Ac Certification FORECASTED EXAM
QUESTIONS & ANSWERS
Heat which can cause a change in temperature of a substance is called; - ✔✔✔Sensible Heat
Heat added to a substance without a rise in temperature;(example: liquid refrigerant to gas) this
process is called? - ✔✔✔Latent Heat of Vaporization
Heat added to the refrigerant in a vapor state after the evaporation process is called; -
✔✔✔Superheat
A scroll compressor move refrigerant by means of; - ✔✔✔Involute spirals
The movement of heat by way of fluid(of air) is called; - ✔✔✔Convection
The movement of heat through a solid object is called; - ✔✔✔Conduction
The standard unit for measuring the quantity of heat in a substance is; - ✔✔✔The British
Thermal Unit(Btu)
A refrigerant gives up heat when; - ✔✔✔it Condenses
Why must refrigerant in the suction line be slightly warmer than the saturation temperature? -
✔✔✔Prevent liquid slugging of the compressor
The state of the refrigerant entering the condenser is; - ✔✔✔High pressure/highly superheated
vapor
The evaporator; - ✔✔✔Transfers heat from the refrigerated space to the refrigerant
Which of the following is NOT a thermodynamic property of refrigerants? - ✔✔✔Flammability
, The state of the refrigerant in the suction line should be; - ✔✔✔Low pressure/low temperature
liquid
The sequential order of steps in the vapor-compression process are; -
✔✔✔compression,condensation, expansion, vaporization
If a 30 pound cylinder of reclaimed R-410A refrigerant has been stored overnight at 70F, the
pressure ain the cylinder should be approximately; - ✔✔✔201psig
Fan airflow pressures are usually measured in; - ✔✔✔Inches of water column(WC)
Zero psia(pounds per square inch absolute) is; - ✔✔✔A pressure which cannot be further
reduced
Zero psig(pounds per square inch gauge)is; - ✔✔✔The same as atmospheric pressure
The temperature at which moisture will start to condensate from the air is called; - ✔✔✔Dew
point temperature
A compound pressure and gauge measures; - ✔✔✔Pressure and vaccum
A mechanical shaft seal is necessary on a; - ✔✔✔Open drive compressor
Liquid slugging is; - ✔✔✔Liquid refrigerant in the compressor clearance space
The clearance space in a reciprocating compressor - ✔✔✔Has an effect on compressor capacity
Which of the following types of air conditioning compressors is most energy efficient? -
✔✔✔Scroll
Which of the following represents the right order for the functions of a condenser? - ✔✔✔De-
Superheat, Condenses, Sub-Cools
QUESTIONS & ANSWERS
Heat which can cause a change in temperature of a substance is called; - ✔✔✔Sensible Heat
Heat added to a substance without a rise in temperature;(example: liquid refrigerant to gas) this
process is called? - ✔✔✔Latent Heat of Vaporization
Heat added to the refrigerant in a vapor state after the evaporation process is called; -
✔✔✔Superheat
A scroll compressor move refrigerant by means of; - ✔✔✔Involute spirals
The movement of heat by way of fluid(of air) is called; - ✔✔✔Convection
The movement of heat through a solid object is called; - ✔✔✔Conduction
The standard unit for measuring the quantity of heat in a substance is; - ✔✔✔The British
Thermal Unit(Btu)
A refrigerant gives up heat when; - ✔✔✔it Condenses
Why must refrigerant in the suction line be slightly warmer than the saturation temperature? -
✔✔✔Prevent liquid slugging of the compressor
The state of the refrigerant entering the condenser is; - ✔✔✔High pressure/highly superheated
vapor
The evaporator; - ✔✔✔Transfers heat from the refrigerated space to the refrigerant
Which of the following is NOT a thermodynamic property of refrigerants? - ✔✔✔Flammability
, The state of the refrigerant in the suction line should be; - ✔✔✔Low pressure/low temperature
liquid
The sequential order of steps in the vapor-compression process are; -
✔✔✔compression,condensation, expansion, vaporization
If a 30 pound cylinder of reclaimed R-410A refrigerant has been stored overnight at 70F, the
pressure ain the cylinder should be approximately; - ✔✔✔201psig
Fan airflow pressures are usually measured in; - ✔✔✔Inches of water column(WC)
Zero psia(pounds per square inch absolute) is; - ✔✔✔A pressure which cannot be further
reduced
Zero psig(pounds per square inch gauge)is; - ✔✔✔The same as atmospheric pressure
The temperature at which moisture will start to condensate from the air is called; - ✔✔✔Dew
point temperature
A compound pressure and gauge measures; - ✔✔✔Pressure and vaccum
A mechanical shaft seal is necessary on a; - ✔✔✔Open drive compressor
Liquid slugging is; - ✔✔✔Liquid refrigerant in the compressor clearance space
The clearance space in a reciprocating compressor - ✔✔✔Has an effect on compressor capacity
Which of the following types of air conditioning compressors is most energy efficient? -
✔✔✔Scroll
Which of the following represents the right order for the functions of a condenser? - ✔✔✔De-
Superheat, Condenses, Sub-Cools
