WITH ANSWERS 2025/2026.
Conduction is defined as heat energy that is - ANSWERSmoving through a solid
substance
What is the primary purpose of a refrigeration system ? - ANSWERSachieve and
maintain a temperature
What is a hazard of trapping liquid ? - ANSWERSA possible release
How much can the pressure of trapped liquid increase per degree Fahrenheit of
temperature increase - ANSWERS100 to 150 psi
Mechanical refrigeration is a series of steps that - ANSWERSmoves heat energy from a
space or object to an area where it can do no harm
How does the refrigeration compressor maintain the temperature in the system
evaporators ? - ANSWERSDrawing out vaporized refrigerant at a rate to maintain the
desired evaporating pressure
Which natural refrigerant is considered to be non- flammable - ANSWERSCarbon
Dioxide
Heat energy always flows - ANSWERSfrom an object at a higher temperature to an
object at a lower temperature
32 psia equals - ANSWERS17.3 psig
0 ° F is equal to - ANSWERS-18 ° C
Why does the refrigerant in the condenser change state from vapor to liquid -
ANSWERSThe refrigerant loses heat energy to the surrounding environment
If a liquid is below its saturation temperature what is its condition ? -
ANSWERSSubcooled
What are the four necessary components of a mechanical refrigeration system ? -
ANSWERSexpansion device , evaporator , compressor , condenser
Superheat is found at which points of a typical system ? - ANSWERSThe compressor
suction and compressor discharge line
, What are the replacement blended refrigerants called ? - ANSWERSAn azeotrope or
zeotrope
What is one positive characteristic of halocarbon refrigerants ? - ANSWERSThey are
usually not flammable
What is the primary reason for concern about HCFC- 22 concentration in an engine
room ? - ANSWERSOxygen deprivation
O psig is equal to - ANSWERS14.7 psia
Discharge vapor from all compressors - ANSWERSwill contain some level of superheat
Which category of compressor " traps " a volume of refrigerant vapor prior to
compression ? - ANSWERSPositive displacement
When suction pressure rises , the operator should - ANSWERSstart another
compressor
The crankcase oil heater should be ON - ANSWERSwhen the compressor is off .
Slugging is caused by - ANSWERSoil or liquid refrigerant
What should be done if liquid refrigerant appears while draining oil ? - ANSWERSDo
what the SOP states
Proper oil management for a refrigeration system requires that - ANSWERSa log should
record all oil added to and removed from a system
When heat is added to saturated liquid refrigerant it will always - ANSWERSevaporate
What effect does the addition of fins to evaporator coils have ? - ANSWERSIt increases
the efficiency of a unit by increasing the surface area
During hot gas defrost - ANSWERShigh pressure gas flows through and condenses in
the evaporator
Evaporative condensers - ANSWERSderive their heat rejection capability from the
evaporation of water
Air cooled condensers usually have - ANSWERShigher head pressures than
evaporative condensers
What are the two types high pressure receivers based on how liquid flows into them ? -
ANSWERSSurge and through type