Monday, February 27, 2017

4th Class Power Engineering Part B Ch103- Ch108 Questions & Answers.

CH.103
Automatic snow melting systems can use:
A )  hot water and antifreeze mixed
B )  electric resistance heating
C )  infrared lamps mounted above sidewalks and ramps
D )  hot water and ethylene glycol mixed
E )  all of the above

In a one pipe hot water system the fitting that directs the water to each converter is called the:
A )  diverter
B )  trap
C )  vent valve
D )  separator
E )  lead

In a hot water system compared to a steam heating system, if there is a leak damage will:
A )  be greater in the steam system
B )  be greater in the hot water system
C )  be about the same in either system
D )  depend on where the boiler is located in the system
E )  be minimal due to the automatic drain system

 A hot water boiler of the same output is:
A )  larger than a steam boiler
B )  smaller than a steam boiler
C )  the same size as a steam boiler
D )  taller than a steam boiler
E )  shorter than a steam boiler

The maximum temperature of water in a gravity hot water system is:
A )  65 °C
B )  70 °C
C )  77 °C
D )  87 °C
E )  67 °C

In radiant heating system changes are:
A )  difficult to make
B )  easy to make
C )  as easy to make as in any other heating system
D )  dependent on availability of materials
E )  dependent on location

Snow melting systems are usually filled with:
A )  water only
B )  methanol and water
C )  ethylene glycol and water
D )  steam
E )  warm air

Which of the following use a boiler in the system?1. steam heating 2. electric heating 3. steam to hot water system4. hot water heating
A )  1, 2
B )  2, 3
C )  1, 4
D )  3, 4
E )  1, 3, 4

A hot water system which circulates water through the pipes with a pump is known as a:
A )  circulating system
B )  forced system
C )  pumped system
D )  gravity system
E )  return system

A forced hot water circulating system can be classified as the following type:
A )  loop system
B )  one pipe system
C )  two pipe direct return system
D )  two pipe reverse return system

E )  all of the above 

CH.104
The purpose of an expansion tank is to:
A )  store heat while the boiler is firing
B )  allow for the expansion of water in the system
C )  prevent the system from overflowing
D )  to prevent the water in the system from freezing
E )  to prevent water lock in the system

The purpose of a pressure reducing valve is to:
A )  level out the flow of steam or hot water
B )  automatically reduce pressure and maintain it
C )  reduce water hammer in a heating system
D )  maintain hot water at a required pressure
E )  to reduce the feedwater pressure to the boiler

An air separator should always be installed in:
A )  a horizontal pipe
B )  a cross tee
C )  a vertical pipe
D )  an expansion tank
E )  a converter

Improper location of the circulating pump and expansion tank can cause:
A )  the circulating pump to cavitate
B )  some points in the system to be under negative pressure
C )  air to be drawn into the system
D )  vapour bubbles to form in the circulating pump
E )  all of the above

To regulate the flow of water to a zone circuit a:
A )  flow control valve is used
B )  diverter fitting is used
C )  gate valve is used
D )  pressure reducing valve is used
E )  balancing valve is used
The temperature control on a steam to hot water converter, controls:
A )  the pump speed
B )  the steam temperature
C )  the water flow
D )  the steam control valve
E )  the firing rate

Excessive pressure build-up due to a rise in temperature and the resulting expansion of the water in the system is prevented by the use of:
A )  a float tank
B )  a relief valve
C )  an expansion tank
D )  a cushion valve
E )  a safety valve

Valves in heating systems should be _______________ if they do not shut off tightly.
A )  discarded
B )  heated
C )  bypassed
D )  repaired
E )  reported
Air is removed from a hot water system by which of the following:1. air vents2. deaerators3. air condensers4. air separators
A )  1, 2
B )  2, 3
C )  1, 4
D )  2, 4
E )  1, 3

Diverter fittings are used in the supply lines to heating units:
A )  to compensate for a low heating load
B )  when a higher heating output is required from the heating unit
C )  when the distance from the boiler to heating unit is short
D )  when there are no balancing valves installed in the supply line
E )  when a hydraulic balance must be corrected 

CH.105
The advantage of having duct furnaces instead of a large central furnace is:
A )  less initial cost
B )  easier installation
C )  better control of heat in each zone of the building
D )  that they require less space
E )  lower maintenance costs

Lowboy furnaces are just over:
A )  1.0 m in height
B )  0.8 m in height
C )  1.4 m in height
D )  1.6 m in height
E )  1.2 m in height

In a fin-coil heat exchanger the primary source of heat for the exchanger is:
A )  steam or hot water
B )  gas
C )  oil
D )  solar
E )  radiant

In a warm air heating system the cold air return registers are located:
A )  in exterior walls
B )  in interior locations
C )  under windows
D )  in floors
E )  in ceilings

The power supply for an electric resistance coil furnace is:
A )  60 V
B )  120 V
C )  240 V
D )  220 V
E )  480 V

High efficiency furnaces and heaters range in annual fuel utilisation efficiency (AFUE) from:
A )  94 - 98%
B )  80 - 95%
C )  70 - 75%
D )  60 - 70%
E )  50 - 60%

The major disadvantage of an electric resistance coil furnace for warm air heating is:
A )  the high cost of electricity
B )  the danger from electric shock
C )  the high cost of maintenance
D )  the large size of the furnace
E )  the location of electrical wiring

In a pulse combination furnace the stated efficiency is:
A )  94 - 98%
B )  80 - 95%
C )  70 - 75%
D )  60 - 70%
E )  50 - 60% 

In high efficiency furnaces if the temperature of the flue gas drops below 65 degrees C the:
A )  flue gas will condense
B )  water vapour will condense
C )  furnace burner will shut down
D )  furnace burner will start up
E )  furnace vent will close

A type of directly fired space heater is:
A )  a unit heater
B )  a floor furnace
C )  a wall furnace
D )  all of the above
E )  none of the above 

CH.106
Electronic filters will remove:
A )  all particles from the air
B )  fine particles from the air
C )  odour producing gases from the air
D )  smoke from the air
E )  all of the above

Furnace heat exchangers should be checked for corrosion because:
A )  carbon monoxide could leak into the building
B )  the holes reduce the furnace efficiency
C )  cold air could leak into the building
D )  too much air would enter the furnace
E )  the air will become too dry for comfortable heating

Plugged __________ on warm air heating and ventilating systems, limit the air flow and result in insufficient heating and a waste of fuel.
A )  filters
B )  drain lines
C )  diverters
D )  univents
E )  convectors

Heat exchangers in gas fired furnaces are made of:
A )  brass
B )  copper
C )  aluminium
D )  steel
E )  cast iron

Which of the following is a type of outlet in a warm air heating system?
A )  a grill
B )  a register
C )  a ceiling diffuser
D )  a perforated panel
E )  all of the above

In a warm air heating system, the heated air should enter the rooms preferably via the:
A )  high wall registers on the inside wall
B )  baseboard registers on the inside wall
C )  baseboard registers on the outside wall
D )  high wall registers on the outside wall
E )  unit heaters on the outside wall

Supply outlets should always be located:
A )  in walls
B )  in floors
C )  in ceilings
D )  to best prevent cold drafts
E )  in baseboards

Air filters can be divided into two groups:
A )  mechanical and rotating drum
B )  electronic and steam
C )  dry and wet
D )  steam and rotating drum
E )  mechanical and electronic

The perimeter loop system of furnace ducting is ideal for a building with:
A )  no insulation in the walls
B )  concrete walls
C )  no basement
D )  low head room in the basement
E )  no cold air returns

Electronic filters will remove:
A )  all particles from the air
B )  fine particles from the air
C )  odour producing gases from the air
D )  smoke from the air
E )  all of the above 

CH.107
Natural ventilation is improved by the use of a roof:
A )  ventilator
B )  radiator
C )  grille
D )  louver
E )  panel

Mechanical ventilation can be divided into which types?
A )  natural air intake, natural exhaust
B )  mechanical air intake, natural exhaust
C )  natural air intake, mechanical exhaust
D )  natural intake, natural exhaust
E )  none of the above

Living organisms that must be removed from the air are:
A )  insects and pollen
B )  bacteria and insects
C )  bacteria and spores
D )  pollen and spores
E )  pollen and bacteria

In a mechanical air intake, natural exhaust ventilation system the pressure in the building is:
A )  well below atmospheric pressure
B )  slightly below atmospheric pressure
C )  at atmospheric pressure
D )  slightly above atmospheric pressure
E )  well above atmospheric pressure

Actual ventilation rates may vary per person from:
A )  0.5 to 0.6 m3/min
B )  0.5 to 0.75 m3/min
C )  0.2 to 1.2 m3/min
D )  0.14 to 1.5 m3/min
E )  1.0 to 1.5 m3/min

Ventilation can be divided into two basic methods:
A )  forced and natural
B )  mechanical and natural
C )  forced and mechanical
D )  natural and warmed air
E )  natural and cold air 

CH.108
Infrared radiant energy is directed towards:
A )  ceilings
B )  walls
C )  windows
D )  floors
E )  doors

In an internally fired, gas fired infrared heater, the surface temperature is about:
A )  300 °C
B )  400 °C
C )  500 °C
D )  600 °C
E )  700 °C

The quartz lamp heating element will respond:
A )  instantaneously
B )  in a few seconds
C )  in about one minute
D )  in about thirty seconds
E )  in about three minutes

Gas-fired infrared heaters use the principle of:
A )  heating a gas
B )  heating a solid surface
C )  heating a liquid
D )  heating a porous material
E )  all of the above

Infrared heaters are usually mounted:
A )  overhead
B )  on walls
C )  in floors
D )  under windows
E )  over doors

A low temperature catalytic heater contains a layer of:
A )  metal impregnated with a catalyst
B )  wool fibre impregnated with a catalyst
C )  plastic fibre impregnated with a catalyst
D )  glass wool impregnated with a catalyst
E )  porous glass impregnated with a catalyst 

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