NYC Refrigeration Operating Engineer License Exam 2026 – 190
Professional Certification Practice Questions with Answers &
Detailed Rationales, Refrigeration Systems, Compressors,
Refrigerants, Maintenance, Fire Safety & NYC Code Compliance
SECTION 1: REFRIGERATION FUNDAMENTALS & THERMODYNAMICS (Questions 1–25)
Question 1
What is the definition of one ton of refrigeration?
A. The heat required to raise one ton of water by 1°F
B. The heat removal rate of 12,000 BTU per hour
C. The heat required to melt one ton of ice in one hour
D. The heat removal rate of 144 BTU per hour
Correct Answer: B
Explanation: One ton of refrigeration equals 12,000 BTU/hr, derived from melting one ton of
ice over 24 hours.
Question 2
How many BTUs are required to melt one pound of ice at 32°F into water at 32°F?
A. 1 BTU
B. 33 BTU
C. 144 BTU
D. 970 BTU
,Correct Answer: C
Explanation: The latent heat of fusion for water/ice is 144 BTU per pound, representing
energy absorbed without temperature change.
Question 3
What is the latent heat of vaporization of water at atmospheric pressure?
A. 144 BTU per pound
B. 180 BTU per pound
C. 970 BTU per pound
D. 1,000 BTU per pound
Correct Answer: C
Explanation: Water absorbs approximately 970 BTU per pound when changing from liquid to
vapor at 212°F.
Question 4
Which statement correctly distinguishes sensible heat from latent heat?
A. Sensible heat causes a phase change; latent heat causes a temperature change
B. Sensible heat causes a temperature change; latent heat causes a phase change
C. Both cause temperature changes without phase transitions
D. Both cause phase transitions without temperature changes
Correct Answer: B
,Explanation: Sensible heat changes measurable temperature; latent heat is absorbed or
rejected during phase change at constant temperature.
Question 5
In a vapor-compression refrigeration system, what is the primary function of the
compressor?
A. Absorb heat from the refrigerated space
B. Reject heat to the atmosphere
C. Raise refrigerant vapor pressure and circulate refrigerant
D. Reduce refrigerant pressure before the evaporator
Correct Answer: C
Explanation: The compressor draws low-pressure vapor and compresses it, raising pressure
and temperature to enable heat rejection.
Question 6
Which component receives low-pressure vapor directly from the evaporator in a basic
refrigeration cycle?
A. Condenser
B. Expansion valve
C. Compressor
D. Receiver
Correct Answer: C
, Explanation: The compressor is the first component after the evaporator, drawing in low-
pressure vapor for compression.
Question 7
What is the primary function of the condenser in a refrigeration system?
A. Absorb heat from the refrigerated space
B. Remove heat from high-pressure refrigerant vapor
C. Increase refrigerant pressure
D. Meter refrigerant flow
Correct Answer: B
Explanation: The condenser removes heat from compressed vapor, causing it to condense
into liquid.
Question 8
What is the primary function of the evaporator?
A. Increase refrigerant pressure
B. Absorb heat from the refrigerated space
C. Reject heat to the environment
D. Compress refrigerant vapor
Correct Answer: B
Explanation: The evaporator absorbs heat from the space being cooled as low-pressure
liquid refrigerant boils into vapor.
Professional Certification Practice Questions with Answers &
Detailed Rationales, Refrigeration Systems, Compressors,
Refrigerants, Maintenance, Fire Safety & NYC Code Compliance
SECTION 1: REFRIGERATION FUNDAMENTALS & THERMODYNAMICS (Questions 1–25)
Question 1
What is the definition of one ton of refrigeration?
A. The heat required to raise one ton of water by 1°F
B. The heat removal rate of 12,000 BTU per hour
C. The heat required to melt one ton of ice in one hour
D. The heat removal rate of 144 BTU per hour
Correct Answer: B
Explanation: One ton of refrigeration equals 12,000 BTU/hr, derived from melting one ton of
ice over 24 hours.
Question 2
How many BTUs are required to melt one pound of ice at 32°F into water at 32°F?
A. 1 BTU
B. 33 BTU
C. 144 BTU
D. 970 BTU
,Correct Answer: C
Explanation: The latent heat of fusion for water/ice is 144 BTU per pound, representing
energy absorbed without temperature change.
Question 3
What is the latent heat of vaporization of water at atmospheric pressure?
A. 144 BTU per pound
B. 180 BTU per pound
C. 970 BTU per pound
D. 1,000 BTU per pound
Correct Answer: C
Explanation: Water absorbs approximately 970 BTU per pound when changing from liquid to
vapor at 212°F.
Question 4
Which statement correctly distinguishes sensible heat from latent heat?
A. Sensible heat causes a phase change; latent heat causes a temperature change
B. Sensible heat causes a temperature change; latent heat causes a phase change
C. Both cause temperature changes without phase transitions
D. Both cause phase transitions without temperature changes
Correct Answer: B
,Explanation: Sensible heat changes measurable temperature; latent heat is absorbed or
rejected during phase change at constant temperature.
Question 5
In a vapor-compression refrigeration system, what is the primary function of the
compressor?
A. Absorb heat from the refrigerated space
B. Reject heat to the atmosphere
C. Raise refrigerant vapor pressure and circulate refrigerant
D. Reduce refrigerant pressure before the evaporator
Correct Answer: C
Explanation: The compressor draws low-pressure vapor and compresses it, raising pressure
and temperature to enable heat rejection.
Question 6
Which component receives low-pressure vapor directly from the evaporator in a basic
refrigeration cycle?
A. Condenser
B. Expansion valve
C. Compressor
D. Receiver
Correct Answer: C
, Explanation: The compressor is the first component after the evaporator, drawing in low-
pressure vapor for compression.
Question 7
What is the primary function of the condenser in a refrigeration system?
A. Absorb heat from the refrigerated space
B. Remove heat from high-pressure refrigerant vapor
C. Increase refrigerant pressure
D. Meter refrigerant flow
Correct Answer: B
Explanation: The condenser removes heat from compressed vapor, causing it to condense
into liquid.
Question 8
What is the primary function of the evaporator?
A. Increase refrigerant pressure
B. Absorb heat from the refrigerated space
C. Reject heat to the environment
D. Compress refrigerant vapor
Correct Answer: B
Explanation: The evaporator absorbs heat from the space being cooled as low-pressure
liquid refrigerant boils into vapor.
