammability. - ✔✔✔d) Flammability.
The sequential order of steps in the vapor - compression process are; - ✔✔✔compression,
condensation, expansion, vaporization.
If a 30 pound cylinder of reclaimed R-12 refrigerant has been stored over night at 70°F, the pressure
in the cylinder should be approximately; - ✔✔✔70.2 Psig.
Pressures lower than atmospheric are measured in;
a) inches of mercury
b) microns
c) Psig
d) either "A" or "B". - ✔✔✔d) either "A" or "B".
Zero psia (pounds per square inch absolute) is; - ✔✔✔a pressure which cannot be further
reduced.
Zero psig (pounds per square inch guage) is; - ✔✔✔the same as atmospheric pressure.
The temperature at which moisture will start to condense from the air is called; - ✔✔✔dew
point temperature.
A compound pressure guage measures; - ✔✔✔pressure and vacuum.
A mechanical shaft seal is necessary on a; - ✔✔✔open drive compressor.
Liquid slugging is; - ✔✔✔liquid refrigerant in the compressor clearance space.
QUESTIONS & ANSWERS
Heat which causes a change in temperature of a substance is called; - ✔✔✔sensible heat.
Heat which causes a change in state of a material without a change in temperature is called; -
✔✔✔latent heat.
Heat which is added to a vapor after the change of state occurs is called; - ✔✔✔superheat.
Heat can travel by; - ✔✔✔conduction, convection, radiation.
The movement of heat by way of fluid (or air) is called; - ✔✔✔convection .
The movement of heat by direct contact is called; - ✔✔✔conduction .
The standard unit for measuring the quantity of heat in a substance is; - ✔✔✔the British
Thermal Unit (Btu).
A refrigerat gives up heat when; - ✔✔✔it condenses.
It is desirable for refrigerant in the suction line to be slightly superheated in order to; -
✔✔✔insure liquid refrigerant does not enter the compressor.
The state of refrigerant in the suction line should be; - ✔✔✔low pressure/ low temperature.
The state of the refrigerant entering the condenser is; - ✔✔✔high pressure/ highly superheated
liquid.
The evaporator; - ✔✔✔Transfers heat from the refrigerant to the ambient air.
, Which of the following is NOT a thermodynamic property of refrigerants?
a) Critical point.
b) Saturation point.
c) Enthalpy.
d) Flammability. - ✔✔✔d) Flammability.
The sequential order of steps in the vapor - compression process are; - ✔✔✔compression,
condensation, expansion, vaporization.
If a 30 pound cylinder of reclaimed R-12 refrigerant has been stored over night at 70°F, the pressure
in the cylinder should be approximately; - ✔✔✔70.2 Psig.
Pressures lower than atmospheric are measured in;
a) inches of mercury
b) microns
c) Psig
d) either "A" or "B". - ✔✔✔d) either "A" or "B".
Zero psia (pounds per square inch absolute) is; - ✔✔✔a pressure which cannot be further
reduced.
Zero psig (pounds per square inch guage) is; - ✔✔✔the same as atmospheric pressure.
The temperature at which moisture will start to condense from the air is called; - ✔✔✔dew
point temperature.
A compound pressure guage measures; - ✔✔✔pressure and vacuum.
A mechanical shaft seal is necessary on a; - ✔✔✔open drive compressor.
Liquid slugging is; - ✔✔✔liquid refrigerant in the compressor clearance space.
