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Michigan (MI) Hydronic Heating, Cooling & Process
Piping exam Questions with Correct Answers and
explanations LATEST THIS YEAR -JUST RELEASED
Below is a summarized exam coverage for the Michigan Hydronic Heating, Cooling & Process Piping
Exam, followed by 200 randomized, scenario-based MCQs directly aligned with the exam. No subtopics
or domain headings are used—just questions, answers, and concise rationales. Questions are based on
the Michigan Mechanical Code (adopting IMC with amendments), ASME B31.9 (Building Services Piping),
ASME B31.5 (Refrigeration Piping), ASME B31.1 (Power Piping for process), hydronic heating/cooling
principles, piping materials, expansion and contraction, pump selection, heat exchanger sizing, water
treatment, safety (pressure vessels, relief valves, lockout/tagout), and Michigan licensing requirements.
1. A Michigan hydronic heating system is designed for a maximum operating temperature of 200°F.
According to ASME B31.9, the minimum pressure rating for the piping is:
A) 100 psi
B) 125 psi
C) 150 psi
D) 200 psi
Answer: C – ASME B31.9 requires piping rated for at least 150 psi for systems up to 200°F.
2. A contractor is installing a closed-loop hydronic system. The expansion tank must be located on the:
A) Suction side of the pump
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B) Discharge side of the pump
C) At the highest point of the system
D) At the lowest point of the system
Answer: A – Expansion tank should be on the pump suction side to minimize pressure fluctuations.
3. A hydronic piping system uses black steel pipe. The pipe must be protected from corrosion by:
A) Using dielectric unions when connecting to dissimilar metals
B) Painting the exterior
C) Wrapping with tape
D) No protection needed
Answer: A – Dielectric unions prevent galvanic corrosion between steel and copper or brass.
4. A process piping system carries hot water at 180°F. The pipe material is copper. The maximum
allowable stress for copper at this temperature per ASME B31.9 is reduced compared to room
temperature. The de-rating factor is approximately:
A) 0.85
B) 0.90
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C) 0.95
D) 1.00
Answer: A – Copper strength decreases above 150°F; typical de-rating factor 0.85 at 180°F.
5. A Michigan hydronic heating contractor must hold a license. Which license classification is required
for hydronic heating and cooling piping?
A) Mechanical Contractor
B) Plumbing Contractor
C) Hydronic Heating Specialist
D) Refrigeration Contractor
Answer: A – Hydronic piping falls under the Mechanical Contractor license in Michigan.
6. A chilled water system has a closed expansion tank. The tank is pressurized with nitrogen. The initial
charge pressure should be set at:
A) The static pressure at the tank location plus 5 psi
B) The pump shutoff head
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C) 0 psi
D) The system relief valve setting
Answer: A – Tank pre-charge equals static pressure at tank location plus a small margin to prevent
cavitation.
7. A process piping system uses carbon steel pipe. The pipe is 4 inches in diameter and carries steam at
150 psig. The required wall thickness per ASME B31.1 is calculated using which formula?
A) Barlow’s formula
B) Manning’s equation
C) Darcy-Weisbach
D) Hazen-Williams
Answer: A – *Barlow’s formula (P = 2St/D) relates pressure, stress, thickness, and diameter.*
8. A hydronic heating system has a boiler with a relief valve set at 30 psi. The expansion tank pre-charge
should be set at:
A) 10 psi
B) 15 psi
Michigan (MI) Hydronic Heating, Cooling & Process
Piping exam Questions with Correct Answers and
explanations LATEST THIS YEAR -JUST RELEASED
Below is a summarized exam coverage for the Michigan Hydronic Heating, Cooling & Process Piping
Exam, followed by 200 randomized, scenario-based MCQs directly aligned with the exam. No subtopics
or domain headings are used—just questions, answers, and concise rationales. Questions are based on
the Michigan Mechanical Code (adopting IMC with amendments), ASME B31.9 (Building Services Piping),
ASME B31.5 (Refrigeration Piping), ASME B31.1 (Power Piping for process), hydronic heating/cooling
principles, piping materials, expansion and contraction, pump selection, heat exchanger sizing, water
treatment, safety (pressure vessels, relief valves, lockout/tagout), and Michigan licensing requirements.
1. A Michigan hydronic heating system is designed for a maximum operating temperature of 200°F.
According to ASME B31.9, the minimum pressure rating for the piping is:
A) 100 psi
B) 125 psi
C) 150 psi
D) 200 psi
Answer: C – ASME B31.9 requires piping rated for at least 150 psi for systems up to 200°F.
2. A contractor is installing a closed-loop hydronic system. The expansion tank must be located on the:
A) Suction side of the pump
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B) Discharge side of the pump
C) At the highest point of the system
D) At the lowest point of the system
Answer: A – Expansion tank should be on the pump suction side to minimize pressure fluctuations.
3. A hydronic piping system uses black steel pipe. The pipe must be protected from corrosion by:
A) Using dielectric unions when connecting to dissimilar metals
B) Painting the exterior
C) Wrapping with tape
D) No protection needed
Answer: A – Dielectric unions prevent galvanic corrosion between steel and copper or brass.
4. A process piping system carries hot water at 180°F. The pipe material is copper. The maximum
allowable stress for copper at this temperature per ASME B31.9 is reduced compared to room
temperature. The de-rating factor is approximately:
A) 0.85
B) 0.90
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C) 0.95
D) 1.00
Answer: A – Copper strength decreases above 150°F; typical de-rating factor 0.85 at 180°F.
5. A Michigan hydronic heating contractor must hold a license. Which license classification is required
for hydronic heating and cooling piping?
A) Mechanical Contractor
B) Plumbing Contractor
C) Hydronic Heating Specialist
D) Refrigeration Contractor
Answer: A – Hydronic piping falls under the Mechanical Contractor license in Michigan.
6. A chilled water system has a closed expansion tank. The tank is pressurized with nitrogen. The initial
charge pressure should be set at:
A) The static pressure at the tank location plus 5 psi
B) The pump shutoff head
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C) 0 psi
D) The system relief valve setting
Answer: A – Tank pre-charge equals static pressure at tank location plus a small margin to prevent
cavitation.
7. A process piping system uses carbon steel pipe. The pipe is 4 inches in diameter and carries steam at
150 psig. The required wall thickness per ASME B31.1 is calculated using which formula?
A) Barlow’s formula
B) Manning’s equation
C) Darcy-Weisbach
D) Hazen-Williams
Answer: A – *Barlow’s formula (P = 2St/D) relates pressure, stress, thickness, and diameter.*
8. A hydronic heating system has a boiler with a relief valve set at 30 psi. The expansion tank pre-charge
should be set at:
A) 10 psi
B) 15 psi
