District of Columbia Journeyman A/C and
Refrigeration (312) Exam Prep 200-Question
Practice Exam with Answers & Explanations
(2026 Edition) PDF
Exam Overview
The DC 312 exam is designed to test your mastery of
the International Mechanical Code (IMC) and the practical
application of refrigeration theory.
Testing Agency: DLCP (District of Columbia).
Primary References: 2012 International Mechanical
Code and Modern Refrigeration and Air Conditioning.
Key Features of the Exam
Code Heavy: A significant portion of the exam requires navigating the
IMC to find specific installation requirements (clearances, duct sizing,
and piping).
Electrical Focus: You will be tested on reading schematics,
identifying capacitor types, and troubleshooting motor failures.
Refrigeration Cycle: Expect deep-dive questions on subcooling,
superheat, and the chemical properties of different refrigerants (R-22,
R-410A, R-134a).
Safety & EPA: Knowledge of EPA Section 608 (recovery, recycling,
and reclamation) and OSHA safety standards for pressurized vessels.
1. What is the primary purpose of a filter-drier in a refrigeration
system?
, A) To increase subcooling
B) To remove moisture and contaminants
C) To regulate refrigerant flow
D) To act as a heat exchanger
Correct Answer: B
Filter-driers use desiccant to absorb moisture and a fine mesh to catch
debris, preventing acid formation and compressor damage.
2. According to the IMC, what is the minimum unobstructed
workspace required in front of an HVAC unit?
A) 12 inches
B) 24 inches
C) 30 inches
D) 36 inches
Correct Answer: C
The International Mechanical Code generally requires 30 inches of
width and 30 inches of depth for service access.
3. In a standard refrigeration cycle, where does the refrigerant
change from a high-pressure vapor to a high-pressure liquid?
A) Evaporator
B) Compressor
C) Condenser
D) Expansion Valve
Correct Answer: C
The condenser removes heat from the high-pressure vapor, causing it
to condense into a liquid.
4. Which tool is used to measure a vacuum in microns?
A) Compound gauge
B) Manometer
C) Micron gauge
D) Psychrometer
Correct Answer: C
Standard manifold gauges are not sensitive enough to measure deep
vacuums; a dedicated electronic micron gauge is required.
,5. A "Thermocouple" produces power in which form?
A) AC Volts
B) Millivolts DC
C) Ohms
D) Amps
Correct Answer: B
A thermocouple uses two dissimilar metals to convert heat into a small
DC voltage, typically around 30 millivolts.
6. What is the boiling point of R-22 at atmospheric pressure?
A) -40.8°F
B) 32°F
C) 0°F
D) -15.5°F
Correct Answer: A
R-22 has a boiling point of approximately -40.8°F at sea level (0 psig).
7. A motor that uses a Start Capacitor and a Run Capacitor is
known as a:
A) Shaded pole motor
B) Split-phase motor
C) CSCR motor
D) Three-phase motor
Correct Answer: C
Capacitor Start, Capacitor Run (CSCR) motors provide high starting
torque and high operating efficiency.
8. "Superheat" is measured at which location?
A) Outlet of the condenser
B) Inlet of the evaporator
C) Outlet of the evaporator
D) Inlet of the condenser
Correct Answer: C
Superheat is the temperature of the vapor above its saturation point,
measured at the end of the evaporator to ensure no liquid reaches the
compressor.
, 9. What happens to the resistance of a NTC Thermistor as the
temperature increases?
A) Resistance increases
B) Resistance stays the same
C) Resistance decreases
D) Resistance fluctuates
Correct Answer: C
Negative Temperature Coefficient (NTC) sensors see a drop in
resistance as they get warmer.
10. The process of removing refrigerant from a system and
storing it in an external container is called:
A) Recycling
B) Reclamation
C) Recovery
D) Charging
Correct Answer: C
Recovery is the simple removal and storage of refrigerant without
necessarily testing or processing it.
11. In the IMC, condensate piping must maintain a minimum
slope of:
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Correct Answer: B
The code requires a minimum 1 percent slope, which equates to 1/8
inch of fall per foot of run.
12. A "Solenoid Valve" is operated by:
A) Air pressure
B) Water flow
C) Electromagnetism
D) Manual turning
Correct Answer: C
Refrigeration (312) Exam Prep 200-Question
Practice Exam with Answers & Explanations
(2026 Edition) PDF
Exam Overview
The DC 312 exam is designed to test your mastery of
the International Mechanical Code (IMC) and the practical
application of refrigeration theory.
Testing Agency: DLCP (District of Columbia).
Primary References: 2012 International Mechanical
Code and Modern Refrigeration and Air Conditioning.
Key Features of the Exam
Code Heavy: A significant portion of the exam requires navigating the
IMC to find specific installation requirements (clearances, duct sizing,
and piping).
Electrical Focus: You will be tested on reading schematics,
identifying capacitor types, and troubleshooting motor failures.
Refrigeration Cycle: Expect deep-dive questions on subcooling,
superheat, and the chemical properties of different refrigerants (R-22,
R-410A, R-134a).
Safety & EPA: Knowledge of EPA Section 608 (recovery, recycling,
and reclamation) and OSHA safety standards for pressurized vessels.
1. What is the primary purpose of a filter-drier in a refrigeration
system?
, A) To increase subcooling
B) To remove moisture and contaminants
C) To regulate refrigerant flow
D) To act as a heat exchanger
Correct Answer: B
Filter-driers use desiccant to absorb moisture and a fine mesh to catch
debris, preventing acid formation and compressor damage.
2. According to the IMC, what is the minimum unobstructed
workspace required in front of an HVAC unit?
A) 12 inches
B) 24 inches
C) 30 inches
D) 36 inches
Correct Answer: C
The International Mechanical Code generally requires 30 inches of
width and 30 inches of depth for service access.
3. In a standard refrigeration cycle, where does the refrigerant
change from a high-pressure vapor to a high-pressure liquid?
A) Evaporator
B) Compressor
C) Condenser
D) Expansion Valve
Correct Answer: C
The condenser removes heat from the high-pressure vapor, causing it
to condense into a liquid.
4. Which tool is used to measure a vacuum in microns?
A) Compound gauge
B) Manometer
C) Micron gauge
D) Psychrometer
Correct Answer: C
Standard manifold gauges are not sensitive enough to measure deep
vacuums; a dedicated electronic micron gauge is required.
,5. A "Thermocouple" produces power in which form?
A) AC Volts
B) Millivolts DC
C) Ohms
D) Amps
Correct Answer: B
A thermocouple uses two dissimilar metals to convert heat into a small
DC voltage, typically around 30 millivolts.
6. What is the boiling point of R-22 at atmospheric pressure?
A) -40.8°F
B) 32°F
C) 0°F
D) -15.5°F
Correct Answer: A
R-22 has a boiling point of approximately -40.8°F at sea level (0 psig).
7. A motor that uses a Start Capacitor and a Run Capacitor is
known as a:
A) Shaded pole motor
B) Split-phase motor
C) CSCR motor
D) Three-phase motor
Correct Answer: C
Capacitor Start, Capacitor Run (CSCR) motors provide high starting
torque and high operating efficiency.
8. "Superheat" is measured at which location?
A) Outlet of the condenser
B) Inlet of the evaporator
C) Outlet of the evaporator
D) Inlet of the condenser
Correct Answer: C
Superheat is the temperature of the vapor above its saturation point,
measured at the end of the evaporator to ensure no liquid reaches the
compressor.
, 9. What happens to the resistance of a NTC Thermistor as the
temperature increases?
A) Resistance increases
B) Resistance stays the same
C) Resistance decreases
D) Resistance fluctuates
Correct Answer: C
Negative Temperature Coefficient (NTC) sensors see a drop in
resistance as they get warmer.
10. The process of removing refrigerant from a system and
storing it in an external container is called:
A) Recycling
B) Reclamation
C) Recovery
D) Charging
Correct Answer: C
Recovery is the simple removal and storage of refrigerant without
necessarily testing or processing it.
11. In the IMC, condensate piping must maintain a minimum
slope of:
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Correct Answer: B
The code requires a minimum 1 percent slope, which equates to 1/8
inch of fall per foot of run.
12. A "Solenoid Valve" is operated by:
A) Air pressure
B) Water flow
C) Electromagnetism
D) Manual turning
Correct Answer: C
