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Quizzes > Science

HVAC Test Questions: Refrigeration and Air Conditioning Skills

Quick, free HVAC assessment test with instant results.

Editorial: Review CompletedCreated By: Irakli DolidzeUpdated Aug 28, 2025
Difficulty: Moderate
Questions: 20
Learning OutcomesStudy Material
Colorful paper art depicting HVAC and Refrigeration Technical Assessment quiz.

This HVAC and refrigeration test helps you check core knowledge of components, cycles, troubleshooting, and safety. Answer 15 questions, see instant results, and spot skills to review for field work or exams. After you finish, try the hvac troubleshooting quiz, practice with hvac quiz questions, or build basics with the basic hvac knowledge test.

What component compresses refrigerant vapor in a refrigeration cycle?
Condenser
Evaporator
Expansion valve
Compressor
The compressor raises the pressure and temperature of refrigerant vapor, enabling it to flow through the system. It provides the work input necessary for the refrigeration cycle. Without the compressor, the cycle cannot operate.
Which component allows high-pressure liquid refrigerant to expand and lower its pressure?
Compressor
Receiver drier
Heat exchanger coil
Expansion valve
The expansion valve throttles liquid refrigerant, causing a pressure drop and resulting in cooling. This pressure reduction is essential for refrigerant to absorb heat in the evaporator. No other component performs this throttling function.
Which component absorbs heat from indoor air in a refrigeration cycle?
Compressor
Condenser coil
Receiver
Evaporator coil
The evaporator coil is where the refrigerant absorbs heat from indoor air, causing the refrigerant to evaporate. This process produces the cooling effect. Other components either reject heat or compress refrigerant.
What instrument is used to measure refrigerant system pressure?
Thermometer
Manifold gauge set
Anemometer
Ammeter
A manifold gauge set is specifically designed to measure high and low side pressures in refrigeration systems. Technicians use it for charging, evacuating, and diagnosing system pressures. Other instruments measure electrical current, temperature, or airflow.
Which personal protective equipment is essential when handling refrigerant during maintenance?
Safety goggles and gloves
Lab coat and UV glasses
Hard hat and ear muffs
Welding mask and apron
Refrigerants can cause chemical and cold burns, so safety goggles and gloves protect eyes and skin. This basic PPE is mandated by safety protocols when servicing refrigeration equipment. Other options do not adequately protect against refrigerant hazards.
What does the Coefficient of Performance (COP) represent in a refrigeration system?
Ratio of cooling effect to fluid viscosity
Ratio of heat output to power input
Difference between pressure and temperature
Ratio of airflow to electrical current
COP is defined as the ratio of useful heating or cooling provided to the work required. It is a key performance metric for heat pumps and refrigeration systems. Higher COP values indicate more efficient operation.
What does superheat refer to in a refrigeration system?
Subcooling at condenser
Temperature below freezing in evaporator
Pressure above design limits
Temperature above saturation at evaporator outlet
Superheat is the temperature increase of refrigerant vapor above its saturation temperature at a given pressure. It ensures no liquid enters the compressor. Measuring superheat helps verify proper refrigerant charge and evaporator performance.
If a system is undercharged with refrigerant, what symptom is most likely?
Low suction pressure and high superheat
High condenser pressure
Frost on liquid line after condenser
Excessive subcooling
An undercharged system does not supply enough refrigerant, causing low suction pressure and elevated superheat. This reduces cooling capacity and can lead to compressor overheating. Other symptoms are associated with overcharge or other faults.
What does EPA Section 608 certification regulate?
Installation of ductwork
Flue gas analysis
Certification of electricians
Handling and disposal of refrigerants
EPA Section 608 certification is required for technicians who service, maintain, or dispose of equipment containing regulated refrigerants. It ensures proper handling to protect the ozone layer. It does not cover ductwork or electrical certification.
Which refrigerant has zero ozone depletion potential (ODP)?
R-134a
R-22
R-502
R-12
R-134a is a hydrofluorocarbon (HFC) with an ODP of zero, meaning it does not deplete the ozone layer. Other older refrigerants like R-12 and R-502 have higher ODPs. R-22 has a nonzero ODP and is being phased out.
Frost forming on a suction line near the compressor most likely indicates what issue?
Excess refrigerant charge
Restricted airflow across the evaporator
Faulty condenser fan motor
High ambient temperature
Restricted airflow reduces heat absorption in the evaporator, causing excessive cooling of the suction line and frosting. Proper airflow is essential to maintain correct evaporator temperature. Other issues would present different pressure or temperature symptoms.
To calculate superheat, a technician measures the evaporator outlet temperature at 50°F and saturation temperature from pressure at 40°F. What is the superheat?
5°F
20°F
40°F
10°F
Superheat is calculated as the difference between actual vapor temperature (50°F) and saturation temperature (40°F), which equals 10°F. Correct superheat ensures vaporized refrigerant enters the compressor. Incorrect values indicate charge or metering faults.
What is the purpose of a sight glass in a refrigeration system?
To observe refrigerant condition and detect bubbles
To measure airflow across coils
To regulate system pressure
To filter out moisture from refrigerant
A sight glass lets technicians see liquid refrigerant flow and check for bubbles, indicating correct charge and moisture presence. Bubbles suggest undercharge or moisture. It does not filter or regulate pressure directly.
Which tool is best for evacuating moisture from a refrigeration system?
Mechanical vacuum pump
Refrigerant scale
Air compressor
Refrigerant recovery machine
A mechanical vacuum pump creates deep vacuum levels to remove air and moisture from the system. Proper evacuation prevents ice and corrosion. Recovery machines reclaim refrigerant but do not achieve the vacuum needed for moisture removal.
What is subcooling in a refrigeration cycle?
Temperature rise in the compressor
Degree vapor is heated above saturation
Degree liquid refrigerant is cooled below its saturation temperature
Pressure drop across the expansion valve
Subcooling is the amount by which liquid refrigerant is cooled below its condensation temperature. It ensures only liquid enters the expansion device, improving system efficiency. It is distinct from superheat.
A heat pump delivers 60,000 BTU/h of heating while consuming 12,000 BTU/h of electrical power. What is its COP?
4
5
6
3
COP is calculated as heating output divided by electrical input: 60,000 BTU/h ÷ 12,000 BTU/h = 5. A COP of 5 means the heat pump delivers five units of heat for every unit of power. Higher values denote greater efficiency.
What vacuum level in microns indicates adequate evacuation for moisture removal in a refrigeration system?
1,500 microns
10,000 microns
50 microns or lower
500 microns or lower
A vacuum level of 500 microns or lower is typically required to remove moisture and non-condensables effectively. Achieving this deep vacuum ensures proper system dehydration. Higher micron readings indicate residual moisture or air.
According to ASHRAE refrigerant safety classifications, what does the designation A2L indicate?
Low toxicity, lower flammability
High toxicity, nonflammable
Low toxicity, nonflammable
High toxicity, high flammability
ASHRAE designation A2L means the refrigerant has low toxicity (A) and lower flammability (2L). It requires special handling due to slight flammability risk. Other groups cover nonflammable or highly toxic/flamable classes.
When retrofitting an R-22 system to R-410A, what oil change is necessary?
Maintain existing mineral oil with no change
Switch to alkylbenzene oil only
Replace mineral oil with POE oil and flush the system
Add 50% additional mineral oil
R-410A requires polyolester (POE) oil for compatibility and lubrication. Mineral oil used with R-22 is not miscible with R-410A. A thorough flush and POE oil replacement are mandatory for proper operation.
A compressor exhibits normal suction pressure but reduced capacity and elevated discharge temperature. Which internal fault is most likely?
Malfunctioning condenser fan
Blocked liquid line filter
Failed discharge valve
Leaking suction valve
A failed discharge valve allows backflow of high-pressure vapor into the suction side during compression, reducing capacity and increasing discharge gas temperature. Suction pressure may appear normal. Other faults present different pressure signatures.
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Learning Outcomes

  1. Analyse core HVAC system components and their functions.
  2. Evaluate refrigeration cycle principles and performance metrics.
  3. Identify common troubleshooting issues in HVAC equipment.
  4. Apply safety protocols for refrigeration maintenance and handling.
  5. Demonstrate understanding of refrigerant properties and regulations.
  6. Master proper selection of HVAC and refrigeration tools.

Cheat Sheet

  1. Understand the Core Components of HVAC Systems - Think of HVAC parts as teammates: the heat exchanger warms or cools air, the blower motor moves it around, and the thermostat greets your settings. When each part plays its role, your comfort zone stays balanced.
  2. Master the Refrigeration Cycle - Dive into the magical loop of evaporation, compression, condensation, and expansion that makes cooling possible. This cycle shows how refrigerant steals heat from inside and releases it outdoors - kind of like a microscopic superhero.
  3. Calculate the Coefficient of Performance (COP) - COP measures how much heating or cooling power you get for each unit of energy you spend. A higher COP means your system is working smarter, not harder, and your energy bills thank you!
  4. Identify Common HVAC Troubleshooting Issues - From sneaky refrigerant leaks to clogged filters and quirky thermostats, knowing the usual suspects saves time and keeps things running smoothly. Spotting trouble early is like catching a villain before they wreak havoc on your system.
  5. Apply Safety Protocols in Refrigeration Maintenance - Suit up with safety glasses, gloves, and good ventilation when handling refrigerants. Following protocols not only protects you but also guards our planet's ozone layer - superhero moves in the real world!
  6. Understand Refrigerant Properties and Regulations - Each refrigerant has its own temperature range, pressure limits, and environmental rules. Staying up-to-date on regulations ensures you're cool with the law and cool in your room.
  7. Select Appropriate HVAC and Refrigeration Tools - Whether you're measuring pressure or hunting for leaks, the right tool is your secret weapon. Investing in quality gauges and detectors means faster diagnostics and high-fives from your future self.
  8. Grasp the Function of the Air Handler - The air handler is the system's lungs, pushing air through filters, coils, and vents. Understanding its inner parts helps you troubleshoot airflow dramas and keep fresh air circulating.
  9. Learn About Heat Exchangers - Heat exchangers are the silent powerhouses swapping heat between fluids without mixing them. Mastering their types and designs can boost your system's efficiency and save energy.
  10. Understand the Role of the Thermostat - The thermostat is your system's brain, translating temperature preferences into action. Smart or programmable, it's the small gadget that makes huge energy savings possible.
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