NJ BLUE SEAL REFRIGERATION Exam 3
Questions And Verified Answers
2025(Graded A+) Detailed Answers
Which of the following compressors does not require inlet or
discharge valves?
Sliding valve
Which of the following formulas would you use to calculate
the relieving capacity of a safety valve?
W = A X (P + 10) / .2
If a stuffing box bore on a pump measured 4 inches and the
pumps shaft is 3 1/4, what size should be used?
3/8 inch
What is the term used to describe the difference in the speed
of the rotor and field in an induction motor?
Slip speed
What would be one standard atmosphere at 14.7 lb sq inch in
feet of water?
34 feet
An adjustment has just been completed of the packing gland
of an automatic valve to stop a minor leak. Which of the
following can occur if the technician over tightened the
packing gland?
Increased stroke time from fully open to fully closed
If a pump discharge pressure gauge indicates 225 psi, what
would be the head in feet?
525 ft. lb
What would occur if there was a drop in velocity of the fluid
flow through a heat exchanger?
,The temperature of a fluid would increase
What is the formula used to calculate the speed of a
synchronous motor?
120 x F / P
If a vacuum gauge reads 24" Hg, what would the reading be
in pounds per square inch?
11.76 psi
If the stuffing box bore on a pump measured 4 inches and
the pump shaft is 3 1/4 inches , what size packing should be
used?
3/8 inch
What suction performance factor is a characteristic of the
pump an varies with pump design, size and operating
conditions?
Net positive suction head
If two similar centrifugal pumps were connected in parallel,
there would be:
Flow increase with pressure being constant
Which of the following would be considered a false
statement about the operation of rotary pumps?
All of the answers
Compare a typical gate valve to a typical globe valve in the
same application in an operating high pressure cooling water
system. If both valves are fully open, the gate valve will have
a BLANK pressure drop and the better choice
for BLANK flow.
Lower / Isolating
What is the purpose of wearing rings found on a centrifugal
pump?
To increase efficiency
The ratio of the density of a substance to the density of an
established standard substance (water) is known as?
, Specific gravity
What suction performance factor is a characteristic of the
pump and varies with pump design, size and operating
conditions?
Net positive suction head
What term is used to describe the sum of the friction head,
the velocity head and the pressure head?
Dynamic head
On a single acting reciprocating compressor, what is the
function of a dual control device?
It allows constant speed control and automatic starts and stops
If a system were using an automatic expansion valve, what
would the constant pressure be maintained at?
The evaporator
What is the main advantage of a cascade refrigeration
system?
Capable of reaching very low temperature
Choose the statement below, which would prove false about
lithium bromide used in absorption systems?
It is non-corrosive
What is a sling psychrometer device used to measure?
Relative humidity
A system using an evaporative condenser operates most
efficiently under what conditions?
When the wet-bulb temperature of air is low
the discharge gas from the compressor is what, in a wet-
compression refrigeration system?
Saturated
If a refrigeration system were over charged with refrigerant,
what conditions would occur?
Decrease in capacity and increase in head pressure
Questions And Verified Answers
2025(Graded A+) Detailed Answers
Which of the following compressors does not require inlet or
discharge valves?
Sliding valve
Which of the following formulas would you use to calculate
the relieving capacity of a safety valve?
W = A X (P + 10) / .2
If a stuffing box bore on a pump measured 4 inches and the
pumps shaft is 3 1/4, what size should be used?
3/8 inch
What is the term used to describe the difference in the speed
of the rotor and field in an induction motor?
Slip speed
What would be one standard atmosphere at 14.7 lb sq inch in
feet of water?
34 feet
An adjustment has just been completed of the packing gland
of an automatic valve to stop a minor leak. Which of the
following can occur if the technician over tightened the
packing gland?
Increased stroke time from fully open to fully closed
If a pump discharge pressure gauge indicates 225 psi, what
would be the head in feet?
525 ft. lb
What would occur if there was a drop in velocity of the fluid
flow through a heat exchanger?
,The temperature of a fluid would increase
What is the formula used to calculate the speed of a
synchronous motor?
120 x F / P
If a vacuum gauge reads 24" Hg, what would the reading be
in pounds per square inch?
11.76 psi
If the stuffing box bore on a pump measured 4 inches and
the pump shaft is 3 1/4 inches , what size packing should be
used?
3/8 inch
What suction performance factor is a characteristic of the
pump an varies with pump design, size and operating
conditions?
Net positive suction head
If two similar centrifugal pumps were connected in parallel,
there would be:
Flow increase with pressure being constant
Which of the following would be considered a false
statement about the operation of rotary pumps?
All of the answers
Compare a typical gate valve to a typical globe valve in the
same application in an operating high pressure cooling water
system. If both valves are fully open, the gate valve will have
a BLANK pressure drop and the better choice
for BLANK flow.
Lower / Isolating
What is the purpose of wearing rings found on a centrifugal
pump?
To increase efficiency
The ratio of the density of a substance to the density of an
established standard substance (water) is known as?
, Specific gravity
What suction performance factor is a characteristic of the
pump and varies with pump design, size and operating
conditions?
Net positive suction head
What term is used to describe the sum of the friction head,
the velocity head and the pressure head?
Dynamic head
On a single acting reciprocating compressor, what is the
function of a dual control device?
It allows constant speed control and automatic starts and stops
If a system were using an automatic expansion valve, what
would the constant pressure be maintained at?
The evaporator
What is the main advantage of a cascade refrigeration
system?
Capable of reaching very low temperature
Choose the statement below, which would prove false about
lithium bromide used in absorption systems?
It is non-corrosive
What is a sling psychrometer device used to measure?
Relative humidity
A system using an evaporative condenser operates most
efficiently under what conditions?
When the wet-bulb temperature of air is low
the discharge gas from the compressor is what, in a wet-
compression refrigeration system?
Saturated
If a refrigeration system were over charged with refrigerant,
what conditions would occur?
Decrease in capacity and increase in head pressure
