3e151 B Set Vol 2

100 Questions | By Enorab | Updated: Mar 21, 2022 | Attempts: 783

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UREs for B set of 3E151 cdcs Vol 2.

Questions and Answers

1.

The inside part of the a heat exchanger in a forced-warm air furnace is known as the
- A.
  
  Burner cone
- B.
  
  Draft chamber
- C.
  
  Casing chamber
- D.
  
  Combustion chamber
2.

Three common types of bearing used on warm-air furnace assemblies
- A.
  
  Anti-friction, sleeve, and bronze
- B.
  
  Sleeve, thrust, and anti-friction
- C.
  
  Plain, thrust, and anti-friction
- D.
  
  Thrust, plain, and bronze
3.

What type of warm-air furnace is known as a high-boy furnace?
- A.
  
  Horizontal
- B.
  
  Downflow
- C.
  
  Gravity
- D.
  
  Upflow
4.

Gas burners primary controls operate in response to signals received from
- A.
  
  Relays
- B.
  
  Switches
- C.
  
  Thermostats
- D.
  
  A heating element
5.

When the tempetature in a gas-fired furnance becomes excessive, what unit stops the burner?
- A.
  
  Delayed-action control
- B.
  
  Starting control
- C.
  
  Ignition control
- D.
  
  Limit control
6.

The delayed-action control is a primary control that is usually used with
- A.
  
  A stoker
- B.
  
  An oil burner
- C.
  
  A gas burner
- D.
  
  A coal hand-fired furnace
7.

The most important inspection you perform on a gas-fired furnace is one for
- A.
  
  Power
- B.
  
  Unit size
- C.
  
  A gas leak
- D.
  
  Unit location
8.

What is the most serious defect to look for when you inspet a heat exchanger?
- A.
  
  Warped metal
- B.
  
  Soot deposits
- C.
  
  Blockages
- D.
  
  Cracks
9.

When you perform a test to ensure that the safety limit control is operating properly, which circuit do you disconnect?
- A.
  
  Blower
- B.
  
  Burner
- C.
  
  Pilot
- D.
  
  Main
10.

What type of gas space heaters can be gravity or mechanical air-circulation type and vented or unvented type?
- A.
  
  Ceiling
- B.
  
  Floor
- C.
  
  Room
- D.
  
  Wall
11.

Which space heater must be used inly in a well-ventilated rooms?
- A.
  
  Wall
- B.
  
  Room
- C.
  
  Vented
- D.
  
  Unvented
12.

What is the maximum Btu input for an unvented space heater?
- A.
  
  50,000 btu/h
- B.
  
  40,000 btu/h
- C.
  
  30,000 btu/h
- D.
  
  20,000 btu/h
13.

Which type of space heater control valve has an infinite number of fuel firing rates between high fire and low fire?
- A.
  
  Step-modulating
- B.
  
  Single-stage
- C.
  
  Two-stage
- D.
  
  Manual
14.

Whose instructions must you follow when you inspect gas-fired heaters?
- A.
  
  Air force bulletins
- B.
  
  Air force procedures
- C.
  
  Manufacturers' instructions
- D.
  
  Local procedures and air force bulletins
15.

What method of heat transfer is used when floors or other objects reradiate to the air?
- A.
  
  Conduction
- B.
  
  Convection
- C.
  
  Radiation
- D.
  
  Absorption
16.

Infrared heaters are not used in an area that contains ignitable dust, gases, or vapors in hazardous concentrations because of
- A.
  
  Their very low surface temperature
- B.
  
  Their high surface temperature
- C.
  
  The porosity of their ceramic elements
- D.
  
  The possibility of corrosion damage to the elements
17.

The fan control has two settings; the fan OFF temperature is generally set at
- A.
  
  20 to 25*F above the desired room temperature
- B.
  
  15 to 20*F above the desired room temperature
- C.
  
  10 to 15*F above the desired room temperature
- D.
  
  5 to 10*F above the desired room temperature
18.

While troubleshooting a warm-air heating system, you notice the flame burning in a long, yellow-tipped manner? What would cause this to happen?
- A.
  
  A strong updraft
- B.
  
  A very weak cross draft
- C.
  
  Low voltage in the control circuit
- D.
  
  Insufficient primary combustion
19.

When troubleshooting a gas-fired warm-air furnace, the unit is functioning eletrically but does not operate. What could be the cause of the type malfunction?
- A.
  
  An open gas valve
- B.
  
  A closed gas valve
- C.
  
  An open alarm circuit
- D.
  
  A closed thermostat circuit
20.

What surrounds the tubes of water-tube boiler?
- A.
  
  Hot gases
- B.
  
  Hot air
- C.
  
  Water
- D.
  
  Steam
21.

An increase in pressure and the surface of water will
- A.
  
  Increase the boiling point
- B.
  
  Decrease the boiling point
- C.
  
  Increase the molecular count
- D.
  
  Decrease the molecular count
22.

The formula for determining the temperature of water at a given steam pressure is
- A.
  
  Square root of the psi + 14 x 198
- B.
  
  Square root of the psi x 14 + 198
- C.
  
  198 X 14 + square root of the psi
- D.
  
  198 + 14 x the square root of the psi
23.

The internal feedline is installed in the water space near, but not touching, the
- A.
  
  Downcomer tubes
- B.
  
  Side of the drum
- C.
  
  Bottom of the drum
- D.
  
  Surface blowdown line
24.

Flat surfaces of a boiler are held in place by braces, which are called
- A.
  
  Baffles
- B.
  
  Tubes
- C.
  
  Stays
- D.
  
  Drums
25.

Water hammer in a piping sysytem is prevented by using
- A.
  
  Open traps
- B.
  
  Flash tanks
- C.
  
  Saturated pressure
- D.
  
  Pressure release valves