1. What is the primary function of a hydronic heating system?
A. To cool indoor air
B. To distribute heat using water or steam
C. To generate electricity
D. To control humidity
Answer: B – Hydronic systems use heated water or steam circulated through
piping to distribute heat efficiently.
2. In Ohio, a contractor license for hydronics is regulated by which state board?
A. Ohio Board of Building Standards
B. Ohio Construction Industry Licensing Board (OCILB)
C. Ohio Department of Labor
D. Public Utilities Commission of Ohio
Answer: B – The OCILB regulates mechanical contractor licenses including
hydronics.
3. What is the minimum operating pressure for a low-pressure steam boiler?
A. 5 psi
B. 15 psi
C. 30 psi
D. 50 psi
Answer: B – Low-pressure steam boilers are defined as operating at or below
15 psi.
4. Which piping material is most commonly used for hydronic heating systems?
A. PVC
B. CPVC
C. Copper
D. Galvanized steel
Answer: C – Copper is widely used because of its durability and heat transfer
properties.
5. What is the main advantage of a closed-loop hydronic system?
A. Eliminates oxygen corrosion
B. Requires no expansion tank
,C. Uses outdoor air for circulation
D. Operates without a pump
Answer: A – Closed loops reduce oxygen infiltration, which minimizes
corrosion.
6. What device removes air from hydronic systems?
A. Pressure reducing valve
B. Flow control valve
C. Air separator
D. Zone valve
Answer: C – Air separators or air vents release trapped air to maintain system
efficiency.
7. A backflow preventer is required in hydronic systems to:
A. Increase water temperature
B. Prevent contamination of potable water supply
C. Regulate system pressure
D. Control water hammer
Answer: B – It ensures boiler water cannot contaminate potable supply.
8. What is the purpose of an expansion tank in a hydronic system?
A. Store excess hot water
B. Absorb thermal expansion of water
C. Remove sediment
D. Act as a mixing chamber
Answer: B – It prevents excessive system pressure caused by water expansion.
9. The unit of measure for heat energy in hydronic heating is:
A. Ampere
B. Joule
C. BTU
D. Watt
Answer: C – BTU (British Thermal Unit) is the standard measure in heating
applications.
10. In Ohio, what is the minimum liability insurance coverage required for
hydronics contractors?
A. $50,000
B. $100,000
C. $300,000
D. $500,000
Answer: C – Contractors must carry at least $300,000 liability insurance.
,11. Which hydronic system uses both heating and cooling distribution?
A. One-pipe system
B. Dual-temperature system
C. Gravity system
D. Monoflow system
Answer: B – Dual-temp systems supply both heated and chilled water.
12. A circulator pump in a hydronic system functions to:
A. Increase boiler efficiency
B. Move water through piping loops
C. Store heated water
D. Remove air from system
Answer: B – Pumps keep water circulating for even heat distribution.
13. Which code primarily governs hydronic system installation in Ohio?
A. International Mechanical Code (IMC)
B. National Electrical Code (NEC)
C. Ohio Revised Code (ORC) 4740
D. Uniform Plumbing Code (UPC)
Answer: A – Ohio adopts the IMC as part of its building standards.
14. What does "head" measure in hydronic systems?
A. Temperature of water
B. Flow velocity
C. Pressure required to move water
D. Boiler capacity
Answer: C – Head is the pressure a pump must overcome to circulate water.
15. A zone valve is controlled by:
A. Boiler aquastat
B. Thermostat
C. Expansion tank
D. Relief valve
Answer: B – Zone valves open/close based on thermostat signals.
16. Which safety device protects a boiler from excessive pressure?
A. Aquastat
B. Relief valve
C. Backflow preventer
D. Pressure gauge
Answer: B – Relief valves release water/steam if pressure exceeds safe levels.
17. What is the typical maximum water temperature in residential hydronic
systems?
, A. 140°F
B. 160°F
C. 180°F
D. 212°F
Answer: C – Most operate with 180°F supply water.
18. In Ohio, a hydronics contractor license must be renewed every:
A. 1 year
B. 2 years
C. 3 years
D. 5 years
Answer: B – Renewal occurs every 2 years.
19. What type of heat emitter is most common in hydronic systems?
A. Air ducts
B. Radiators
C. Baseboard convectors
D. Heat pumps
Answer: C – Baseboard fin-tube convectors are common in modern systems.
20. Which boiler component controls burner operation based on water
temperature?
A. Thermostat
B. Aquastat
C. Circulator pump
D. Flow switch
Answer: B – The aquastat monitors water temp and signals burner.
21. Which hydronic piping layout provides the most balanced heat distribution?
A. One-pipe
B. Two-pipe direct return
C. Two-pipe reverse return
D. Monoflow
Answer: C – Reverse return ensures even flow to all radiators.
22. What is the primary cause of cavitation in a hydronic pump?
A. Low water temperature
B. Excessive pressure
C. Insufficient net positive suction head (NPSH)
D. High altitude
Answer: C – Cavitation occurs when pressure drops below vapor pressure of
water.
A. To cool indoor air
B. To distribute heat using water or steam
C. To generate electricity
D. To control humidity
Answer: B – Hydronic systems use heated water or steam circulated through
piping to distribute heat efficiently.
2. In Ohio, a contractor license for hydronics is regulated by which state board?
A. Ohio Board of Building Standards
B. Ohio Construction Industry Licensing Board (OCILB)
C. Ohio Department of Labor
D. Public Utilities Commission of Ohio
Answer: B – The OCILB regulates mechanical contractor licenses including
hydronics.
3. What is the minimum operating pressure for a low-pressure steam boiler?
A. 5 psi
B. 15 psi
C. 30 psi
D. 50 psi
Answer: B – Low-pressure steam boilers are defined as operating at or below
15 psi.
4. Which piping material is most commonly used for hydronic heating systems?
A. PVC
B. CPVC
C. Copper
D. Galvanized steel
Answer: C – Copper is widely used because of its durability and heat transfer
properties.
5. What is the main advantage of a closed-loop hydronic system?
A. Eliminates oxygen corrosion
B. Requires no expansion tank
,C. Uses outdoor air for circulation
D. Operates without a pump
Answer: A – Closed loops reduce oxygen infiltration, which minimizes
corrosion.
6. What device removes air from hydronic systems?
A. Pressure reducing valve
B. Flow control valve
C. Air separator
D. Zone valve
Answer: C – Air separators or air vents release trapped air to maintain system
efficiency.
7. A backflow preventer is required in hydronic systems to:
A. Increase water temperature
B. Prevent contamination of potable water supply
C. Regulate system pressure
D. Control water hammer
Answer: B – It ensures boiler water cannot contaminate potable supply.
8. What is the purpose of an expansion tank in a hydronic system?
A. Store excess hot water
B. Absorb thermal expansion of water
C. Remove sediment
D. Act as a mixing chamber
Answer: B – It prevents excessive system pressure caused by water expansion.
9. The unit of measure for heat energy in hydronic heating is:
A. Ampere
B. Joule
C. BTU
D. Watt
Answer: C – BTU (British Thermal Unit) is the standard measure in heating
applications.
10. In Ohio, what is the minimum liability insurance coverage required for
hydronics contractors?
A. $50,000
B. $100,000
C. $300,000
D. $500,000
Answer: C – Contractors must carry at least $300,000 liability insurance.
,11. Which hydronic system uses both heating and cooling distribution?
A. One-pipe system
B. Dual-temperature system
C. Gravity system
D. Monoflow system
Answer: B – Dual-temp systems supply both heated and chilled water.
12. A circulator pump in a hydronic system functions to:
A. Increase boiler efficiency
B. Move water through piping loops
C. Store heated water
D. Remove air from system
Answer: B – Pumps keep water circulating for even heat distribution.
13. Which code primarily governs hydronic system installation in Ohio?
A. International Mechanical Code (IMC)
B. National Electrical Code (NEC)
C. Ohio Revised Code (ORC) 4740
D. Uniform Plumbing Code (UPC)
Answer: A – Ohio adopts the IMC as part of its building standards.
14. What does "head" measure in hydronic systems?
A. Temperature of water
B. Flow velocity
C. Pressure required to move water
D. Boiler capacity
Answer: C – Head is the pressure a pump must overcome to circulate water.
15. A zone valve is controlled by:
A. Boiler aquastat
B. Thermostat
C. Expansion tank
D. Relief valve
Answer: B – Zone valves open/close based on thermostat signals.
16. Which safety device protects a boiler from excessive pressure?
A. Aquastat
B. Relief valve
C. Backflow preventer
D. Pressure gauge
Answer: B – Relief valves release water/steam if pressure exceeds safe levels.
17. What is the typical maximum water temperature in residential hydronic
systems?
, A. 140°F
B. 160°F
C. 180°F
D. 212°F
Answer: C – Most operate with 180°F supply water.
18. In Ohio, a hydronics contractor license must be renewed every:
A. 1 year
B. 2 years
C. 3 years
D. 5 years
Answer: B – Renewal occurs every 2 years.
19. What type of heat emitter is most common in hydronic systems?
A. Air ducts
B. Radiators
C. Baseboard convectors
D. Heat pumps
Answer: C – Baseboard fin-tube convectors are common in modern systems.
20. Which boiler component controls burner operation based on water
temperature?
A. Thermostat
B. Aquastat
C. Circulator pump
D. Flow switch
Answer: B – The aquastat monitors water temp and signals burner.
21. Which hydronic piping layout provides the most balanced heat distribution?
A. One-pipe
B. Two-pipe direct return
C. Two-pipe reverse return
D. Monoflow
Answer: C – Reverse return ensures even flow to all radiators.
22. What is the primary cause of cavitation in a hydronic pump?
A. Low water temperature
B. Excessive pressure
C. Insufficient net positive suction head (NPSH)
D. High altitude
Answer: C – Cavitation occurs when pressure drops below vapor pressure of
water.
