Ac333 Practice Questions

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AC333 Practice Questions

  
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  • 1. 
    The resistance wire often used in an electric heating element is made of:
    • A. 

      Copper.

    • B. 

      Stainless steel.

    • C. 

      Nickel chromium.

    • D. 

      Magnesium


  • 2. 
    Radiant heat is transferred by:
    • A. 

      Ultraviolet rays.

    • B. 

      Infrared rays.

    • C. 

      Ionization.

    • D. 

      Diffraction


  • 3. 
    Most electric baseboards units are _________
    • A. 

      Natural-draft convection

    • B. 

      Forced-draft convection

    • C. 

      Forced-draft conduction

    • D. 

      Radiant


  • 4. 
    Central forced-air electric furnaces frequently use _________ to start and stop multiple heating circuits.
    • A. 

      Capacitors

    • B. 

      Sequencers

    • C. 

      Limit controls

    • D. 

      Cool anticipators


  • 5. 
    A sequencer utilizes a _________ to initiate its operation.
    • A. 

      Bimetal heat motor

    • B. 

      Bimetal snap disc

    • C. 

      Capacitor

    • D. 

      Nichrome resistor


  • 6. 
    The component located in the thermostat that shuts the electric furnace down prematurely so that the space will not be overheated is the:
    • A. 

      Sequencer.

    • B. 

      Cool anticipator.

    • C. 

      Heat anticipator.

    • D. 

      Mercury bulb.


  • 7. 
    The disadvantage in using a contactor to open and close the circuit to the electric heating elements is the:
    • A. 

      Noise it makes.

    • B. 

      Low-control voltage.

    • C. 

      Heating elements would all be started at the same time unless separate time delay relays were used.

    • D. 

      Both A and C.


  • 8. 
    A limit switch or control is used to:
    • A. 

      Start the furnace if the thermostat malfunctions.

    • B. 

      Ensure that the fan stops when the furnace cools down.

    • C. 

      Starts the furnace prematurely on a cold day.

    • D. 

      Open the circuit to the heating elements if the furnace overheats.


  • 9. 
    Electric unit heaters are usually installed:
    • A. 

      Hanging from the ceiling.

    • B. 

      As baseboard heat.

    • C. 

      As forced-air furnaces.

    • D. 

      For hot water systems.


  • 10. 
    Electric ceiling panel heat:
    • A. 

      Easily adapts to central air conditioning.

    • B. 

      Is radiant-type heat.

    • C. 

      Uses circulating hot water.

    • D. 

      Can easily have humidity equipment added to the system.


  • 11. 
    The _____________ thermostat is commonly used for forced-air electric furnace installations.
    • A. 

      Low-voltage

    • B. 

      All-voltage

    • C. 

      No-voltage

    • D. 

      High-voltage


  • 12. 
    The _____________ thermostat is commonly used for baseboard electric heat installations.
    • A. 

      Low-voltage

    • B. 

      All-voltage

    • C. 

      No-voltage

    • D. 

      High-voltage


  • 13. 
    The control voltage for the controls on a sequencer are typically:
    • A. 

      24 V.

    • B. 

      208 V.

    • C. 

      460 V.

    • D. 

      12 V.


  • 14. 
    An electric furnace is operating on 225 V and is drawing 83 amps.  What heat capacity is this furnace putting out?
    • A. 

      55,787 Btu/h

    • B. 

      33,467 Btu/h

    • C. 

      98,953 Btu/h

    • D. 

      63,738 Btu/h


  • 15. 
    Radon is a(an):
    • A. 

      Radioactive gas.

    • B. 

      Refrigerant used for special systems.

    • C. 

      Oil additive.

    • D. 

      Filter media.


  • 16. 
    Formaldehyde byproducts may be found in:
    • A. 

      Old fruits and vegetables.

    • B. 

      Aerosols.

    • C. 

      Cleaning supplies.

    • D. 

      Pressboard and carpets.


  • 17. 
    Dust mites are:
    • A. 

      Usually found in damp areas in basements.

    • B. 

      Often found in dust blown through vacuums with HEPA filters.

    • C. 

      Microscopic spider-like insects.

    • D. 

      Related to mold spores.


  • 18. 
    Mold:
    • A. 

      Is usually found in dusty, dry areas.

    • B. 

      Is usually found in areas where there is moisture and/or high humidity.

    • C. 

      Is seldom found in areas where it can be seen.

    • D. 

      Spores are not harmful to humans.


  • 19. 
    The first step with regard to mold cleanup should be:
    • A. 

      Remove the source of moisture.

    • B. 

      Vacuum the area.

    • C. 

      Check for radioactive activity.

    • D. 

      Check the filter media in the area.


  • 20. 
    Carbon monoxide:
    • A. 

      Has a bluish color.

    • B. 

      Can easily be seen.

    • C. 

      Is heavier than air.

    • D. 

      Is produced by incomplete combustion in appliances that use the combustion process.


  • 21. 
    Auto exhaust produces carbon monoxide.
    • A. 

      True

    • B. 

      False


  • 22. 
    Wood smoke may contain:
    • A. 

      Polycyclic organic matter.

    • B. 

      Nonpolycyclic organic matter.

    • C. 

      Particles from combustion.

    • D. 

      All of the above.


  • 23. 
    Disturbed materials containing asbestos:
    • A. 

      Should be brushed down and swept up by the HVAC technician.

    • B. 

      Should be removed by a certified or licensed contractor.

    • C. 

      May be removed when found as part of a mold remediation program.

    • D. 

      Should be vacuumed up when found.


  • 24. 
    Ventilation is:
    • A. 

      A problem to deal with.

    • B. 

      Generally not recommended.

    • C. 

      Never used in a residence.

    • D. 

      The process of supplying or removing air by natural or mechanical means.


  • 25. 
    Duct cleaning is accomplished by:
    • A. 

      Polishing the outside of the duct.

    • B. 

      Washing out with with a hose and water.

    • C. 

      Using compressed air.

    • D. 

      Using a vacuum system and brushing.


  • 26. 
    All humidifiers must:
    • A. 

      Be installed correctly.

    • B. 

      Be serviced regularly.

    • C. 

      Use good water.

    • D. 

      All of the above.


  • 27. 
    Air in homes tend to be drier in the:
    • A. 

      Summer.

    • B. 

      Winter.


  • 28. 
    If the relative humidity is 60%, it means that:
    • A. 

      40% of air is moisture.

    • B. 

      60% of the air is moisture.

    • C. 

      The air has 60% of the moisture it has the capacity to hold.

    • D. 

      The air has 40% of the moisture it has the capacity to hold.


  • 29. 
    Humidification generally relates to a process of causing water to ________ into the air:
    • A. 

      Condense

    • B. 

      Evaporate

    • C. 

      Be ionized

    • D. 

      Be filtered


  • 30. 
    Infrared humidifiers reflect infrared energy:
    • A. 

      Into the air.

    • B. 

      Onto water.

    • C. 

      Onto an evaporative media.

    • D. 

      Into a hydronic boiler.


  • 31. 
    A humidistat has ________ element and is generally used to control a humidifier.
    • A. 

      A moisture-sensitive

    • B. 

      A light-sensitive

    • C. 

      An infrared-sensing

    • D. 

      An air pressure-sensing


  • 32. 
    Atomizing humidifiers discharge ________ into the air.
    • A. 

      Water vapor

    • B. 

      Electronic ions

    • C. 

      Trivalent oxygen

    • D. 

      Tiny water droplets


  • 33. 
    Two types of atomizing humidifiers are the:
    • A. 

      Thermistor and ionization generator.

    • B. 

      Spray nozzle and centrifugal.

    • C. 

      Disc and drum types.

    • D. 

      Particulate and oxidation types.


  • 34. 
    If reservoir-type humidifiers are not properly maintained, which of the following may collect and be discharged into the air?
    • A. 

      Fungi

    • B. 

      Bacteria

    • C. 

      Algae

    • D. 

      All of the above


  • 35. 
    In the ionizing section of an electronic air cleaner, the particles in the air are:
    • A. 

      Trapped by a filter.

    • B. 

      Charged with an electrical charge.

    • C. 

      Washed with a special cleaner.

    • D. 

      Treated to remove many of the odors.


  • 36. 
    Extended surface filters often use ________, which provides air cleaning efficiencies up to three times greater than those of fiberglass.
    • A. 

      Trivalent oxygen

    • B. 

      Charcoal

    • C. 

      Stainless steel

    • D. 

      Nonwoven cotton


  • 37. 
    Typically, air-conditioning (cooling) systems require an airflow of ________ cfm per ton.
    • A. 

      200

    • B. 

      400

    • C. 

      600

    • D. 

      800


  • 38. 
    If air conditioning is added to a heating system, the supply duct should be insulated to keep it from sweating and to keep the air in the duct from ________ in the cooling season.
    • A. 

      Absorbing heat

    • B. 

      Giving up heat

    • C. 

      Becoming too dry


  • 39. 
    A heating system typically requires ________ a cooling system.
    • A. 

      Less airflow than

    • B. 

      Greater airflow than

    • C. 

      About the same airflow as


  • 40. 
    In evaluating an air distribution system, the terminal units called the ________ are an important factor.
    • A. 

      Electric baseboard heaters and radiators

    • B. 

      Evaporator and condenser

    • C. 

      Grilles and registers

    • D. 

      Blower and damper


  • 41. 
    When two low-voltage transformers are wired in parallel, care must be taken to ensure that they are wired:
    • A. 

      In phase.

    • B. 

      In a circuit with the same resistance

    • C. 

      So that they produce the same amperage.


  • 42. 
    When adding an air-conditioning system to an existing furnace, frequently a ________ must be added to the control circuits.
    • A. 

      Thermocouple and limit switch

    • B. 

      Glow coil and static pressure disc

    • C. 

      Transformer and fan relay

    • D. 

      Stack switch and cad cell


  • 43. 
    When designing an all-weather system, the ductwork is designed around ________ system.
    • A. 

      The cooling

    • B. 

      The heating

    • C. 

      Either the heating or cooling


  • 44. 
    Too much airflow across the heat exchanger in a gas or oil heating system can cause ________ problems.
    • A. 

      Venting

    • B. 

      Poor combustion

    • C. 

      Intermittent ignition

    • D. 

      Flame retention


  • 45. 
    When adding a control transformer for air conditioning to an existing heating system, the second transformer can be wired in parallel with the original or:
    • A. 

      In a series with the original.

    • B. 

      As a separate circuit.

    • C. 

      In a parallel with the fan relay.

    • D. 

      In a parallel with the compressor contactor.


  • 46. 
    You need to install a 3-ton air-conditioning system on an existing furnace.  Using the chart in the text, Figure 42-4, which of the following will meet the fan needs?
    • A. 

      ¼ HP and a fan wheel that is 10" in diameter and 8" wide.

    • B. 

      ⅓ HP and a fan wheel that is 10" in diameter and 8" wide.

    • C. 

      ⅓ HP and a fan wheel that is 9" in diameter and 9" wide.

    • D. 

      ¼ HP and a fan wheel that is 9" in diameter and 8" wide.


  • 47. 
    A 2½-ton cooling system must circulate approximately __________ cfm of air.
    • A. 

      800

    • B. 

      1000

    • C. 

      1400

    • D. 

      2000


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