Deck 33: Hydronic Heat

Question 1

The pressure relief valve ____.

A) regulates the pressure of the water in the supply line
B) is set to relieve the pressure in the boiler below its maximum design pressure
C) shuts the boiler off if the water temperature gets too high
D) relieves the pressure in the expansion tank

Answer 1

B

Question 2

Expansion tanks must always be bled from the top until all of the air is removed from it.

Answer 2

False

Question 3

A tankless domestic water system provides hot water from a coil in the boiler.

Answer 3

True

Question 4

A pressure relief valve is set at 30 psig. The valve is constantly opening and flooding the floor. What is causing the relief valve to constantly open?

A) The water-regulating valve is broken.
B) The system is overfiring.
C) The system needs to be calibrated.
D) The system requires a new boiler.

Question 5

Air in a hydronic system can cause ____.

A) reduced water circulation
B) increased water concentration
C) corrosion
D) Both a and c.

Question 6

Automatic air vents rely on an internal disc that swells when water is sensed.

Question 7

A series loop hydronic system is not desirable for use in a large residence because ____.

A) all of the heated water will flow to all rooms
B) some rooms will overheat before other rooms are warm
C) it is difficult to install and maintain
D) Both a and b.

Question 8

In a series loop, the water going through the last terminal unit will be the same temperature as the water through the first terminal unit.

Question 9

The more common type of expansion tank is the ____ expansion tank.

A) compression
B) standard
C) restricted
D) diaphragm-type

Question 10

A column of water 1 ft high exerts a pressure of ____.

A) 0.277 psig
B) 0.299 psig
C) 0.433 psig
D) 14.696 psig

Question 11

A high-limit control on a hot water boiler is needed to ____.

A) regulate the amount of water to each section of baseboard
B) regulate the water in the supply line to the boiler
C) balance the water flow rate in the piping system
D) protect the boiler against excessive water temperatures

Question 12

The series loop system is the hydronic system that is found most often, primarily because of the  ____.

A) heated water flows in the same direction in parallel pipes
B) first terminal units being supplied will be warmer than the later ones
C) possibility of having individual temperature control for each area being heated
D) low installation costs

Question 13

An expansion joint is a device used to ____.

A) prevent damage between boiler sections
B) enlarge the expansion tank in the system
C) allow for expansion and contraction of the loop piping with water temperature changes
D) connect the manual vent into the system

Question 14

The more sections a boiler has, the higher its capacity will be.

Question 15

The only place a bleed valve is needed is on top of the boiler.

Question 16

It is important to note that the air separator does not remove air from the system .

Question 17

The reason for using zone valves on a hydronic heating system is to ____.

A) allow different areas of the structure to maintain different temperatures
B) reduce the chance of a water leak
C) prevent unused parts of the house from getting warm, and wasting energy
D) Both a and c.

Question 18

Hydronic heating systems are systems in which water or ____________________ carries the heat through pipes to the areas to be heated .

Question 19

Hydronic heat circulators are centrifugal pumps.

Question 20

The expansion tank provides a means of removing the air from the system as well as provides ____ .

A) a space for excess water from the supply source
B) water for the domestic hot water coil
C) a space for the water expansion and contraction with water temperature changes
D) All of the above.

Question 21

Zone control valves are controlled by ____________________.

Question 22

Discuss the outdoor reset control.

Question 23

Explain how a centrifugal circulating pump creates flow in the hydronic system .

Question 24

The low-water ____________________ valve is responsible for deenergizing the hydronic system in the event the level of water in the system drops below the desired point .

Question 25

An automatic air vent controls the airflow out of the system by means of a(n) ____________________, which rises and falls with the amount of air in the system.

Question 26

Most residences with modern hydronic heating systems use ____________________ baseboard heat transfer for terminal heating units.

Question 27

In hot water hydronic systems, water is heated and circulated through pipes to a heat transfer component called a(n) ____________________ unit .

Question 28

Explain the purpose of the pressure relief valve.

Question 29

What would happen if a hydronic system was installed without an expansion tank?

Question 30

The high-limit control, like the ____________________, is a device that opens and closes its contacts in response to boiler water temperature .

Question 31

Pumps generally have a cast-iron body with the impeller and other moving parts made of ____________________ or nonferrous metals .

Question 32

The vanes of the impellers used in circulating pumps in hot water heating systems are usually enclosed, and are referred to as ____________________ impellers .

Question 33

On systems that use two-port zone valves, excessive pressure in the supply header may result when multiple zone valves ____________________.

Question 34

Why must the expansion tank always be located higher than the boiler?

Question 35

What is the purpose of a system pressure differential bypass valve?