MINNEAPOLIS JOURNEYMAN PLUMBER WITH GAS –
498-MN-MI CONTRACTOR EXAM PRACTICE
QUESTIONS AND ANSWERS - LATEST AND COMPLETE
UPDATE WITH VERIFIED SOLUTIONS – ASSURED PASS
WITH INSTANT DOWNLOAD PDF.
1. Which type of pipe is most suitable for underground potable water supply in
Minneapolis, considering frost protection and municipal codes?
A. PVC Schedule 40
B. PEX
C. Galvanized steel
D. CPVC
Rationale: PEX is flexible, resistant to freeze damage, and meets
Minneapolis plumbing code requirements for underground potable water
applications.
2. A gas water heater is installed in a residential home. Which component
prevents backflow of water into the gas line?
A. Gas shutoff valve
B. Pressure relief valve
C. Backflow preventer
D. T&P valve
Rationale: A backflow preventer ensures that water cannot flow back into
the gas line, protecting the system from contamination and complying with
Minnesota plumbing code.
3. You notice excessive water hammer in a newly installed PEX system.
Which solution is most appropriate?
A. Increase pipe diameter
B. Install water hammer arrestors near fixtures
, C. Reduce water pressure
D. Replace PEX with copper
Rationale: Water hammer arrestors absorb sudden pressure spikes,
preventing damage and noise. PEX flexibility alone does not eliminate
hammering.
4. According to Minnesota plumbing code, the maximum distance a horizontal
fixture drain can extend before requiring a cleanout is:
A. 20 feet
B. 50 feet
C. 75 feet
D. 100 feet
Rationale: Minnesota code specifies cleanouts at intervals not exceeding 50
feet on horizontal drains for accessibility and maintenance.
5. When sizing a gas pipe for a 150,000 BTU/hr boiler using natural gas, which
factor must be considered?
A. Pipe color
B. Pipe length and fittings
C. Gas type, length, and appliance input
D. Ambient temperature
Rationale: Proper gas pipe sizing depends on the total appliance input, the
length of the pipe run, the number of fittings, and the type of gas used.
6. Which of the following is a requirement for venting a residential plumbing
system in Minneapolis?
A. Each fixture must have a separate vent
B. The vent must extend at least 6 inches above the roof penetration
C. Vents may terminate under eaves
D. No vent is required for floor drains
, Rationale: Minnesota plumbing code requires vents to extend above the roof
surface to prevent sewer gases from entering the building.
7. A plumber notices corrosion on a galvanized steel water supply line. Which
is the best corrective action?
A. Apply anti-corrosion paint
B. Replace with copper or PEX piping
C. Wrap in electrical tape
D. Flush with chlorinated water
Rationale: Corrosion reduces pipe integrity. Replacing the line with
approved materials like copper or PEX ensures long-term reliability and
code compliance.
8. Which fixture requires a trap primer according to Minneapolis plumbing
standards?
A. Kitchen sink
B. Bathtub
C. Floor drain in a utility room
D. Washing machine
Rationale: Floor drains that are infrequently used require trap primers to
maintain a water seal and prevent sewer gas from entering occupied spaces.
9. During a gas system inspection, you notice the regulator is set above the
appliance rating. The correct action is:
A. Document and leave as-is
B. Adjust the regulator to match appliance specifications
C. Replace the appliance
D. Install an additional vent
Rationale: Regulators must deliver gas at the correct pressure for safe
appliance operation. Overpressure can cause malfunction or fire hazards.
, 10.For a residential water heater, what is the purpose of the T&P (temperature
and pressure) relief valve?
A. Increase water temperature
B. Prevent tank overpressure or overheating
C. Control water flow
D. Improve energy efficiency
Rationale: T&P valves are safety devices designed to relieve excessive
pressure or temperature, preventing tank rupture or explosions.
11.A customer requests a backflow assembly test. Which is the licensed
professional required to perform this in Minnesota?
A. Any plumber
B. HVAC technician
C. Certified backflow tester
D. General contractor
Rationale: Minnesota requires a certified backflow tester to ensure proper
installation, testing, and compliance with state regulations.
12.You are installing a gas water heater in a confined space. Which ventilation
requirement must be observed?
A. No vent is required
B. Adequate combustion air must be provided according to appliance
rating
C. Venting is optional if natural gas is used
D. Vent may terminate at floor level
Rationale: Confined spaces require adequate combustion air to prevent
incomplete combustion and accumulation of carbon monoxide.
13.Which type of fitting is preferred when joining PEX to a copper pipe in a
residential water system?
498-MN-MI CONTRACTOR EXAM PRACTICE
QUESTIONS AND ANSWERS - LATEST AND COMPLETE
UPDATE WITH VERIFIED SOLUTIONS – ASSURED PASS
WITH INSTANT DOWNLOAD PDF.
1. Which type of pipe is most suitable for underground potable water supply in
Minneapolis, considering frost protection and municipal codes?
A. PVC Schedule 40
B. PEX
C. Galvanized steel
D. CPVC
Rationale: PEX is flexible, resistant to freeze damage, and meets
Minneapolis plumbing code requirements for underground potable water
applications.
2. A gas water heater is installed in a residential home. Which component
prevents backflow of water into the gas line?
A. Gas shutoff valve
B. Pressure relief valve
C. Backflow preventer
D. T&P valve
Rationale: A backflow preventer ensures that water cannot flow back into
the gas line, protecting the system from contamination and complying with
Minnesota plumbing code.
3. You notice excessive water hammer in a newly installed PEX system.
Which solution is most appropriate?
A. Increase pipe diameter
B. Install water hammer arrestors near fixtures
, C. Reduce water pressure
D. Replace PEX with copper
Rationale: Water hammer arrestors absorb sudden pressure spikes,
preventing damage and noise. PEX flexibility alone does not eliminate
hammering.
4. According to Minnesota plumbing code, the maximum distance a horizontal
fixture drain can extend before requiring a cleanout is:
A. 20 feet
B. 50 feet
C. 75 feet
D. 100 feet
Rationale: Minnesota code specifies cleanouts at intervals not exceeding 50
feet on horizontal drains for accessibility and maintenance.
5. When sizing a gas pipe for a 150,000 BTU/hr boiler using natural gas, which
factor must be considered?
A. Pipe color
B. Pipe length and fittings
C. Gas type, length, and appliance input
D. Ambient temperature
Rationale: Proper gas pipe sizing depends on the total appliance input, the
length of the pipe run, the number of fittings, and the type of gas used.
6. Which of the following is a requirement for venting a residential plumbing
system in Minneapolis?
A. Each fixture must have a separate vent
B. The vent must extend at least 6 inches above the roof penetration
C. Vents may terminate under eaves
D. No vent is required for floor drains
, Rationale: Minnesota plumbing code requires vents to extend above the roof
surface to prevent sewer gases from entering the building.
7. A plumber notices corrosion on a galvanized steel water supply line. Which
is the best corrective action?
A. Apply anti-corrosion paint
B. Replace with copper or PEX piping
C. Wrap in electrical tape
D. Flush with chlorinated water
Rationale: Corrosion reduces pipe integrity. Replacing the line with
approved materials like copper or PEX ensures long-term reliability and
code compliance.
8. Which fixture requires a trap primer according to Minneapolis plumbing
standards?
A. Kitchen sink
B. Bathtub
C. Floor drain in a utility room
D. Washing machine
Rationale: Floor drains that are infrequently used require trap primers to
maintain a water seal and prevent sewer gas from entering occupied spaces.
9. During a gas system inspection, you notice the regulator is set above the
appliance rating. The correct action is:
A. Document and leave as-is
B. Adjust the regulator to match appliance specifications
C. Replace the appliance
D. Install an additional vent
Rationale: Regulators must deliver gas at the correct pressure for safe
appliance operation. Overpressure can cause malfunction or fire hazards.
, 10.For a residential water heater, what is the purpose of the T&P (temperature
and pressure) relief valve?
A. Increase water temperature
B. Prevent tank overpressure or overheating
C. Control water flow
D. Improve energy efficiency
Rationale: T&P valves are safety devices designed to relieve excessive
pressure or temperature, preventing tank rupture or explosions.
11.A customer requests a backflow assembly test. Which is the licensed
professional required to perform this in Minnesota?
A. Any plumber
B. HVAC technician
C. Certified backflow tester
D. General contractor
Rationale: Minnesota requires a certified backflow tester to ensure proper
installation, testing, and compliance with state regulations.
12.You are installing a gas water heater in a confined space. Which ventilation
requirement must be observed?
A. No vent is required
B. Adequate combustion air must be provided according to appliance
rating
C. Venting is optional if natural gas is used
D. Vent may terminate at floor level
Rationale: Confined spaces require adequate combustion air to prevent
incomplete combustion and accumulation of carbon monoxide.
13.Which type of fitting is preferred when joining PEX to a copper pipe in a
residential water system?
