New Fdny Z-51 Rsoe Exam |Actual Questions And Verified Answers|Brand New Update | Graded A+

NEW FDNY Z-51 RSOE EXAM |ACTUAL QUESTIONS AND
VERIFIED ANSWERS|BRAND NEW 2026-2027 UPDATE |
GRADED A+



Question 1
Math and Theory
What is the primary purpose of a pressure-temperature (T) chart when servicing a refrigerating
system?

A. To determine electrical motor horsepower
B. To relate refrigerant pressure to its saturation temperature
C. To determine the cooling-tower water flow rate
D. To calculate compressor displacement
CORRECT ANSWER
B..


Question 2
Math and Theory
A refrigerant has a suction pressure of 68 psig. When using the appropriate T chart, what is the
chart primarily used to determine?

A. Saturation temperature
B. Compressor amperage
C. Oil viscosity
D. Condenser water flow
CORRECT ANSWER
A..




1 THE STUD VAULT

,Question 3
Math and Theory
Which statement best describes superheat?

A. The temperature of a liquid above its freezing point
B. The temperature of a vapor above its saturation temperature at a given pressure
C. The temperature of a condenser above outdoor air temperature
D. The pressure difference between suction and discharge
CORRECT ANSWER
B..


Question 4
Math and Theory
Which statement best describes subcooling?

A. Cooling a vapor below its saturation temperature
B. Cooling a liquid below its saturation temperature at a given pressure
C. Raising suction pressure above design
D. Lowering compressor discharge pressure below atmospheric pressure
CORRECT ANSWER
B..


Question 5
Math and Theory
A refrigeration system operates at 60 Hz. What is the period of one complete electrical cycle?

A. 0.0167 s
B. 0.060 s
C. 16.7 s
D. 60 s
CORRECT ANSWER
A..




2 THE STUD VAULT

,Question 6
Math and Theory
Which change generally increases the mass of refrigerant vapor contained in a fixed volume
when temperature is held constant?

A. Decreasing pressure
B. Increasing pressure
C. Decreasing density
D. Removing all heat
CORRECT ANSWER
B..


Question 7
Math and Theory
Which unit is commonly used to express refrigeration capacity?

A. Tons of refrigeration
B. Ohms per second
C. Pounds per square inch absolute
D. Gallons per minute only
CORRECT ANSWER
A..


Question 8
Math and Theory
A pressure gauge reads 30 psig and atmospheric pressure is approximately 14.7 psia. What is the
approximate absolute pressure?

A. 15.3 psia
B. 30.0 psia
C. 44.7 psia
D. 58.7 psia
CORRECT ANSWER
C..




3 THE STUD VAULT

, Question 9
Math and Theory
Which condition represents the greatest risk of liquid refrigerant entering a compressor
designed to compress vapor?

A. Excessive superheat
B. Liquid floodback
C. High discharge superheat only
D. Low condenser water temperature only
CORRECT ANSWER
B..


Question 10
Math and Theory
Why is a basic unit-conversion reference useful during the -51 examination?

A. It replaces all refrigeration theory
B. It helps convert quantities used in calculations and operating data
C. It determines the correct Q-01 applicant eligibility
D. It replaces the refrigerant PT chart
CORRECT ANSWER
B..


Question 11
lant Operations
Before starting a refrigerating plant after a planned shutdown, what is the most appropriate
general approach?

A. Start every motor simultaneously
B. Verify system readiness, safety conditions, and required valves/controls before startup
C. Open every valve fully regardless of its function
D. Bypass all safety controls until operating pressure is reached
CORRECT ANSWER
B..




4 THE STUD VAULT