REFRIGERATION OPERATING ENGINEER LICENSE EXAM QUESTIONS AND
ANSWERS
Oil pressure switch - CORRECT ANSWER✅✅protects the compressor from operating too long with no or
partial lubrication.
Off cycle defrost - CORRECT ANSWER✅✅Used on medium temperature systems for defrost by the air in
the cooler which will be above 32°.
Filter dryer - CORRECT ANSWER✅✅Removes dirt and moisture out of the refrigerator.
Suction accumulator - CORRECT ANSWER✅✅Prevents liquid refrigerant from entering the compressor.
Receiver - CORRECT ANSWER✅✅Stores unused refrigerant in a system that uses a metering device that
varies the refrigerant flow with the load.
Two types of defrost used with low temperature fixtures are _____ and _____. - CORRECT
ANSWER✅✅Hot gas and electric
You must evacuate and punch a hole in a DOT-39 container before disposing of it. - CORRECT
ANSWER✅✅True
By Code, a licensed Refrigeration Operating Engineer cannot break into a freon system in the City of
Seattle. - CORRECT ANSWER✅✅True
High temperature refrigeration is between ___ and ___. - CORRECT ANSWER✅✅45 degrees F and 60
degrees F
Low temperature refrigeration is between ___ and ___. - CORRECT ANSWER✅✅-20 degrees F and 5
degrees F
, Medium temperature refrigeration is between ___ and ___. - CORRECT ANSWER✅✅30 degrees F and
45 degrees F
The average coil to air temperature relationship of the evaporators is ___. - CORRECT ANSWER✅✅15
degrees F differences leaving air and boiling refrigerant temperature.
HCFCs are Hydrochlorofluorocarbins and contain the elements ___. - CORRECT ANSWER✅✅Hydrogen,
chlorine, fluorine.
HFCs are Hydrofluorocargons and contain the elements ___. - CORRECT ANSWER✅✅Hydrogen, fluorine
and carbon.
Ozone Depletion Potential - CORRECT ANSWER✅✅A measurement of CFCs and HCFCs ability to destroy
ozone.
White colored cylinder is used for ___. - CORRECT ANSWER✅✅R-12 refrigerant
Silver colored cylinder is used for ___. - CORRECT ANSWER✅✅R-717 refrigerant
On a gauge manifold the red hose is to be connected to the ___. - CORRECT ANSWER✅✅High side
On a gauge manifold the blue hose is to be connected to the ___. - CORRECT ANSWER✅✅Low side
Boyle's Law - CORRECT ANSWER✅✅Volume of gas varies as pressure varies, but the temperature
remains the same.
Dalton's Law - CORRECT ANSWER✅✅Total pressure of a confined mixture of gasses is the sum of the
pressures of each of the gasses in the mixture.
ANSWERS
Oil pressure switch - CORRECT ANSWER✅✅protects the compressor from operating too long with no or
partial lubrication.
Off cycle defrost - CORRECT ANSWER✅✅Used on medium temperature systems for defrost by the air in
the cooler which will be above 32°.
Filter dryer - CORRECT ANSWER✅✅Removes dirt and moisture out of the refrigerator.
Suction accumulator - CORRECT ANSWER✅✅Prevents liquid refrigerant from entering the compressor.
Receiver - CORRECT ANSWER✅✅Stores unused refrigerant in a system that uses a metering device that
varies the refrigerant flow with the load.
Two types of defrost used with low temperature fixtures are _____ and _____. - CORRECT
ANSWER✅✅Hot gas and electric
You must evacuate and punch a hole in a DOT-39 container before disposing of it. - CORRECT
ANSWER✅✅True
By Code, a licensed Refrigeration Operating Engineer cannot break into a freon system in the City of
Seattle. - CORRECT ANSWER✅✅True
High temperature refrigeration is between ___ and ___. - CORRECT ANSWER✅✅45 degrees F and 60
degrees F
Low temperature refrigeration is between ___ and ___. - CORRECT ANSWER✅✅-20 degrees F and 5
degrees F
, Medium temperature refrigeration is between ___ and ___. - CORRECT ANSWER✅✅30 degrees F and
45 degrees F
The average coil to air temperature relationship of the evaporators is ___. - CORRECT ANSWER✅✅15
degrees F differences leaving air and boiling refrigerant temperature.
HCFCs are Hydrochlorofluorocarbins and contain the elements ___. - CORRECT ANSWER✅✅Hydrogen,
chlorine, fluorine.
HFCs are Hydrofluorocargons and contain the elements ___. - CORRECT ANSWER✅✅Hydrogen, fluorine
and carbon.
Ozone Depletion Potential - CORRECT ANSWER✅✅A measurement of CFCs and HCFCs ability to destroy
ozone.
White colored cylinder is used for ___. - CORRECT ANSWER✅✅R-12 refrigerant
Silver colored cylinder is used for ___. - CORRECT ANSWER✅✅R-717 refrigerant
On a gauge manifold the red hose is to be connected to the ___. - CORRECT ANSWER✅✅High side
On a gauge manifold the blue hose is to be connected to the ___. - CORRECT ANSWER✅✅Low side
Boyle's Law - CORRECT ANSWER✅✅Volume of gas varies as pressure varies, but the temperature
remains the same.
Dalton's Law - CORRECT ANSWER✅✅Total pressure of a confined mixture of gasses is the sum of the
pressures of each of the gasses in the mixture.
