Journeyman Plumbers Exam Water Heaters and Hot Water Systems 3

Question 1

A water heater is rated for a maximum working pressure of 150 PSI. What is the maximum pressure rating allowed for the T&P relief valve installed on this heater?

Accepted Answer

150 PSI

Answer

100 PSI

Answer

125 PSI

Answer

175 PSI

Question 2

Which pipe material is NOT permitted for use as a T&P relief valve discharge pipe?

Accepted Answer

Schedule 40 PVC pipe

Answer

Copper tubing

Answer

CPVC pipe

Answer

Galvanized steel pipe

Question 3

What is the primary energy advantage of a tankless (on-demand) water heater compared to a conventional storage water heater?

Accepted Answer

Elimination of standby heat loss

Answer

Lower upfront equipment and installation cost

Answer

Higher flow rates for simultaneous fixture use

Answer

Longer equipment service life

Question 4

What is the purpose of a thermostatic mixing valve (tempering valve) installed at the outlet of a water heater?

Accepted Answer

To blend hot and cold water to deliver a safe, preset mixed temperature

Answer

To increase water pressure delivered to fixtures

Answer

To prevent thermal expansion from building pressure

Answer

To control gas flow to the burner assembly

Question 5

What is the minimum horizontal clearance required between a power vent water heater exhaust termination cap and a window or door opening?

Accepted Answer

4 feet

Answer

6 inches

Answer

12 inches

Answer

10 feet

Question 6

When may a plumber reduce the diameter of a T&P relief valve discharge pipe below the size of the valve outlet?

Accepted Answer

Never — reducing the pipe size below the valve outlet is prohibited

Answer

When the total pipe length is under 10 feet

Answer

When the pipe is routed vertically downward

Answer

When an approved check valve is installed on the pipe

Question 7

What is required when a water heater is installed in an area subject to flooding or where the unit could be submerged?

Accepted Answer

The heater must be elevated above the base flood elevation

Answer

The heater must be waterproofed with approved sealant

Answer

A backflow preventer must be installed on the cold supply

Answer

Gas water heaters are prohibited; only electric units may be used