Commercial refrigeration MAIN
EXAM QUESTIONS WITH CORRECT
SOLUTIONS||UPDATED 2026/2027
SYLLABUS||A+ GRADED||<<NEWEST
VERSION>>
Which type of system reduces total amount of refrigerant charge required? -
ANSWER ✓ Secondary loop
The components for a self contained system - ANSWER ✓ Are selected and
assembled by the equipment manufacturer
The normal fluid temperature drop through a glycol coil on a secondary cooling
loop is - ANSWER ✓ 10 degrees
Compare the installation cost of multiple cases with a separate condensing unit for
each refrigerated case versus a rack system - ANSWER ✓ The rack system
generally will have a lower installed cost
What is an uneven rack system? - ANSWER ✓ A rack that has different capacity
compressors
Defrost on a low temperature case is normally accomplished - ANSWER ✓ By
shutting off the compressor and energizing electric defrost heaters
If the evaporator in a reach in freezer is coated with a large quantity of ice -
ANSWER ✓ It operates less efficiently because the ice acts as an insulation
Along with the refrigerant that is being discharged, reciprocating and rotary
compressors will discharge which of the following as it leaves the compressor? -
ANSWER ✓ Oil
, Which of the following are used to separate and collect some of the oil in the
discharge line as it leaves the compressor and then return it to the compressor's
crankcase? - ANSWER ✓ Oil separtors
Which of the following type of valve is not considered an isolation valve? -
ANSWER ✓ Solenoid valves
The advantage of ball valves over other types of manual refrigeration valve is that
they? - ANSWER ✓ Offer less resistance to flow
In most commercial refrigeration systems, most of the excess refrigerant that is
not being used is stored in? - ANSWER ✓ The liquid receiver
Moisture indicators are normally part of? - ANSWER ✓ A sightglass
One method of elevating system liquid pressure is to? - ANSWER ✓ Control the
operation of the condenser fan motor
Using heat-reclaim coils will help improve a building's overall? - ANSWER ✓
Heat Efficiency
What does an evaporator pressure regulator do? - ANSWER ✓ It will not allow in
the evaporator pressure to drop below its setpoint, even if the suction pressure is
lower
What types of systems use evaporator pressure regulators (EPR)? - ANSWER ✓
System with multiple evaporators
A flow control device that stops or allows the flow of a refrigerant in a
refrigeration system based on an electric signal in? - ANSWER ✓ A solenoid valve
A suction-to-liquid line heat exchanger? - ANSWER ✓ Increases both superheat
and subcooling
Why is it necessary to have controls for maintaining a minimum high side
pressure on outdoor aircooled condensers? - ANSWER ✓ Refrigeration metering
devices require a minimum pressure drop to operate
, When installing a solenoid valve? - ANSWER ✓ The arrow stamped on the body
should point in the direction of flow
Where in the system is an oil separator installed? - ANSWER ✓ In the discharge
line leaving the compressor
Which refrigeration device would most likely be installed in the discharge line
leaving the compressor to prevent liquid refrigerant from draining from a raised
condenser into the compressor head? - ANSWER ✓ A check valve
Why is the filter drier important? - ANSWER ✓ It keeps the system clean and dry
Why are liquid line filter-driers required for all systems using HFC refrigerant? -
ANSWER ✓ Because the POE oil used with HFC refrigerant is very hygroscopic
What is the material inside the filter-drier called? - ANSWER ✓ Dessicant
How can a technician determine when a filter-drier is stopped up and needs
changing? - ANSWER ✓ The pressure drop will exceed 2 psig
How does increased store humidity affect the operation of the refrigerated cases? -
ANSWER ✓ Operating time increases and efficiency decreases due to increased
coil frosting
Open display cases are designed - ANSWER ✓ To keep product at the same
temperature it went in
How is smoke candle used when troubleshooting an open display case? -
ANSWER ✓ It shows air curtain pattern
In which system is both the sensible heat and latent heat recovered from the
refrigerant? - ANSWER ✓ Parallel
What is the primary design challenge for CO2 refrigeration systems? - ANSWER
✓ The high operating pressures of CO2 refrigerant
The airflow on a single deck coffin style open display case - ANSWER ✓ Is all
around the product
EXAM QUESTIONS WITH CORRECT
SOLUTIONS||UPDATED 2026/2027
SYLLABUS||A+ GRADED||<<NEWEST
VERSION>>
Which type of system reduces total amount of refrigerant charge required? -
ANSWER ✓ Secondary loop
The components for a self contained system - ANSWER ✓ Are selected and
assembled by the equipment manufacturer
The normal fluid temperature drop through a glycol coil on a secondary cooling
loop is - ANSWER ✓ 10 degrees
Compare the installation cost of multiple cases with a separate condensing unit for
each refrigerated case versus a rack system - ANSWER ✓ The rack system
generally will have a lower installed cost
What is an uneven rack system? - ANSWER ✓ A rack that has different capacity
compressors
Defrost on a low temperature case is normally accomplished - ANSWER ✓ By
shutting off the compressor and energizing electric defrost heaters
If the evaporator in a reach in freezer is coated with a large quantity of ice -
ANSWER ✓ It operates less efficiently because the ice acts as an insulation
Along with the refrigerant that is being discharged, reciprocating and rotary
compressors will discharge which of the following as it leaves the compressor? -
ANSWER ✓ Oil
, Which of the following are used to separate and collect some of the oil in the
discharge line as it leaves the compressor and then return it to the compressor's
crankcase? - ANSWER ✓ Oil separtors
Which of the following type of valve is not considered an isolation valve? -
ANSWER ✓ Solenoid valves
The advantage of ball valves over other types of manual refrigeration valve is that
they? - ANSWER ✓ Offer less resistance to flow
In most commercial refrigeration systems, most of the excess refrigerant that is
not being used is stored in? - ANSWER ✓ The liquid receiver
Moisture indicators are normally part of? - ANSWER ✓ A sightglass
One method of elevating system liquid pressure is to? - ANSWER ✓ Control the
operation of the condenser fan motor
Using heat-reclaim coils will help improve a building's overall? - ANSWER ✓
Heat Efficiency
What does an evaporator pressure regulator do? - ANSWER ✓ It will not allow in
the evaporator pressure to drop below its setpoint, even if the suction pressure is
lower
What types of systems use evaporator pressure regulators (EPR)? - ANSWER ✓
System with multiple evaporators
A flow control device that stops or allows the flow of a refrigerant in a
refrigeration system based on an electric signal in? - ANSWER ✓ A solenoid valve
A suction-to-liquid line heat exchanger? - ANSWER ✓ Increases both superheat
and subcooling
Why is it necessary to have controls for maintaining a minimum high side
pressure on outdoor aircooled condensers? - ANSWER ✓ Refrigeration metering
devices require a minimum pressure drop to operate
, When installing a solenoid valve? - ANSWER ✓ The arrow stamped on the body
should point in the direction of flow
Where in the system is an oil separator installed? - ANSWER ✓ In the discharge
line leaving the compressor
Which refrigeration device would most likely be installed in the discharge line
leaving the compressor to prevent liquid refrigerant from draining from a raised
condenser into the compressor head? - ANSWER ✓ A check valve
Why is the filter drier important? - ANSWER ✓ It keeps the system clean and dry
Why are liquid line filter-driers required for all systems using HFC refrigerant? -
ANSWER ✓ Because the POE oil used with HFC refrigerant is very hygroscopic
What is the material inside the filter-drier called? - ANSWER ✓ Dessicant
How can a technician determine when a filter-drier is stopped up and needs
changing? - ANSWER ✓ The pressure drop will exceed 2 psig
How does increased store humidity affect the operation of the refrigerated cases? -
ANSWER ✓ Operating time increases and efficiency decreases due to increased
coil frosting
Open display cases are designed - ANSWER ✓ To keep product at the same
temperature it went in
How is smoke candle used when troubleshooting an open display case? -
ANSWER ✓ It shows air curtain pattern
In which system is both the sensible heat and latent heat recovered from the
refrigerant? - ANSWER ✓ Parallel
What is the primary design challenge for CO2 refrigeration systems? - ANSWER
✓ The high operating pressures of CO2 refrigerant
The airflow on a single deck coffin style open display case - ANSWER ✓ Is all
around the product
