Unit 22 - Chapter 100 Flashcards

0
Q

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

A

The high cost of electricity

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1
Q

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

A

In interior locations

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2
Q

Lowboy furnaces are just

A

1.2 m in height

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3
Q

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

A

Better control of heat in each zone of the building

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4
Q

The power supply for an electric resistance cool furnace is

A

240 V

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5
Q

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

A

Steam or hot water

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6
Q

A type of directly fired space heater is

A
  • a unit heater
  • a floor furnace
  • a wall furnace
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7
Q

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

A

80 - 95%

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8
Q

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

A

Water vapour will condense

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9
Q

In a pulse combination furnace the stated efficiency is

A

94 - 98%

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10
Q

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

A

Glycol heater

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11
Q

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

A

Blower noise can be carried through the ducts

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12
Q

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

A

60, 70

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13
Q

The lowboy furnace is used where

A

Headroom is limited

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14
Q

Horizontal furnaces are only about

A

0.6 m high and used where there is limited headroom

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15
Q

Horizontal furnaces are installed

A

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

16
Q

Downflow furnaces are used in

A

Buildings without basements

17
Q

Heating systems with duct furnaces have the advantage that

A

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

18
Q

Electric resistance furnaces are much more compact because

A

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

19
Q

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

A

A high temperature limit control

20
Q

Increases in furnace efficiency can be achieve by

A

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

21
Q

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

A

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

22
Q

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

A

Installation and maintenance costs are lower

23
Q

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

A

High temperature of flue gases

24
In high efficiency furnaces, if the temperature of the flue gas drops below 65'C, the
Water vapour will condense
25
In a fin coil heat exchanger, the heat exchanger is
A steam or hot water coil
26
In high efficiency furnace or heaters the temperature of the flue gases are ___ in the secondary heat exchangers
Below the dew point
27
One of the advantages of forced warm air heating systems is
That controlled amounts of ventilation air can be admitted
28
Electronic ignition raises efficiency to
78%
29
One of the disadvantages of forced warm air heating systems is the
Systems can be noisy