RETA | REFRIGERATING ENGINEERS & TECHNICIANS ASSOCIATION
RETA CARO Exam
Certified Assistant Refrigeration Operator
Official Practice Exam | 2026/2027 Edition
Questions: 100 Minutes: 90 Passing Score: 80% Recertification: Annual
Table of Contents
Section 1: Refrigeration Fundamentals & Thermodynamics (25 Questions)
Section 2: Refrigeration System Components & Operation (25 Questions)
Section 3: Safety, Codes & Regulations (20 Questions)
Section 4: System Maintenance, Troubleshooting & Controls (15 Questions)
Section 5: Electrical Fundamentals for Refrigeration (15 Questions)
Instructions
This practice exam contains 100 multiple-choice questions divided into 5 sections. You have 90 minutes to complete the
entire exam. Select the single best answer for each question. A score of 80% or higher (80 out of 100) is required to
pass. Review each rationale carefully to strengthen your understanding of refrigeration principles, system operation,
safety codes, and electrical fundamentals for the RETA CARO certification.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 1 of 52
,Section | Refrigeration Fundamentals & Thermodynamics -- 2026/2027
Q1 Question 1 of 100
A technician is reviewing the basic refrigeration cycle and explains that heat is transferred
from a low-temperature region to a high-temperature region by adding work. This principle
is described by which law of thermodynamics?
A. First law of thermodynamics
B. Second law of thermodynamics
C. Zeroth law of thermodynamics
D. Third law of thermodynamics
Correct Answer: B
Rationale:
The second law of thermodynamics states that heat naturally flows from high-temperature to
low-temperature regions, and that moving heat in the opposite direction requires the input of external
work. The first law addresses energy conservation, and the zeroth law defines thermal equilibrium.
Q2 Question 2 of 100
A refrigeration system operates with an evaporator temperature of 20 deg F and a
condensing temperature of 100 deg F. The technician calculates the amount of heat
absorbed in the evaporator per pound of refrigerant. This quantity is known by which term?
A. Compressor work
B. Refrigeration effect
C. Condenser rejection
D. Superheat value
Correct Answer: B
Rationale:
The refrigeration effect is the amount of heat absorbed by each pound of refrigerant as it evaporates,
typically measured in BTU per pound. Compressor work is the energy input to compress the vapor,
condenser rejection is the total heat removed at the condenser, and superheat is the temperature rise
above saturation.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 2 of 52
,Q3 Question 3 of 100
A plant operator measures the pressure in a refrigeration system and needs to convert
gauge pressure to absolute pressure for calculations. The correct formula for this
conversion adds which value to the gauge pressure?
A. The system design pressure
B. The vapor pressure of the refrigerant
C. The saturation pressure at 32 deg F
D. Atmospheric pressure (14.696 psi)
Correct Answer: D
Rationale:
Absolute pressure equals gauge pressure plus atmospheric pressure (14.696 psi at sea level). This
conversion is essential because thermodynamic tables and calculations use absolute pressure.
Adding system design pressure or vapor pressure would be incorrect.
Q4 Question 4 of 100
A technician observes that a system has a suction pressure of 30 psi gauge using R-22
refrigerant. Using a pressure-temperature chart, the corresponding saturation temperature
is approximately 34 deg F. The actual suction line temperature reads 44 deg F. The
superheat in this system is which value?
A. 10 deg F
B. 14 deg F
C. 34 deg F
D. 44 deg F
Correct Answer: A
Rationale:
Superheat is the difference between the actual suction line temperature and the saturation
temperature corresponding to the suction pressure. In this case, 44 deg F minus 34 deg F equals 10
deg F of superheat. The saturation temperature and actual temperature alone are not the superheat
value.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 3 of 52
, Q5 Question 5 of 100
A refrigeration system uses R-134a and operates with a condensing pressure of 185 psig.
The technician measures the liquid line temperature leaving the condenser at 110 deg F,
while the saturation temperature at 185 psig is 125 deg F. The subcooling in this system is
which value?
A. 35 deg F
B. 110 deg F
C. 15 deg F
D. 125 deg F
Correct Answer: C
Rationale:
Subcooling is the difference between the saturation temperature at condensing pressure and the
actual liquid line temperature. Here, 125 deg F minus 110 deg F equals 15 deg F of subcooling. The
other values represent the actual temperature or saturation temperature alone, not the subcooling.
Q6 Question 6 of 100
A system is charged with a refrigerant that has a latent heat of vaporization of 70 BTU per
pound and a circulation rate of 4 pounds per minute. The system's cooling capacity is
approximately how many BTU per hour?
A. 280 BTU/hr
B. 9,600 BTU/hr
C. 16,800 BTU/hr
D. 4,480 BTU/hr
Correct Answer: C
Rationale:
The cooling capacity equals the latent heat of vaporization multiplied by the mass flow rate: 70 BTU/lb
times 4 lb/min equals 280 BTU/min, times 60 min/hr equals 16,800 BTU/hr. The other values result
from incorrect unit conversions or missing time factors.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 4 of 52
RETA CARO Exam
Certified Assistant Refrigeration Operator
Official Practice Exam | 2026/2027 Edition
Questions: 100 Minutes: 90 Passing Score: 80% Recertification: Annual
Table of Contents
Section 1: Refrigeration Fundamentals & Thermodynamics (25 Questions)
Section 2: Refrigeration System Components & Operation (25 Questions)
Section 3: Safety, Codes & Regulations (20 Questions)
Section 4: System Maintenance, Troubleshooting & Controls (15 Questions)
Section 5: Electrical Fundamentals for Refrigeration (15 Questions)
Instructions
This practice exam contains 100 multiple-choice questions divided into 5 sections. You have 90 minutes to complete the
entire exam. Select the single best answer for each question. A score of 80% or higher (80 out of 100) is required to
pass. Review each rationale carefully to strengthen your understanding of refrigeration principles, system operation,
safety codes, and electrical fundamentals for the RETA CARO certification.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 1 of 52
,Section | Refrigeration Fundamentals & Thermodynamics -- 2026/2027
Q1 Question 1 of 100
A technician is reviewing the basic refrigeration cycle and explains that heat is transferred
from a low-temperature region to a high-temperature region by adding work. This principle
is described by which law of thermodynamics?
A. First law of thermodynamics
B. Second law of thermodynamics
C. Zeroth law of thermodynamics
D. Third law of thermodynamics
Correct Answer: B
Rationale:
The second law of thermodynamics states that heat naturally flows from high-temperature to
low-temperature regions, and that moving heat in the opposite direction requires the input of external
work. The first law addresses energy conservation, and the zeroth law defines thermal equilibrium.
Q2 Question 2 of 100
A refrigeration system operates with an evaporator temperature of 20 deg F and a
condensing temperature of 100 deg F. The technician calculates the amount of heat
absorbed in the evaporator per pound of refrigerant. This quantity is known by which term?
A. Compressor work
B. Refrigeration effect
C. Condenser rejection
D. Superheat value
Correct Answer: B
Rationale:
The refrigeration effect is the amount of heat absorbed by each pound of refrigerant as it evaporates,
typically measured in BTU per pound. Compressor work is the energy input to compress the vapor,
condenser rejection is the total heat removed at the condenser, and superheat is the temperature rise
above saturation.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 2 of 52
,Q3 Question 3 of 100
A plant operator measures the pressure in a refrigeration system and needs to convert
gauge pressure to absolute pressure for calculations. The correct formula for this
conversion adds which value to the gauge pressure?
A. The system design pressure
B. The vapor pressure of the refrigerant
C. The saturation pressure at 32 deg F
D. Atmospheric pressure (14.696 psi)
Correct Answer: D
Rationale:
Absolute pressure equals gauge pressure plus atmospheric pressure (14.696 psi at sea level). This
conversion is essential because thermodynamic tables and calculations use absolute pressure.
Adding system design pressure or vapor pressure would be incorrect.
Q4 Question 4 of 100
A technician observes that a system has a suction pressure of 30 psi gauge using R-22
refrigerant. Using a pressure-temperature chart, the corresponding saturation temperature
is approximately 34 deg F. The actual suction line temperature reads 44 deg F. The
superheat in this system is which value?
A. 10 deg F
B. 14 deg F
C. 34 deg F
D. 44 deg F
Correct Answer: A
Rationale:
Superheat is the difference between the actual suction line temperature and the saturation
temperature corresponding to the suction pressure. In this case, 44 deg F minus 34 deg F equals 10
deg F of superheat. The saturation temperature and actual temperature alone are not the superheat
value.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 3 of 52
, Q5 Question 5 of 100
A refrigeration system uses R-134a and operates with a condensing pressure of 185 psig.
The technician measures the liquid line temperature leaving the condenser at 110 deg F,
while the saturation temperature at 185 psig is 125 deg F. The subcooling in this system is
which value?
A. 35 deg F
B. 110 deg F
C. 15 deg F
D. 125 deg F
Correct Answer: C
Rationale:
Subcooling is the difference between the saturation temperature at condensing pressure and the
actual liquid line temperature. Here, 125 deg F minus 110 deg F equals 15 deg F of subcooling. The
other values represent the actual temperature or saturation temperature alone, not the subcooling.
Q6 Question 6 of 100
A system is charged with a refrigerant that has a latent heat of vaporization of 70 BTU per
pound and a circulation rate of 4 pounds per minute. The system's cooling capacity is
approximately how many BTU per hour?
A. 280 BTU/hr
B. 9,600 BTU/hr
C. 16,800 BTU/hr
D. 4,480 BTU/hr
Correct Answer: C
Rationale:
The cooling capacity equals the latent heat of vaporization multiplied by the mass flow rate: 70 BTU/lb
times 4 lb/min equals 280 BTU/min, times 60 min/hr equals 16,800 BTU/hr. The other values result
from incorrect unit conversions or missing time factors.
RETA CARO Exam -- 2026/2027 | Passing Score: 80% | Page 4 of 52
