OHIO HVAC CONTRACTOR EXAM PRATICE QUESTIONS
AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025|2026 Q&A | INSTANT DOWNLOAD
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1. What is the primary purpose of a heat exchanger in an HVAC system?
a) To circulate refrigerant
b) To transfer heat between air and refrigerant
c) To filter air
d) To regulate airflow
Answer: b) To transfer heat between air and refrigerant
Explanation: The heat exchanger is responsible for transferring heat between the air and refrigerant,
facilitating the heating or cooling process in HVAC systems.
2. According to the Ohio Mechanical Code, what is the minimum clearance required around a furnace
for proper ventilation?
a) 12 inches
b) 18 inches
c) 24 inches
d) 36 inches
Answer: c) 24 inches
Explanation: The Ohio Mechanical Code mandates a minimum clearance of 24 inches around a furnace
to ensure adequate airflow and safe operation.
3. Which of the following refrigerants is considered ozone-depleting and is being phased out under
the Montreal Protocol?
a) R-22
b) R-410A
c) R-134A
d) R-32
Answer: a) R-22
,Explanation: R-22 is an HCFC refrigerant that contributes to ozone depletion and is being phased out in
favor of more environmentally friendly alternatives.
4. What is the primary function of a thermostat in an HVAC system?
a) To circulate refrigerant
b) To control the temperature by regulating the system's operation
c) To filter air
d) To monitor system pressure
Answer: b) To control the temperature by regulating the system's operation
Explanation: A thermostat senses the ambient temperature and signals the HVAC system to heat or cool
the space to maintain the desired temperature.
5. In Ohio, which agency is responsible for licensing HVAC contractors?
a) Ohio Department of Health
b) Ohio Construction Industry Licensing Board (OCILB)
c) Ohio Environmental Protection Agency
d) Ohio Department of Commerce
Answer: b) Ohio Construction Industry Licensing Board (OCILB)
Explanation: The OCILB oversees the licensing and regulation of HVAC contractors in Ohio, ensuring
compliance with state codes and standards.
6. What is the minimum size of a return air duct in a residential HVAC system?
a) 6 inches
b) 8 inches
c) 10 inches
d) 12 inches
Answer: b) 8 inches
Explanation: An 8-inch return air duct is typically the minimum size recommended for residential systems
to ensure adequate airflow and system efficiency.
7. Which of the following is a common cause of short cycling in an HVAC system?
a) Dirty air filters
b) Oversized equipment
, c) Low refrigerant levels
d) All of the above
Answer: d) All of the above
Explanation: Dirty air filters, oversized equipment, and low refrigerant levels can all cause short cycling,
where the system turns on and off frequently, reducing efficiency and lifespan.
8. What is the purpose of a condensate trap in an HVAC system?
a) To prevent backflow of condensate water
b) To filter air
c) To regulate refrigerant pressure
d) To circulate refrigerant
Answer: a) To prevent backflow of condensate water
Explanation: A condensate trap prevents the backflow of water into the system, ensuring proper
drainage and preventing potential water damage.
9. Which of the following is a requirement for HVAC contractors in Ohio regarding continuing
education?
a) No continuing education is required
b) 8 hours every 2 years
c) 16 hours every 2 years
d) 24 hours every 2 years
Answer: b) 8 hours every 2 years
Explanation: Ohio requires HVAC contractors to complete 8 hours of continuing education every 2 years
to maintain their license.
10. What is the maximum allowable refrigerant charge for a system before it requires a licensed
technician to service?
a) 5 pounds
b) 10 pounds
c) 15 pounds
d) 20 pounds
Answer: b) 10 pounds
Explanation: Systems containing more than 10 pounds of refrigerant must be serviced by a licensed
HVAC technician to comply with EPA regulations.
AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025|2026 Q&A | INSTANT DOWNLOAD
1. What is the primary purpose of a heat exchanger in an HVAC system?
a) To circulate refrigerant
b) To transfer heat between air and refrigerant
c) To filter air
d) To regulate airflow
Answer: b) To transfer heat between air and refrigerant
Explanation: The heat exchanger is responsible for transferring heat between the air and refrigerant,
facilitating the heating or cooling process in HVAC systems.
2. According to the Ohio Mechanical Code, what is the minimum clearance required around a furnace
for proper ventilation?
a) 12 inches
b) 18 inches
c) 24 inches
d) 36 inches
Answer: c) 24 inches
Explanation: The Ohio Mechanical Code mandates a minimum clearance of 24 inches around a furnace
to ensure adequate airflow and safe operation.
3. Which of the following refrigerants is considered ozone-depleting and is being phased out under
the Montreal Protocol?
a) R-22
b) R-410A
c) R-134A
d) R-32
Answer: a) R-22
,Explanation: R-22 is an HCFC refrigerant that contributes to ozone depletion and is being phased out in
favor of more environmentally friendly alternatives.
4. What is the primary function of a thermostat in an HVAC system?
a) To circulate refrigerant
b) To control the temperature by regulating the system's operation
c) To filter air
d) To monitor system pressure
Answer: b) To control the temperature by regulating the system's operation
Explanation: A thermostat senses the ambient temperature and signals the HVAC system to heat or cool
the space to maintain the desired temperature.
5. In Ohio, which agency is responsible for licensing HVAC contractors?
a) Ohio Department of Health
b) Ohio Construction Industry Licensing Board (OCILB)
c) Ohio Environmental Protection Agency
d) Ohio Department of Commerce
Answer: b) Ohio Construction Industry Licensing Board (OCILB)
Explanation: The OCILB oversees the licensing and regulation of HVAC contractors in Ohio, ensuring
compliance with state codes and standards.
6. What is the minimum size of a return air duct in a residential HVAC system?
a) 6 inches
b) 8 inches
c) 10 inches
d) 12 inches
Answer: b) 8 inches
Explanation: An 8-inch return air duct is typically the minimum size recommended for residential systems
to ensure adequate airflow and system efficiency.
7. Which of the following is a common cause of short cycling in an HVAC system?
a) Dirty air filters
b) Oversized equipment
, c) Low refrigerant levels
d) All of the above
Answer: d) All of the above
Explanation: Dirty air filters, oversized equipment, and low refrigerant levels can all cause short cycling,
where the system turns on and off frequently, reducing efficiency and lifespan.
8. What is the purpose of a condensate trap in an HVAC system?
a) To prevent backflow of condensate water
b) To filter air
c) To regulate refrigerant pressure
d) To circulate refrigerant
Answer: a) To prevent backflow of condensate water
Explanation: A condensate trap prevents the backflow of water into the system, ensuring proper
drainage and preventing potential water damage.
9. Which of the following is a requirement for HVAC contractors in Ohio regarding continuing
education?
a) No continuing education is required
b) 8 hours every 2 years
c) 16 hours every 2 years
d) 24 hours every 2 years
Answer: b) 8 hours every 2 years
Explanation: Ohio requires HVAC contractors to complete 8 hours of continuing education every 2 years
to maintain their license.
10. What is the maximum allowable refrigerant charge for a system before it requires a licensed
technician to service?
a) 5 pounds
b) 10 pounds
c) 15 pounds
d) 20 pounds
Answer: b) 10 pounds
Explanation: Systems containing more than 10 pounds of refrigerant must be serviced by a licensed
HVAC technician to comply with EPA regulations.
