OHIO HYDRONICS CONTRACTOR PRACTICE
EXAM 2026 EXAMPREP STUDY GUIDE WITH
COMPLETE Q&A
◉ What is required on an up-fed system but not on a down-fed
system? Answer: An air vent.
◉ What is required when a conventional boiler is installed in a low
temperature radiant floor heating application? Answer: A mixing
valve.
◉ What is the purpose of a three or four way mixing valve in a
hydronic heating system? Answer: Mixes the water from the heat
source ad the system return in order to temper system supply water.
◉ What is the minimum pressure test on tubing for radiant floor
heating? Answer: The greater of either 60 PSI or 1.5 times the
working pressure for 1 hour with no pressure drop.
◉ In a hydronic heating system, it is critical that the circulator pump
be installed in what position? Answer: Horizontal
,◉ The fan in a _____ unit heater is located ahead of the coil pulling air
through the coils. Answer: Draw through unit heater.
◉ When activated, the low water cut-off on an automatically fired
hot water heating boiler will cut off the? Answer: Fuel supply to the
boiler.
◉ What is the device called that regulates the pressure on a low
pressure boiler ? Answer: Pressure reducing valve.
◉ A zone valve which opens when the power is on and closes when
power is taken away is known as? Answer: Normally closed.
◉ The difference in temperature between the supply and return
lines in a heating system are known as? Answer: Differential
temperature.
◉ Why are most condensing boilers constructed of stainless steel ?
Answer: Because of the high condensate rate of the boiler.
◉ What is the purpose of the high limit switch ? Answer: To protect
the boiler from overheating. It acts as a safety switch and cuts of the
fuel supply if overheated.
, ◉ What kind of acid is found in condensate from a boiler? Answer:
Sulfuric acid.
◉ What should be installed to seperate the boiler water and the
system water when glycol is added to the water in a radiant floor
heating system? Answer: A plate heat exchanger
◉ What must be installed with a three or four way mixing valve in
order to protect the heat source and the radiant floor system?
Answer: A drive motor and controller.
◉ What is required when piping a low mass boiler that is flow
sensitive? Answer: A bypass pump between the supply and return
piping.
◉ What can affect the way a house is zoned? Answer: North and
South exposures.
◉ What 3 things must you know to properly size tubing for an
application? Answer: Gallons per minute, Velocity and length of the
circuit.
◉ Why are heat exchangers typically installed? Answer: To separate
two liquids.
EXAM 2026 EXAMPREP STUDY GUIDE WITH
COMPLETE Q&A
◉ What is required on an up-fed system but not on a down-fed
system? Answer: An air vent.
◉ What is required when a conventional boiler is installed in a low
temperature radiant floor heating application? Answer: A mixing
valve.
◉ What is the purpose of a three or four way mixing valve in a
hydronic heating system? Answer: Mixes the water from the heat
source ad the system return in order to temper system supply water.
◉ What is the minimum pressure test on tubing for radiant floor
heating? Answer: The greater of either 60 PSI or 1.5 times the
working pressure for 1 hour with no pressure drop.
◉ In a hydronic heating system, it is critical that the circulator pump
be installed in what position? Answer: Horizontal
,◉ The fan in a _____ unit heater is located ahead of the coil pulling air
through the coils. Answer: Draw through unit heater.
◉ When activated, the low water cut-off on an automatically fired
hot water heating boiler will cut off the? Answer: Fuel supply to the
boiler.
◉ What is the device called that regulates the pressure on a low
pressure boiler ? Answer: Pressure reducing valve.
◉ A zone valve which opens when the power is on and closes when
power is taken away is known as? Answer: Normally closed.
◉ The difference in temperature between the supply and return
lines in a heating system are known as? Answer: Differential
temperature.
◉ Why are most condensing boilers constructed of stainless steel ?
Answer: Because of the high condensate rate of the boiler.
◉ What is the purpose of the high limit switch ? Answer: To protect
the boiler from overheating. It acts as a safety switch and cuts of the
fuel supply if overheated.
, ◉ What kind of acid is found in condensate from a boiler? Answer:
Sulfuric acid.
◉ What should be installed to seperate the boiler water and the
system water when glycol is added to the water in a radiant floor
heating system? Answer: A plate heat exchanger
◉ What must be installed with a three or four way mixing valve in
order to protect the heat source and the radiant floor system?
Answer: A drive motor and controller.
◉ What is required when piping a low mass boiler that is flow
sensitive? Answer: A bypass pump between the supply and return
piping.
◉ What can affect the way a house is zoned? Answer: North and
South exposures.
◉ What 3 things must you know to properly size tubing for an
application? Answer: Gallons per minute, Velocity and length of the
circuit.
◉ Why are heat exchangers typically installed? Answer: To separate
two liquids.
