Minnesota Restricted Master Plumber
Examination Questions and Correct
Answers (Verified Answers) Plus Rationale
2027 Q&A| Instant Download Pdf
1. Which responsibility is most directly associated with a master
plumber?
A. Performing only unlicensed plumbing work
B. Supervising and directing plumbing work in accordance with
applicable requirements
C. Inspecting electrical installations
D. Issuing building permits
Answer: B. Supervising and directing plumbing work in accordance
with applicable requirements
Rationale: A master plumber is qualified to take responsibility for
plumbing work and, where permitted by the applicable licensing
structure, supervise plumbing activities. The role carries greater
,responsibility than that of an individual worker performing plumbing
tasks under supervision.
2. What is the primary purpose of a plumbing trap?
A. Increase water pressure
B. Prevent sewer gases from entering a building
C. Increase drainage velocity
D. Prevent hot water from entering fixtures
Answer: B. Prevent sewer gases from entering a building
Rationale: A plumbing trap retains a water seal between the drainage
system and the occupied space. This water seal helps prevent sewer
gases and odors from entering the building through fixture drains.
3. Which fitting is commonly used to change the direction of a
drainage pipe?
A. Elbow
B. Coupling
C. Union
D. Bushing
,Answer: A. Elbow
Rationale: Elbows are designed to change the direction of piping. In
drainage systems, fittings must be selected and installed so that they
provide proper flow and minimize the potential for obstruction.
4. What is the main purpose of a cleanout in a drainage system?
A. Increase water temperature
B. Provide access for cleaning and servicing the drainage piping
C. Reduce water pressure
D. Prevent fixture siphonage
Answer: B. Provide access for cleaning and servicing the drainage
piping
Rationale: Cleanouts provide access to drainage piping so blockages
can be removed and the piping can be inspected or maintained. Their
location and accessibility are important for effective system
maintenance.
5. What is the primary function of a venting system in a plumbing
drainage system?
, A. Supply drinking water
B. Maintain proper drainage-system air pressure and protect trap seals
C. Increase water heater capacity
D. Filter wastewater
Answer: B. Maintain proper drainage-system air pressure and protect
trap seals
Rationale: Proper venting allows air to enter and leave the drainage
system, helping maintain balanced pressures. This reduces the
possibility of trap seal loss caused by siphonage or pressure
fluctuations.
6. A fixture trap that loses its water seal because wastewater flowing
through a drain creates negative pressure is experiencing:
A. Backpressure
B. Siphonage
C. Thermal expansion
D. Water hammer
Answer: B. Siphonage
Examination Questions and Correct
Answers (Verified Answers) Plus Rationale
2027 Q&A| Instant Download Pdf
1. Which responsibility is most directly associated with a master
plumber?
A. Performing only unlicensed plumbing work
B. Supervising and directing plumbing work in accordance with
applicable requirements
C. Inspecting electrical installations
D. Issuing building permits
Answer: B. Supervising and directing plumbing work in accordance
with applicable requirements
Rationale: A master plumber is qualified to take responsibility for
plumbing work and, where permitted by the applicable licensing
structure, supervise plumbing activities. The role carries greater
,responsibility than that of an individual worker performing plumbing
tasks under supervision.
2. What is the primary purpose of a plumbing trap?
A. Increase water pressure
B. Prevent sewer gases from entering a building
C. Increase drainage velocity
D. Prevent hot water from entering fixtures
Answer: B. Prevent sewer gases from entering a building
Rationale: A plumbing trap retains a water seal between the drainage
system and the occupied space. This water seal helps prevent sewer
gases and odors from entering the building through fixture drains.
3. Which fitting is commonly used to change the direction of a
drainage pipe?
A. Elbow
B. Coupling
C. Union
D. Bushing
,Answer: A. Elbow
Rationale: Elbows are designed to change the direction of piping. In
drainage systems, fittings must be selected and installed so that they
provide proper flow and minimize the potential for obstruction.
4. What is the main purpose of a cleanout in a drainage system?
A. Increase water temperature
B. Provide access for cleaning and servicing the drainage piping
C. Reduce water pressure
D. Prevent fixture siphonage
Answer: B. Provide access for cleaning and servicing the drainage
piping
Rationale: Cleanouts provide access to drainage piping so blockages
can be removed and the piping can be inspected or maintained. Their
location and accessibility are important for effective system
maintenance.
5. What is the primary function of a venting system in a plumbing
drainage system?
, A. Supply drinking water
B. Maintain proper drainage-system air pressure and protect trap seals
C. Increase water heater capacity
D. Filter wastewater
Answer: B. Maintain proper drainage-system air pressure and protect
trap seals
Rationale: Proper venting allows air to enter and leave the drainage
system, helping maintain balanced pressures. This reduces the
possibility of trap seal loss caused by siphonage or pressure
fluctuations.
6. A fixture trap that loses its water seal because wastewater flowing
through a drain creates negative pressure is experiencing:
A. Backpressure
B. Siphonage
C. Thermal expansion
D. Water hammer
Answer: B. Siphonage
