DISTRICT OF COLUMBIA (DC) JOURNEYMAN A/C & REFRIGERATION UPDATED EXAM QUESTIONS AND CORRECT ANSWERS WITH GUARANTEED PASS

1. Which component meters refrigerant flow into the evaporator in most
systems?
A. Compressor
B. Condenser
C. Expansion valve
D. Receiver
ANSWER : C
Explanation: The expansion valve controls and meters the amount of
refrigerant entering the evaporator, reducing pressure and temperature.


2. Refrigerant absorbs heat in which component?
A. Condenser
B. Compressor
C. Evaporator
D. Liquid line
ANSWER : C
Explanation: Heat is absorbed in the evaporator as the refrigerant changes from
liquid to vapor.


3. What state does refrigerant leave the evaporator in?
A. High-pressure liquid
B. Low-pressure vapor
C. High-pressure vapor
D. Saturated liquid
ANSWER : B
Explanation: Refrigerant leaves the evaporator as a low-pressure vapor.

,4. Which refrigerant is most commonly used to replace R-22?
A. R-12
B. R-134a
C. R-410A
D. R-404A
ANSWER : C
Explanation: R-410A is the most common replacement for R-22 in residential
and light commercial systems.


5. What is the primary function of a compressor?
A. Store refrigerant
B. Remove moisture
C. Increase refrigerant pressure
D. Meter refrigerant flow
ANSWER : C
Explanation: The compressor raises refrigerant pressure and temperature so
heat can be rejected in the condenser.


6. What happens to refrigerant pressure in the condenser?
A. Decreases
B. Remains constant
C. Increases then decreases
D. Remains high
ANSWER : D
Explanation: Refrigerant remains at high pressure while releasing heat in the
condenser.


7. Which device protects the compressor from excessive pressure?
A. Thermostat
B. Low-pressure switch
C. High-pressure switch
D. Solenoid valve

, ANSWER : C
Explanation: A high-pressure switch shuts the system down if pressure exceeds
safe limits.


8. Superheat is measured at the:
A. Condenser outlet
B. Compressor discharge
C. Evaporator outlet
D. Liquid line
ANSWER : C
Explanation: Superheat is measured at the evaporator outlet to ensure no liquid
refrigerant enters the compressor.


9. Subcooling is measured at the:
A. Evaporator inlet
B. Compressor suction line
C. Condenser outlet
D. Expansion valve inlet
ANSWER : C
Explanation: Subcooling is measured at the condenser outlet to ensure
refrigerant is fully liquid.


10. Excessive superheat indicates:
A. Overcharged system
B. Restricted airflow
C. Undercharged system
D. Faulty compressor
ANSWER : C
Explanation: High superheat usually means insufficient refrigerant flow
(undercharge or restriction).


11. What tool is used to remove moisture from a refrigeration system?

, A. Recovery machine
B. Vacuum pump
C. Manifold gauge
D. Nitrogen tank
ANSWER : B
Explanation: A vacuum pump removes air and moisture before charging.


12. Moisture in a system can cause:
A. Better cooling
B. Ice formation
C. Higher efficiency
D. Reduced pressure
ANSWER : B
Explanation: Moisture can freeze and block refrigerant flow, damaging
components.


13. Which oil is used with R-410A systems?
A. Mineral oil
B. Alkylbenzene
C. POE oil
D. PAG oil
ANSWER : C
Explanation: Polyolester (POE) oil is required for R-410A systems.


14. What happens when airflow across the evaporator is low?
A. High superheat
B. Coil freezing
C. Increased efficiency
D. Reduced head pressure
ANSWER : B
Explanation: Low airflow causes the evaporator temperature to drop, leading
to ice formation.