Ac333 Practice Questions

1. The control voltage for the controls on a sequencer are typically:

24 V.

208 V.

460 V.

12 V.

2. Auto exhaust produces carbon monoxide.

True

False

3. Disturbed materials containing asbestos:

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

Should be removed by a certified or licensed contractor.

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

Should be vacuumed up when found.

4. Ventilation is:

A problem to deal with.

Generally not recommended.

Never used in a residence.

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

5. Mold:

Is usually found in dusty, dry areas.

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

Is seldom found in areas where it can be seen.

Spores are not harmful to humans.

6. The first step with regard to mold cleanup should be:

Remove the source of moisture.

Vacuum the area.

Check for radioactive activity.

Check the filter media in the area.

7. All humidifiers must:

Be installed correctly.

Be serviced regularly.

Use good water.

All of the above.

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

Fungi

Bacteria

Algae

All of the above

9. Air in homes tend to be drier in the:

Summer.

Winter.

10. The _____________ thermostat is commonly used for forced-air electric furnace installations.

Low-voltage

All-voltage

No-voltage

High-voltage

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

A moisture-sensitive

A light-sensitive

An infrared-sensing

An air pressure-sensing

12. Carbon monoxide:

Has a bluish color.

Can easily be seen.

Is heavier than air.

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

13. Radon is a(an):

Radioactive gas.

Refrigerant used for special systems.

Oil additive.

Filter media.

14. Duct cleaning is accomplished by:

Polishing the outside of the duct.

Washing out with with a hose and water.

Using compressed air.

Using a vacuum system and brushing.

15. Humidification generally relates to a process of causing water to ________ into the air:

Condense

Evaporate

Be ionized

Be filtered

16. A limit switch or control is used to:

Start the furnace if the thermostat malfunctions.

Ensure that the fan stops when the furnace cools down.

Starts the furnace prematurely on a cold day.

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

17. Wood smoke may contain:

Polycyclic organic matter.

Nonpolycyclic organic matter.

Particles from combustion.

All of the above.

18. Electric ceiling panel heat:

Easily adapts to central air conditioning.

Is radiant-type heat.

Uses circulating hot water.

Can easily have humidity equipment added to the system.

19. 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.

Absorbing heat

Giving up heat

Becoming too dry

20. Radiant heat is transferred by:

Ultraviolet rays.

Infrared rays.

Ionization.

Diffraction

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

Capacitors

Sequencers

Limit controls

Cool anticipators

22. Dust mites are:

Usually found in damp areas in basements.

Often found in dust blown through vacuums with HEPA filters.

Microscopic spider-like insects.

Related to mold spores.

23. The resistance wire often used in an electric heating element is made of:

Copper.

Stainless steel.

Nickel chromium.

Magnesium

24. Most electric baseboards units are _________

Natural-draft convection

Forced-draft convection

Forced-draft conduction

Radiant

25. Two types of atomizing humidifiers are the:

Thermistor and ionization generator.

Spray nozzle and centrifugal.

Disc and drum types.

Particulate and oxidation types.

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

200

400

600

800

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

Sequencer.

Cool anticipator.

Heat anticipator.

Mercury bulb.

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

Noise it makes.

Low-control voltage.

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

Both A and C.

29. In the ionizing section of an electronic air cleaner, the particles in the air are:

Trapped by a filter.

Charged with an electrical charge.

Washed with a special cleaner.

Treated to remove many of the odors.

30. The _____________ thermostat is commonly used for baseboard electric heat installations.

Low-voltage

All-voltage

No-voltage

High-voltage

31. If the relative humidity is 60%, it means that:

40% of air is moisture.

60% of the air is moisture.

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

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

32. A heating system typically requires ________ a cooling system.

Less airflow than

Greater airflow than

About the same airflow as

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

800

1000

1400

2000

34. Infrared humidifiers reflect infrared energy:

Into the air.

Onto water.

Onto an evaporative media.

Into a hydronic boiler.

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

Thermocouple and limit switch

Glow coil and static pressure disc

Transformer and fan relay

Stack switch and cad cell

36. Atomizing humidifiers discharge ________ into the air.

Water vapor

Electronic ions

Trivalent oxygen

Tiny water droplets

37. Formaldehyde byproducts may be found in:

Old fruits and vegetables.

Aerosols.

Cleaning supplies.

Pressboard and carpets.

38. Electric unit heaters are usually installed:

Hanging from the ceiling.

As baseboard heat.

As forced-air furnaces.

For hot water systems.

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

In phase.

In a circuit with the same resistance

So that they produce the same amperage.

40. 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:

In a series with the original.

As a separate circuit.

In a parallel with the fan relay.

In a parallel with the compressor contactor.

41. When designing an all-weather system, the ductwork is designed around ________ system.

The cooling

The heating

Either the heating or cooling

42. 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?

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

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

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

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

43. A sequencer utilizes a _________ to initiate its operation.

Bimetal heat motor

Bimetal snap disc

Capacitor

Nichrome resistor

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

Electric baseboard heaters and radiators

Evaporator and condenser

Grilles and registers

Blower and damper

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

55,787 Btu/h

33,467 Btu/h

98,953 Btu/h

63,738 Btu/h

225 x 83 x 3.413 = 63,738

Explanation