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HVAC EXCELLENCE PROFESSIONAL
TECHNICIAN CERTIFICATION
EXAMINATION QUESTION AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
- Which law states that pressure and temperature of a gas are directly proportional at constant volume? A. Boyle’s Law B. Gay-Lussac’s Law C. Charles’s Law D. Dalton’s Law _ Gay-Lussac’s Law explains the direct relationship between pressure and temperature when volume is constant. _**
- What refrigerant is commonly used in residential air conditioning systems manufactured after 2010? A. R- 22 B. R-410A C. R- 12 D. R- 502 _ R-410A replaced R-22 due to environmental regulations and higher efficiency. _**
- What component meters refrigerant into the evaporator? A. Compressor
B. Condenser C. Expansion valve D. Accumulator _ The expansion device controls refrigerant flow and pressure drop into the evaporator. _**
- What is the primary function of the compressor? A. Cool the refrigerant B. Increase refrigerant pressure C. Store refrigerant D. Filter refrigerant _ The compressor raises pressure and temperature to allow heat rejection in the condenser. _**
- Superheat is measured at which location? A. Liquid line B. Suction line C. Discharge line D. Condenser outlet _ Superheat is the temperature of vapor above saturation at the evaporator outlet/suction line. _**
- What tool measures air velocity? A. Manometer B. Thermocouple C. Anemometer D. Hygrometer _ An anemometer measures air speed, essential for airflow diagnostics. _**
- Low airflow across an evaporator coil will cause: A. High superheat B. Low superheat C. High head pressure D. High subcooling
12.What motor type is most common in PSC blower motors? A. Shaded pole B. Permanent split capacitor C. Universal D. DC series _ PSC motors use a run capacitor for efficiency and smooth operation. ** 13.Which instrument measures pressure difference? A. Manometer B. Voltmeter C. Ohmmeter D. Clamp meter **** Manometers measure static and differential air pressure. ** 14.What condition causes high head pressure? A. Dirty evaporator B. Dirty condenser C. Low ambient D. Low airflow indoor **** Restricted condenser airflow reduces heat rejection, raising head pressure. ** 15.What is the purpose of subcooling? A. Ensure vapor at compressor B. Ensure liquid to metering device C. Prevent icing D. Reduce superheat **** Subcooling confirms a solid column of liquid refrigerant. ** 16.Which gas is added to check for leaks under pressure? A. Oxygen B. Nitrogen C. Carbon dioxide D. Helium **** Dry nitrogen is inert and safe for pressure testing. _**
17.What electrical unit is measured in ohms? A. Resistance B. Voltage C. Current D. Power _ Ohms quantify resistance to electrical flow. ** 18.A TXV controls refrigerant flow based on: A. Subcooling B. Superheat C. Head pressure D. Ambient temperature **** TXVs modulate flow to maintain proper superheat. ** 19.What does an accumulator prevent? A. Overheating B. Liquid refrigerant returning to compressor C. High pressure D. Air contamination **** Accumulators protect compressors from liquid slugging. ** 20.Which meter measures electrical current without opening the circuit? A. Voltmeter B. Clamp meter C. Ohmmeter D. Megohmmeter **** Clamp meters measure current via magnetic field induction. _** 21.What happens to refrigerant pressure as temperature increases? A. Decreases B. Increases C. Stays constant
D. Muffler _ Filter driers protect systems from moisture-related damage. ** 27.What is latent heat? A. Sensible temperature change B. Heat absorbed during phase change C. Electrical heat D. Radiant heat **** Latent heat changes state without changing temperature. ** 28.Which combustion gas is most dangerous? A. Carbon dioxide B. Carbon monoxide C. Nitrogen D. Oxygen **** Carbon monoxide is colorless, odorless, and toxic. ** 29.What does EER measure? A. Seasonal efficiency B. Instantaneous efficiency C. Heating efficiency D. Compressor efficiency **** EER measures efficiency at specific operating conditions. ** 30.What type of heat exchanger is a furnace heat exchanger? A. Shell and tube B. Air-to-air C. Plate D. Water-to-water **** Furnace heat exchangers transfer heat from combustion gases to air. _** 31.Which flame color indicates proper combustion? A. Yellow B. Blue
C. Orange D. Red _ A steady blue flame indicates efficient combustion. ** 32.What causes evaporator icing? A. High airflow B. Low airflow C. High load D. High ambient **** Low airflow reduces heat input, causing coil temperatures to drop below freezing. ** 33.What is the purpose of a contactor? A. Control high-voltage circuits B. Measure current C. Store energy D. Step down voltage **** Contactors safely switch high-voltage loads. ** 34.Which duct material is most flexible? A. Sheet metal B. Flexible duct C. Fiberglass board D. Concrete **** Flexible duct allows easy routing in tight spaces. ** 35.What instrument measures humidity? A. Thermometer B. Hygrometer C. Barometer D. Anemometer **** Hygrometers measure moisture content of air. _** 36.What causes short cycling? A. Dirty filter
41.What is sensible heat? A. Heat that changes temperature B. Heat of vaporization C. Chemical heat D. Electrical heat _ Sensible heat results in measurable temperature change. ** 42.Which refrigerant property absorbs heat in the evaporator? A. Density B. Latent heat C. Color D. Viscosity **** Latent heat enables effective heat absorption during boiling. ** 43.What type of pressure is measured by a vacuum gauge? A. Gauge pressure B. Absolute pressure C. Static pressure D. Differential pressure **** Vacuum gauges reference absolute zero pressure. ** 44.What indicates a restricted liquid line? A. Low subcooling B. High subcooling C. Low head pressure D. Low superheat **** Restrictions back up liquid, increasing subcooling. ** 45.Which system uses both heating and cooling in one unit? A. Heat pump B. Gas furnace C. Boiler D. Chiller **** Heat pumps provide reversible heating and cooling. _**
46.What personal protective equipment is required when brazing? A. Gloves only B. Eye protection C. Ear protection D. Respirator only _ Eye protection prevents injury from sparks and flux. ** 47.What causes compressor overheating? A. Proper airflow B. Low refrigerant charge C. Clean coils D. Correct voltage **** Low charge reduces cooling of the compressor motor. ** 48.What is static pressure? A. Moving air pressure B. Pressure exerted by air at rest C. Electrical pressure D. Liquid pressure **** Static pressure reflects resistance in duct systems. ** 49.What is the primary function of a thermostat? A. Measure humidity B. Control system operation C. Measure pressure D. Control airflow **** Thermostats regulate HVAC operation based on temperature. ** 50.Which code regulates refrigerant handling? A. NEC B. EPA Section 608 C. IMC D. OSHA **** EPA 608 certification is required for refrigerant handling. _**
D. Clamp meter _ Megohmmeters detect insulation breakdown. ** 56.What does CFM measure? A. Airflow volume B. Air pressure C. Air velocity D. Air density **** CFM quantifies cubic feet of air moved per minute. ** 57.What happens when a condenser fan fails? A. Low head pressure B. High head pressure C. Low superheat D. High airflow **** Without airflow, condenser heat rejection stops. ** 58.What is the function of a defrost control? A. Heat the space B. Remove frost from outdoor coil C. Measure humidity D. Control airflow **** Defrost cycles prevent ice buildup on heat pump coils. ** 59.What is the normal superheat range for TXV systems? A. 0–2°F B. 8–12°F C. 20–30°F D. 30–40°F **** TXVs maintain moderate, stable superheat. _** 60.Which material is best for refrigerant lines? A. Aluminum B. Copper C. Steel
D. PVC
_ Copper resists corrosion and handles pressure well. ** 61.What does a float switch protect against? A. Overheating B. Water overflow C. High pressure D. Electrical surge **** Float switches shut systems down when condensate backs up. ** 62.Which device reduces voltage? A. Contactor B. Transformer C. Capacitor D. Relay **** Transformers step down high voltage to control voltage. ** 63.What type of heat transfer occurs through duct walls? A. Conduction B. Convection C. Radiation only D. Compression **** Heat flows through solid materials by conduction. ** 64.What is the function of a plenum? A. Compress air B. Distribute air C. Filter air D. Heat air **** Plenums collect and distribute airflow. _** 65.Which refrigerant property determines saturation temperature? A. Color B. Density
C. Watt D. Ohm _ Watts represent electrical power consumption. ** 71.What causes noisy ductwork? A. Proper sizing B. High static pressure C. Clean filters D. Low airflow **** Excess pressure creates vibration and noise. ** 72.Which heat pump component absorbs heat in winter? A. Outdoor coil B. Indoor coil C. Compressor D. TXV **** The outdoor coil acts as the evaporator in heating mode. ** 73.What is a common symptom of non-condensables in a system? A. Low head pressure B. High head pressure C. Low subcooling D. Low amperage **** Non-condensables occupy condenser space and raise pressure. ** 74.What is the purpose of combustion air? A. Cool equipment B. Support proper burning C. Reduce noise D. Remove exhaust **** Adequate combustion air ensures complete fuel burning. _** 75.What does a zoning system control? A. Refrigerant flow
B. Airflow to different areas C. Compressor speed D. Voltage _ Zoning directs conditioned air where needed. ** 76.What happens if line voltage is too high? A. Motor slows B. Motor overheats C. Pressure drops D. Capacity drops **** Overvoltage stresses motor windings. ** 77.What does a sight glass show? A. Airflow B. Refrigerant condition C. Voltage D. Oil pressure **** Sight glasses indicate liquid refrigerant quality and moisture. ** 78.What is the main advantage of ECM motors? A. Lower airflow B. Energy efficiency C. Higher noise D. Fixed speed **** ECMs adjust speed and reduce energy consumption. ** 79.What is the purpose of a purge unit in chillers? A. Add refrigerant B. Remove non-condensables C. Increase pressure D. Add oil **** Purge units maintain efficiency by removing trapped gases. _** 80.What causes flame rollout? A. Proper draft
85.Which tool is used to flare copper tubing? A. Pipe cutter B. Flaring tool C. Swaging tool D. Bender _ Flaring tools create leak-tight connections. ** 86.What does sensible heat ratio represent? A. Total heat B. Sensible vs total heat C. Latent heat only D. Airflow only **** SHR compares sensible heat to total heat load. ** 87.What is the main cause of corrosion in coils? A. Dry air B. Moisture and contaminants C. High airflow D. Copper purity **** Moisture and chemicals accelerate corrosion. ** 88.Which system uses variable refrigerant flow? A. VRF system B. Split system C. Packaged unit D. Window unit **** VRF systems modulate refrigerant for efficiency. ** 89.What happens when airflow increases across a coil? A. Capacity decreases B. Sensible capacity increases C. Latent increases only D. Pressure rises **** Higher airflow favors sensible heat transfer. _**
90.What is the purpose of a limit switch? A. Control cooling B. Prevent overheating C. Measure voltage D. Increase airflow _ Limit switches shut down equipment at unsafe temperatures. ** 91.What indicates a grounded motor winding? A. Infinite resistance B. Continuity to ground C. Normal amperage D. Correct voltage **** Continuity to ground shows insulation failure. ** 92.Which refrigerant has the highest operating pressure? A. R- 22 B. R-410A C. R-134a D. R- 12 **** R-410A systems operate at significantly higher pressures. ** 93.What is the function of a muffler in refrigeration? A. Reduce heat B. Reduce noise C. Increase pressure D. Store refrigerant **** Mufflers dampen compressor pulsation noise. _** 94.What does negative pressure indicate in a building? A. Air leaking out B. Air being drawn in C. Balanced airflow
