HVAC (C-20) CONTRACTOR EXAM | QUESTIONS AND ANSWERS |
VERIFIED ANSWERS PLUS RATIONALES | EXAM ALREADY GRADED A+
| LATEST EXAM UPDATE
1. What is the primary purpose of a heat exchanger in an HVAC system?
A) Filter air
B) Transfer heat between two fluids
C) Increase humidity
D) Reduce air pressure
Answer: B – Transfer heat between two fluids. The heat exchanger allows heat from the
combustion process or another fluid to be transferred to air or water without mixing the two
fluids.
2. What is the typical refrigerant used in residential air conditioning systems today?
A) R-22
B) R-134a
C) R-410A
D) Ammonia
Answer: C – R-410A. R-410A is commonly used in modern residential air conditioning systems
due to its efficiency and compliance with phase-out regulations of older refrigerants like R-22.
3. In HVAC systems, what does SEER stand for?
A) Seasonal Energy Efficiency Ratio
B) Standard Electrical Efficiency Rating
C) Seasonal Energy Exhaust Rate
D) System Efficiency Evaluation Ratio
Answer: A – Seasonal Energy Efficiency Ratio. SEER measures the cooling efficiency of air
conditioners over a typical cooling season.
4. Which component of an HVAC system is responsible for moving air through ductwork?
A) Condenser
B) Evaporator coil
C) Blower fan
D) Thermostat
Answer: C – Blower fan. The blower fan circulates conditioned air throughout the duct system to
maintain indoor comfort.
5. What is the minimum clearance required around a gas furnace for service access?
A) 1 inch
, B) 6 inches
C) 18 inches
D) 36 inches
Answer: C – 18 inches. Most codes require at least 18 inches of clearance in front of a gas
furnace for proper maintenance and service.
6. A split HVAC system is defined as:
A) A system that heats and cools simultaneously
B) A system with components both inside and outside the building
C) A system that uses natural ventilation
D) A system powered by renewable energy
Answer: B – A system with components both inside and outside the building. Split systems have
an indoor evaporator coil and an outdoor condenser.
7. What is the purpose of a thermostat in an HVAC system?
A) To control refrigerant flow
B) To regulate temperature
C) To move air
D) To filter dust
Answer: B – To regulate temperature. The thermostat senses the temperature and controls the
operation of heating or cooling equipment to maintain the desired setpoint.
8. What is the typical pressure of a residential natural gas system?
A) 0.25 psi
B) 5 psi
C) 10 psi
D) 50 psi
Answer: A – 0.25 psi. Residential natural gas lines operate at very low pressure, usually around
0.25 psi or 7 inches water column.
9. Which HVAC component removes moisture from the air?
A) Condenser
B) Evaporator coil
C) Expansion valve
D) Compressor
Answer: B – Evaporator coil. The evaporator coil cools the air, causing moisture to condense
and drain away, effectively dehumidifying the air.
10. What type of maintenance is recommended for HVAC systems annually?
A) Change filters monthly
B) Clean ducts once a decade
VERIFIED ANSWERS PLUS RATIONALES | EXAM ALREADY GRADED A+
| LATEST EXAM UPDATE
1. What is the primary purpose of a heat exchanger in an HVAC system?
A) Filter air
B) Transfer heat between two fluids
C) Increase humidity
D) Reduce air pressure
Answer: B – Transfer heat between two fluids. The heat exchanger allows heat from the
combustion process or another fluid to be transferred to air or water without mixing the two
fluids.
2. What is the typical refrigerant used in residential air conditioning systems today?
A) R-22
B) R-134a
C) R-410A
D) Ammonia
Answer: C – R-410A. R-410A is commonly used in modern residential air conditioning systems
due to its efficiency and compliance with phase-out regulations of older refrigerants like R-22.
3. In HVAC systems, what does SEER stand for?
A) Seasonal Energy Efficiency Ratio
B) Standard Electrical Efficiency Rating
C) Seasonal Energy Exhaust Rate
D) System Efficiency Evaluation Ratio
Answer: A – Seasonal Energy Efficiency Ratio. SEER measures the cooling efficiency of air
conditioners over a typical cooling season.
4. Which component of an HVAC system is responsible for moving air through ductwork?
A) Condenser
B) Evaporator coil
C) Blower fan
D) Thermostat
Answer: C – Blower fan. The blower fan circulates conditioned air throughout the duct system to
maintain indoor comfort.
5. What is the minimum clearance required around a gas furnace for service access?
A) 1 inch
, B) 6 inches
C) 18 inches
D) 36 inches
Answer: C – 18 inches. Most codes require at least 18 inches of clearance in front of a gas
furnace for proper maintenance and service.
6. A split HVAC system is defined as:
A) A system that heats and cools simultaneously
B) A system with components both inside and outside the building
C) A system that uses natural ventilation
D) A system powered by renewable energy
Answer: B – A system with components both inside and outside the building. Split systems have
an indoor evaporator coil and an outdoor condenser.
7. What is the purpose of a thermostat in an HVAC system?
A) To control refrigerant flow
B) To regulate temperature
C) To move air
D) To filter dust
Answer: B – To regulate temperature. The thermostat senses the temperature and controls the
operation of heating or cooling equipment to maintain the desired setpoint.
8. What is the typical pressure of a residential natural gas system?
A) 0.25 psi
B) 5 psi
C) 10 psi
D) 50 psi
Answer: A – 0.25 psi. Residential natural gas lines operate at very low pressure, usually around
0.25 psi or 7 inches water column.
9. Which HVAC component removes moisture from the air?
A) Condenser
B) Evaporator coil
C) Expansion valve
D) Compressor
Answer: B – Evaporator coil. The evaporator coil cools the air, causing moisture to condense
and drain away, effectively dehumidifying the air.
10. What type of maintenance is recommended for HVAC systems annually?
A) Change filters monthly
B) Clean ducts once a decade
