Tx HVAC Technician Certification TestBank
Heat which causes a change in temperature of a substance is called -correct answers-
sensible heat,
Heat added to a substance without a rise in temperature; (example: liquid refrigerant to gas)
this process la called? -correct answers-latent heat
Heat added to the refrigerant in vapor state after the evaporation process is called, -correct
answers-superheat
A scroll compressor moves refrigerant by means of; -correct answers-involute spirals
The movement of heat by way of fluid or is called; air -correct answers-convection
The movement of heat through a solid object is called; -correct answers-radiation
The standard unit for measuring the quantity of heat in a substance is -correct answers-
British Thermal Unit
A refrigerant gives up heat when it; -correct answers-it condenses
Why must refrigerant in the suction line be slightly warmer than the saturation
temperature? -correct answers-prevent liquid slugging of the compressor.
It is desirable for refrigerant in the suction line to be slightly superheated in order to; -
correct answers-insure liquid refrigerant does not enter the compressor.,
The state of the refrigerant in the suction line should be -correct answers-low pressure/ low
temperature vapor
The state of the refrigerant entering the condenser is -correct answers-High Pressure/ Highly
Superheated Vapor
The Evaporator -correct answers-Transfers heat from the refrigerated space to the
refrigerant
The Evaporator -correct answers-Transfers heat from the refrigerated space to the
refrigerant
Which of the following is not a Thermodynamic Property of refrigerant -correct answers-
Flammability
The sequential order of steps in the vapor-compression process are: -correct answers-
Compression, Condensation, Expansion, Vaporization
If a 30 lb container of $-410A refrigerant has been stored over night at 70 degrees F, the
pressure in the cylinder should be approximately -correct answers-201 Degrees Faranheit
Fan Airflow pressures are usually measured in -correct answers-Inches of water column
, Zero Psia (pounds per square inch absolute) is -correct answers-a pressure which cannot be
further reduced
Zero Psig (pounds per square inch gauge) -correct answers-The same as atmospheric
pressure
The Temperature at which moisture will start to condense from the air is called -correct
answers-Dew Point Temperature
A Compound pressure gauge measures -correct answers-Pressure and Vacuum
A Mechanical shaft seal is necesssary on a -correct answers-Open drive compressor
Liquid slugging is -correct answers-Liquid refrigerant in the compressor clearance space
The Clearance space in a reciprocating compressor -correct answers-has an effect on
compressor capacity
Which of the following types of air conditioning compressors is more efficient -correct
answers-Centrifugal
Which of the following represnet the right order for the functionsof a condenser -correct
answers-De-Superheats, Condenses, and Sub-cools
Refrigerant R-134a vapor enters the condenser at 124psig, 100 degrees faranheit, It leaves
as a liquid from the condenser, sub-cooled 20 degrees faranheit, and the pressure will be
approximately -correct answers-124 psig
There are 3 basic types of condensers, air cooled, water cooled, and -correct answers-
evaporative cooled
10 lbs of refrigerant passing through a water cooled condenser will lose 20 BTU of heat/
pound. If 10#'s of water passes through the condenser with an entering temp of 80 degrees,
the temp of the water leaving the condenser is -correct answers-100 degrees faranheit
The heat removed from the refrigerant by the condenser is -correct answers-both sensible
and latent heat
An energy recovery ventilator is -correct answers-an air to air heat exhanger to recover heat
Which of hte following can not be used as a low ambient temperature control? -correct
answers-Crankcase regulating valves
When testing the efficiency of an air cooled condenser, the refrigerant condensing
temperature should be no more than _____ higher than the entering air temp. -correct
answers-30 degrees
The First function a condenser must perform is to ___ the refrigerant before condesing can
occur. -correct answers-De-Superheat
Heat which causes a change in temperature of a substance is called -correct answers-
sensible heat,
Heat added to a substance without a rise in temperature; (example: liquid refrigerant to gas)
this process la called? -correct answers-latent heat
Heat added to the refrigerant in vapor state after the evaporation process is called, -correct
answers-superheat
A scroll compressor moves refrigerant by means of; -correct answers-involute spirals
The movement of heat by way of fluid or is called; air -correct answers-convection
The movement of heat through a solid object is called; -correct answers-radiation
The standard unit for measuring the quantity of heat in a substance is -correct answers-
British Thermal Unit
A refrigerant gives up heat when it; -correct answers-it condenses
Why must refrigerant in the suction line be slightly warmer than the saturation
temperature? -correct answers-prevent liquid slugging of the compressor.
It is desirable for refrigerant in the suction line to be slightly superheated in order to; -
correct answers-insure liquid refrigerant does not enter the compressor.,
The state of the refrigerant in the suction line should be -correct answers-low pressure/ low
temperature vapor
The state of the refrigerant entering the condenser is -correct answers-High Pressure/ Highly
Superheated Vapor
The Evaporator -correct answers-Transfers heat from the refrigerated space to the
refrigerant
The Evaporator -correct answers-Transfers heat from the refrigerated space to the
refrigerant
Which of the following is not a Thermodynamic Property of refrigerant -correct answers-
Flammability
The sequential order of steps in the vapor-compression process are: -correct answers-
Compression, Condensation, Expansion, Vaporization
If a 30 lb container of $-410A refrigerant has been stored over night at 70 degrees F, the
pressure in the cylinder should be approximately -correct answers-201 Degrees Faranheit
Fan Airflow pressures are usually measured in -correct answers-Inches of water column
, Zero Psia (pounds per square inch absolute) is -correct answers-a pressure which cannot be
further reduced
Zero Psig (pounds per square inch gauge) -correct answers-The same as atmospheric
pressure
The Temperature at which moisture will start to condense from the air is called -correct
answers-Dew Point Temperature
A Compound pressure gauge measures -correct answers-Pressure and Vacuum
A Mechanical shaft seal is necesssary on a -correct answers-Open drive compressor
Liquid slugging is -correct answers-Liquid refrigerant in the compressor clearance space
The Clearance space in a reciprocating compressor -correct answers-has an effect on
compressor capacity
Which of the following types of air conditioning compressors is more efficient -correct
answers-Centrifugal
Which of the following represnet the right order for the functionsof a condenser -correct
answers-De-Superheats, Condenses, and Sub-cools
Refrigerant R-134a vapor enters the condenser at 124psig, 100 degrees faranheit, It leaves
as a liquid from the condenser, sub-cooled 20 degrees faranheit, and the pressure will be
approximately -correct answers-124 psig
There are 3 basic types of condensers, air cooled, water cooled, and -correct answers-
evaporative cooled
10 lbs of refrigerant passing through a water cooled condenser will lose 20 BTU of heat/
pound. If 10#'s of water passes through the condenser with an entering temp of 80 degrees,
the temp of the water leaving the condenser is -correct answers-100 degrees faranheit
The heat removed from the refrigerant by the condenser is -correct answers-both sensible
and latent heat
An energy recovery ventilator is -correct answers-an air to air heat exhanger to recover heat
Which of hte following can not be used as a low ambient temperature control? -correct
answers-Crankcase regulating valves
When testing the efficiency of an air cooled condenser, the refrigerant condensing
temperature should be no more than _____ higher than the entering air temp. -correct
answers-30 degrees
The First function a condenser must perform is to ___ the refrigerant before condesing can
occur. -correct answers-De-Superheat
