Unit 22 - Chapter 100

Question 0

A major disadvantage of an electric resistance cool furnace for warm air heating is

Answer 0

The high cost of electricity

Question 1

In a warm air heating system the cold air return registers are located

Answer 1

In interior locations

Question 2

Lowboy furnaces are just

Answer 2

1.2 m in height

Question 3

The advantage of having duct furnaces instead of a large central furnace is

Answer 3

Better control of heat in each zone of the building

Question 4

The power supply for an electric resistance cool furnace is

Answer 4

240 V

Question 5

In a fin coil heat exchanger the primary source for the exchanger is

Answer 5

Steam or hot water

Question 6

A type of directly fired space heater is

Answer 6

• a unit heater
• a floor furnace
• a wall furnace

Question 7

High efficiency furnaces and heaters range in annual fuel utilization efficiency from

Answer 7

80 - 95%

Question 8

In high efficiency furnaces if the temperature of the flue gas drops below 65’C the

Answer 8

Water vapour will condense

Question 9

In a pulse combination furnace the stated efficiency is

Answer 9

94 - 98%

Question 10

Which is not a type of heat exchanger used in forced warm air heating systems?

Answer 10

Glycol heater

Question 11

What is not an advantage of a forced air heating system?

Answer 11

Blower noise can be carried through the ducts

Question 12

In a pulse burner, the pulse combustion process occurs about ___ to ___ times per second

Answer 12

60, 70

Question 13

The lowboy furnace is used where

Answer 13

Headroom is limited

Question 14

Horizontal furnaces are only about

Answer 14

0.6 m high and used where there is limited headroom

Question 15

Horizontal furnaces are installed

Answer 15

Where headroom is limited such as in attics or crawl spaces or suspended from the ceiling

Question 16

Downflow furnaces are used in

Answer 16

Buildings without basements

Question 17

Heating systems with duct furnaces have the advantage that

Answer 17

They can easily match the varying heat demand of the different zones of a building

Question 18

Electric resistance furnaces are much more compact because

Answer 18

The large heat exchange section as well as the combustion equipment has been eliminated

Question 19

Elements in electric resistance coils are protected from overheating due to airflow by

Answer 19

A high temperature limit control

Question 20

Increases in furnace efficiency can be achieve by

Answer 20

Installing a vent damper, electronic ignition, and improved heat exchanger design

Question 21

A fired heater which is installed on location where eat is needed and heats the air directly without the use of any ducting is

Answer 21

A unit heater (as well as a floor and wall furnace)

Question 22

Forced warm air heating systems are used more extensively to hear residences since

Answer 22

Installation and maintenance costs are lower

Question 23

One of the biggest heat losses in warm air furnaces and space heaters is

Answer 23

High temperature of flue gases

Question 24

In high efficiency furnaces, if the temperature of the flue gas drops below 65’C, the

Answer 24

Water vapour will condense

Question 25

In a fin coil heat exchanger, the heat exchanger is

Answer 25

A steam or hot water coil

Question 26

In high efficiency furnace or heaters the temperature of the flue gases are ___ in the secondary heat exchangers

Answer 26

Below the dew point

Question 27

One of the advantages of forced warm air heating systems is

Answer 27

That controlled amounts of ventilation air can be admitted

Question 28

Electronic ignition raises efficiency to

Answer 28

78%

Question 29

One of the disadvantages of forced warm air heating systems is the

Answer 29

Systems can be noisy