Master Plumber Exam Water Heaters and Hot Water Systems

Question 1

What is the maximum recommended water heater temperature setting to prevent scalding at residential fixtures?

Accepted Answer

120°F

Answer

110°F

Answer

130°F

Answer

140°F

Question 2

What is the primary purpose of a Temperature and Pressure Relief (T&P) valve on a water heater?

Accepted Answer

To release water if temperature or pressure becomes dangerously high

Answer

To regulate incoming water flow

Answer

To control water hardness and mineral buildup

Answer

To measure the heater's energy efficiency

Question 3

Using the standard heat formula, approximately how many BTUs are needed to raise 40 gallons of water from 50°F to 120°F?

Accepted Answer

23,300 BTU

Answer

14,000 BTU

Answer

18,500 BTU

Answer

35,000 BTU

Question 4

What is the first-hour rating (FHR) of a storage water heater?

Accepted Answer

The gallons of hot water the heater can supply in one hour starting with a full tank

Answer

The time in minutes to fully recover a depleted tank

Answer

The recovery rate in BTU per hour at a 90°F temperature rise

Answer

The maximum flow rate in GPM at the closest fixture

Question 5

What type of water heater extracts heat from surrounding air using a refrigerant cycle to heat the stored water?

Accepted Answer

Heat pump water heater

Answer

Condensing water heater

Answer

Indirect water heater

Answer

Tankless water heater

Question 6

What is the purpose of a dip tube inside a storage-type water heater?

Accepted Answer

To direct cold incoming water to the bottom of the tank

Answer

To drain sediment from the tank bottom during flushing

Answer

To allow air to escape when the tank is filling

Answer

To circulate water evenly around the heating element

Question 7

When installing a gas water heater, what is the minimum required clearance between the draft hood diverter and any combustible material?

Accepted Answer

6 inches

Answer

1 inch

Answer

2 inches

Answer

12 inches