Journeyman Plumbers Exam Water Heaters and Hot Water Systems

Question 1

Where must a temperature and pressure (T&P) relief valve discharge pipe terminate?

Accepted Answer

Within 6 inches of the floor

Answer

T&P relief valve discharge pipes must terminate within 6 inches of the floor to direct scalding water safely downward away from occupants.

Question 2

What is the purpose of the dip tube in a storage tank water heater?

Accepted Answer

To direct incoming cold water to the bottom of the tank

Answer

The dip tube directs incoming cold water to the bottom of the tank so it does not mix with the hot water at the top, ensuring efficient delivery of hot water.

Question 3

What is the primary purpose of the sacrificial anode rod in a tank-type water heater?

Accepted Answer

To protect the steel tank lining from corrosion through galvanic action

Answer

The anode rod (typically magnesium or aluminum) corrodes sacrificially through electrochemical action, protecting the steel tank from rust and premature failure.

Question 4

What is the maximum water heater thermostat setting recommended by most US plumbing codes to prevent scalding in residential occupancies?

Accepted Answer

120°F (49°C)

Answer

Most US plumbing codes recommend setting residential water heater thermostats no higher than 120°F to prevent scalding injuries, especially for children and elderly occupants.

Question 5

At what minimum height above the garage floor must the ignition source of a gas water heater be located?

Accepted Answer

18 inches

Answer

Gas water heater ignition sources must be at least 18 inches above the garage floor to prevent ignition of gasoline vapors, which are heavier than air and pool near the floor.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Water Heaters and Hot Water Systems