Ohio (OH) Hydronics Contractor Practice
Exam | 2025/2026 | Questions and answers |
Instant Download!!
1. Hydronic heating systems primarily use which medium to transfer heat?
A. Air
B. Steam only
C. Water or water-based solutions (Correct Answer)
D. Refrigerant gas
Rationale:
Hydronic systems circulate water or a water-glycol mixture to transfer heat efficiently.
2. Which component is responsible for moving water through a hydronic system?
A. Expansion tank
B. Heat exchanger
C. Circulator pump (Correct Answer)
D. Pressure relief valve
Rationale:
The circulator pump provides the force needed to move heated water through piping and
emitters.
3. In Ohio, hydronics contractor licensing requirements are typically
administered by:
A. U.S. Department of Energy
B. Local fire departments
C. State or local building authorities (Correct Answer)
D. Environmental Protection Agency
Rationale:
Ohio contractor licensing and enforcement are handled at the state and local jurisdiction level.
,4. What is the primary purpose of an expansion tank?
A. Increase system temperature
B. Remove air from piping
C. Absorb thermal expansion of water (Correct Answer)
D. Filter debris
Rationale:
As water heats, it expands; the expansion tank prevents dangerous pressure buildup.
5. A pressure relief valve in a hydronic system is REQUIRED to:
A. Improve system efficiency
B. Reduce noise
C. Prevent excessive pressure buildup (Correct Answer)
D. Increase flow rate
Rationale:
Pressure relief valves protect the system from overpressure conditions that could cause failure.
6. Which type of boiler is MOST efficient for residential hydronic heating?
A. Atmospheric boiler
B. Oil-fired boiler
C. Condensing boiler (Correct Answer)
D. Gravity boiler
Rationale:
Condensing boilers recover latent heat from exhaust gases, increasing efficiency.
7. What is the primary function of a heat exchanger?
A. Circulate water
B. Store hot water
C. Transfer heat between fluids (Correct Answer)
D. Control pressure
Rationale:
Heat exchangers allow heat transfer without mixing different fluids.
,8. Which piping material is commonly used in modern hydronic systems?
A. Galvanized steel
B. Cast iron
C. PEX tubing (Correct Answer)
D. Aluminum conduit
Rationale:
PEX is flexible, corrosion-resistant, and widely used in hydronic applications.
9. A hydronic system that supplies both heating and domestic hot water is known
as:
A. Closed-loop system
B. Open-loop system
C. Combination (combi) system (Correct Answer)
D. Zoned-only system
Rationale:
Combi systems serve both space heating and domestic hot water needs.
10. Which control device regulates water temperature leaving the boiler?
A. Air separator
B. Aquastat (Correct Answer)
C. Backflow preventer
D. Flow switch
Rationale:
Aquastats monitor and control boiler water temperature.
11. What is zoning in hydronic systems primarily used for?
A. Increasing boiler size
B. Reducing piping length
C. Providing independent temperature control (Correct Answer)
D. Eliminating circulators
, Rationale:
Zoning allows different areas to be heated independently for comfort and efficiency.
12. Which device prevents reverse flow in a hydronic system?
A. Air vent
B. Expansion tank
C. Check valve (Correct Answer)
D. Pressure gauge
Rationale:
Check valves ensure water flows in only one direction.
13. The MOST common cause of air noise in hydronic piping is:
A. Oversized boiler
B. Entrapped air in the system (Correct Answer)
C. High water temperature
D. Incorrect thermostat
Rationale:
Air trapped in piping causes gurgling and flow issues.
14. What is the typical operating pressure range for residential hydronic
systems?
A. 1–5 psi
B. 12–20 psi (Correct Answer)
C. 40–60 psi
D. Over 100 psi
Rationale:
Most residential systems operate safely between 12 and 20 psi.
15. A mixing valve is primarily used to:
Exam | 2025/2026 | Questions and answers |
Instant Download!!
1. Hydronic heating systems primarily use which medium to transfer heat?
A. Air
B. Steam only
C. Water or water-based solutions (Correct Answer)
D. Refrigerant gas
Rationale:
Hydronic systems circulate water or a water-glycol mixture to transfer heat efficiently.
2. Which component is responsible for moving water through a hydronic system?
A. Expansion tank
B. Heat exchanger
C. Circulator pump (Correct Answer)
D. Pressure relief valve
Rationale:
The circulator pump provides the force needed to move heated water through piping and
emitters.
3. In Ohio, hydronics contractor licensing requirements are typically
administered by:
A. U.S. Department of Energy
B. Local fire departments
C. State or local building authorities (Correct Answer)
D. Environmental Protection Agency
Rationale:
Ohio contractor licensing and enforcement are handled at the state and local jurisdiction level.
,4. What is the primary purpose of an expansion tank?
A. Increase system temperature
B. Remove air from piping
C. Absorb thermal expansion of water (Correct Answer)
D. Filter debris
Rationale:
As water heats, it expands; the expansion tank prevents dangerous pressure buildup.
5. A pressure relief valve in a hydronic system is REQUIRED to:
A. Improve system efficiency
B. Reduce noise
C. Prevent excessive pressure buildup (Correct Answer)
D. Increase flow rate
Rationale:
Pressure relief valves protect the system from overpressure conditions that could cause failure.
6. Which type of boiler is MOST efficient for residential hydronic heating?
A. Atmospheric boiler
B. Oil-fired boiler
C. Condensing boiler (Correct Answer)
D. Gravity boiler
Rationale:
Condensing boilers recover latent heat from exhaust gases, increasing efficiency.
7. What is the primary function of a heat exchanger?
A. Circulate water
B. Store hot water
C. Transfer heat between fluids (Correct Answer)
D. Control pressure
Rationale:
Heat exchangers allow heat transfer without mixing different fluids.
,8. Which piping material is commonly used in modern hydronic systems?
A. Galvanized steel
B. Cast iron
C. PEX tubing (Correct Answer)
D. Aluminum conduit
Rationale:
PEX is flexible, corrosion-resistant, and widely used in hydronic applications.
9. A hydronic system that supplies both heating and domestic hot water is known
as:
A. Closed-loop system
B. Open-loop system
C. Combination (combi) system (Correct Answer)
D. Zoned-only system
Rationale:
Combi systems serve both space heating and domestic hot water needs.
10. Which control device regulates water temperature leaving the boiler?
A. Air separator
B. Aquastat (Correct Answer)
C. Backflow preventer
D. Flow switch
Rationale:
Aquastats monitor and control boiler water temperature.
11. What is zoning in hydronic systems primarily used for?
A. Increasing boiler size
B. Reducing piping length
C. Providing independent temperature control (Correct Answer)
D. Eliminating circulators
, Rationale:
Zoning allows different areas to be heated independently for comfort and efficiency.
12. Which device prevents reverse flow in a hydronic system?
A. Air vent
B. Expansion tank
C. Check valve (Correct Answer)
D. Pressure gauge
Rationale:
Check valves ensure water flows in only one direction.
13. The MOST common cause of air noise in hydronic piping is:
A. Oversized boiler
B. Entrapped air in the system (Correct Answer)
C. High water temperature
D. Incorrect thermostat
Rationale:
Air trapped in piping causes gurgling and flow issues.
14. What is the typical operating pressure range for residential hydronic
systems?
A. 1–5 psi
B. 12–20 psi (Correct Answer)
C. 40–60 psi
D. Over 100 psi
Rationale:
Most residential systems operate safely between 12 and 20 psi.
15. A mixing valve is primarily used to:
