NJ BLUE SEAL REFRIGERATION Exam Questions
And Verified Answers 2025 Detailed Answers
What type of heat exchange occurs at the exterior sides of a
cooling tower?
Convection
What is true regarding the compression ratio of a
reciprocating compressor?
Ratio varies according to the conditions under which it operates
If the high side float were to fill with liquid and sink, what
would be the result?
The evaporator would starve for refrigerant
In a refrigeration system, what part would be considered the
low side?
Between the evaporator and the compressor
Why is a horizontal shell and tube condenser more efficient
than a vertical shell and tube condenser?
It has more than one pass
What is the maximum amount of refrigerant allowed in a 120
lb. cylinder?
96 lbs..
one ton of refrigeration equals?
The removal of 12,000 Btu/hr
Describe the operation of a synchronous motor
Starts on AC, operates on AC/DC
Define the operation of the valves of a refrigeration
compressor:
They are opened and closed by pressure difference
Where is oiling required on a centrifugal refrigeration
system?
,At the shaft end bearings
If water is leaving an efficiently operating induced draft
cooling tower, what is the temperature of the water?
Between the wet bulb and the dry bulb temperature of the air
What determines the low side pressure in a refrigeration
system?
The evaporator flow rate
What is the reason for subcooling the refrigerant?
To increase the refrigerating effect
What would not cause a noisy compressor?
Flash gas in the evaporator
Which type of motor is typically used on condenser and
evaporator motors?
Squirrel cage motors
If a reciprocating compressor were run with the suction valve
closed and the discharge valve open, what would occur?
Non-condensables would enter the compressor
What is the position of the suction and discharge valves
when the piston is at top dead center?
Both closed
Express Ohm's Law as a formula?
E=IxR
What is the maximum amount of refrigerant you can put in a
250 lb. cylinder?
200 lbs
What motor circuit is de-energized after the compressor
comes up to speed?
Start winding
State Boyle's Law as a formula:
P1 x V1 = P2 x V2
, How do the unloaders unload the pistons on a reciprocating
compressor?
They bypass discharge gas back into the compressor suction
The volume of a refrigerant under a specific pressure and
temperature is called?
Specific volume
In an automatic expansion valve system, constant pressure
is maintained at the:
Evaporator inlet
How do the valves on a compressor operate?
By pressure
Convert 5 degrees F to Degrees C
-15 C
What is an advantage of a cascade refrigeration system?
Capable of very low temperature
The evaporator absorbs heat from the air or brine because
the liquid refrigerant entering the evaporator:
Has a lower temperature than the air or brine
What is the purpose of a stuffing box seal?
It prevents refrigerant leaks from the crankcase
Packing in the stuffing box is:
Made of metal with oil running through
As capacity decreases in a reciprocating compressor:
Suction pressure decreases
What would happen if you overcharge a system with
refrigerant?
Decreased efficiency, high head pressure, decreased capacity
Heat that increases the temperature of a refrigerant without a
change of state is:
Sensible heat
A condenser water pH of 10 is considered to be:
And Verified Answers 2025 Detailed Answers
What type of heat exchange occurs at the exterior sides of a
cooling tower?
Convection
What is true regarding the compression ratio of a
reciprocating compressor?
Ratio varies according to the conditions under which it operates
If the high side float were to fill with liquid and sink, what
would be the result?
The evaporator would starve for refrigerant
In a refrigeration system, what part would be considered the
low side?
Between the evaporator and the compressor
Why is a horizontal shell and tube condenser more efficient
than a vertical shell and tube condenser?
It has more than one pass
What is the maximum amount of refrigerant allowed in a 120
lb. cylinder?
96 lbs..
one ton of refrigeration equals?
The removal of 12,000 Btu/hr
Describe the operation of a synchronous motor
Starts on AC, operates on AC/DC
Define the operation of the valves of a refrigeration
compressor:
They are opened and closed by pressure difference
Where is oiling required on a centrifugal refrigeration
system?
,At the shaft end bearings
If water is leaving an efficiently operating induced draft
cooling tower, what is the temperature of the water?
Between the wet bulb and the dry bulb temperature of the air
What determines the low side pressure in a refrigeration
system?
The evaporator flow rate
What is the reason for subcooling the refrigerant?
To increase the refrigerating effect
What would not cause a noisy compressor?
Flash gas in the evaporator
Which type of motor is typically used on condenser and
evaporator motors?
Squirrel cage motors
If a reciprocating compressor were run with the suction valve
closed and the discharge valve open, what would occur?
Non-condensables would enter the compressor
What is the position of the suction and discharge valves
when the piston is at top dead center?
Both closed
Express Ohm's Law as a formula?
E=IxR
What is the maximum amount of refrigerant you can put in a
250 lb. cylinder?
200 lbs
What motor circuit is de-energized after the compressor
comes up to speed?
Start winding
State Boyle's Law as a formula:
P1 x V1 = P2 x V2
, How do the unloaders unload the pistons on a reciprocating
compressor?
They bypass discharge gas back into the compressor suction
The volume of a refrigerant under a specific pressure and
temperature is called?
Specific volume
In an automatic expansion valve system, constant pressure
is maintained at the:
Evaporator inlet
How do the valves on a compressor operate?
By pressure
Convert 5 degrees F to Degrees C
-15 C
What is an advantage of a cascade refrigeration system?
Capable of very low temperature
The evaporator absorbs heat from the air or brine because
the liquid refrigerant entering the evaporator:
Has a lower temperature than the air or brine
What is the purpose of a stuffing box seal?
It prevents refrigerant leaks from the crankcase
Packing in the stuffing box is:
Made of metal with oil running through
As capacity decreases in a reciprocating compressor:
Suction pressure decreases
What would happen if you overcharge a system with
refrigerant?
Decreased efficiency, high head pressure, decreased capacity
Heat that increases the temperature of a refrigerant without a
change of state is:
Sensible heat
A condenser water pH of 10 is considered to be:
