Final Exam Review

HEPA filters can filter to a very high efficiency - down to a(n) _____ micrometers sized particles or lower.

0.03

Slant coils for downflow application are designed with a coil slant of _____°.

60

The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has guidelines governing indoor air quality. These guidelines are called ASHRAE Standard _____.

62-2001

_____ filers have large surface areas and require a deep filter case.

Cube

If the wet-bulb and dry-bulb temperature are both 80°F, what is the humidity? a. 0% b. 50% c. 75% D. 100%

D. 100%

True or False During operation, the compressor motor will rotate in the opposite direction to change the direction of refrigerant flow.

False

True or False In a heat pump system, the indoor and outdoor coils are almost the same size.

False

True or False Introduction of forced ventilation in the winter heating season helps to raise the humidity level.

False

True or False It is common for the outdoor unit to ice-up when the heat pump is operated in the cooling mode.

False

True or False Leaks in all-aluminum coils are easier to repair than the standard copper tube-aluminum fin coil

False

True or False People who are active and spend a great seal of time outdoors are more likely to experience the effects of pollution.

False

True or False TXVs used in air conditioning units and heat pumps are interchangeable as long as they are the same size and for the same refrigerant.

False

True or False The all-aluminum coil has a higher heat transfer rate than the standard copper tube-aluminum fin coil.

False

True or False The return duct portion of an air handling system never needs to be insulated.

False

True or False When a compressor is changed, the four-way valve also must be changed.

False

True or False A humidifier should cycle with the blower in the heating unit.

True

True or False Caution must be used with changing from one filter type to another. If a technician installs a high density filter in the application, it is very likely that the air flow will be reduced because the same filter area is used with a more dense filter.

True

True or False Equipment will perform at it's best efficiency when running at full load.

True

True or False If a residential split air conditioning system has a compressor equipped with a start capacitor and relay, it is probably using a thermostatic expansion valve as a metering device.

True

True or False In the emergency heat mode, the auxiliary heat source becomes the primary heat source and the compressor is disabled.

True

True or False The air conditioning system is responsible for controlling the humidity inside a structure.

True

True or False The human body is comfortable when the heat produced in the body is equal to the heat lost to the surroundings.

True

True or False The main purpose of adding a humidifier to a heating system is to replace the moisture that is removed by the heating equipment.

True

True or False The rate at which water will evaporate from the wick on the wet-bulb thermometer is determined by the moisture content of the surrounding air.

True

True or False The supply duct portion of an air handling system need to be insulated when run through an unconditioned space.

True

True or False When brazing a four-way valve, heat absorbing paste should be placed around the body of the valve to minimize the chance of internal damage to the valve.

True

True or False The humidity difference in the 2 different locations (different parts of the county) must be accounted for in the condition equipment choice.

True

What is the recommended maximum number of grains per pound of material in the water supplied to an atomizing humidifier? a. 10 b. 50 c. 100 d. 125

a. 10

What is the relative humidity if the dry-bulb temperature is 100°F and the wet-bulb temperature is 65°F? a. 13% b. 33% c. 43% d. 63%

a. 13%

If the dry-bulb temperature is 93°F and the wet- bulb temperature is 60°F, what is the specific volume of the air? a. 14.0 ft3/lb b. 14.0 lb/ft3 c. 10 lb/ft3 d. 10 ft3/lb

a. 14.0 ft3/lb

What is the dew-point temperature if the wet-bulb temperature is 65°F and the dry-bulb temperature is 100°F? a. 40°F b. 50°F c. 60°F d. 70°F

a. 40°F

What prevents cold air from being circulated to the heated space during the defrost cycle? a. The auxiliary heater turns on the "temper" the air. b. All of the dampers close automatically. c. The indoor fan motor turns off. d. Both a and b are correct.

a. The auxiliary heater turns on the "temper" the air.

Comfort can be described as the gentle balance between ___. a. air cleanliness, air movement, temperature, and humidity b. air velocity, air cleanliness, humidity, and air movement c. air speed, air velocity, temperature, and humidity d. acceleration, air cleanliness, filtration, and humidiy

a. air cleanliness, air movement, temperature, and humidity

One of the most common substances that is used as an absorber is ___. a. charcoal b. silica gel c. Fiberglas d. foam rubber

a. charcoal

The generalized comfort chart can be used as a basis to ___. a. determine combinations of temperature and humidity to produce comfort in summer and winter b. study are and its properties c. determine the amount of fresh air make up necessary for comfort d. none of the above

a. determine combinations of temperature and humidity to produce comfort in summer and winter

The ___ is used to switch the unit between the heating and cooling modes of operation. a. four-way valve b. bi-valve c. two-way valve d. switching valve

a. four-way valve

A fiberglass filter media air filter contains a dust-holding adhesive that helps prevent particulates from ___. a. migrating downstream b. migrating upstream c. absorbing odors d. releasing spores

a. migrating downstream

The controller for a humidifier, a humidistat, has a power element that is ___ sensitive. a. moister b. light c. infrared d. temperatre

a. moister

The wet-bulb depression is ___. a. the difference between the dry-bulb and wet-bulb temperatures b. the same as the wet-bulb temperatures c. the same as the dry-bulb temperatures d. when the are is saturated with moisture

a. the difference between the dry-bulb and wet-bulb temperatures

The term _____ indicates the source of heat while the system is operating in the heating mode and the medium that is ultimately being treated.

air-to-air

If a heat pump is not capable of handling the heat load, a(n) _____ heat source will be added to help handle the load.

auxiliary

In the air-to-air heat pump system, the help that the heat pump gets is called _____ _____.

auxiliary heat

Infiltration is the term used when referring to the air entering a structure ___. a. through an air make-up unit b. around doors and windows c. through ventilation d. because of street traffic

b. around doors and windows

The air temperature of the air off an evaporative cooler is ___. a. warmer than the entering air b. cooler than the entering air c. the same as the entering air d. made up of sensible heat only

b. cooler than the entering air

Humidification generally relates to the process of causing water to ___ into the air. a. condense b. evaporate c. be ionized d. be filered

b. evaporate

High efficiency condensers ___. a. can withstand higher pressures than standard condensers b. have more surface area than standard condensers c. have stainless steel coils d. are located in separate cabinets

b. have more surface area than standard condensers

On a split air conditioning system with a remote condensing unit, which refrigerant lines must be field installed? a. discharge and suction b. liquid and suction c. discharge and liquid d. No lines need to be installed

b. liquid and suction

A dirty condenser coil can lead to ___. a. increased efficiency b. reduced efficiency c. increased head temperature d. increased subcooling

b. reduced efficiency

An air-to-air heat pump ___ heat from the outside air and deposits it in the conditioned space. a. adds b. removes c. creates d. restricts

b. removes

When exposed to salt air, ___ should be used for the screws to secure the sheet metal of cabinets of air conditioning equipment. a. copper b. stainless steel c. iron d. tin

b. stainless steel

The dew-point temperature is the ___. a. temperature when the air is saturated with moisture b. temperature when the moisture begins to condense out of the air c. difference between the dry-bulb and wet-bulb temperatures d. temperature of the air at 50 % relative humidity

b. temperature when the moisture begins to condense out of the air

More than one evaporator coil circuit is used when ___. a. the evaporator is located outside the conditioned area b. there would be excessive refrigerant pressure drop in the coil circuit c. a distributor would not be practical d. a slant coil is at an angle more than 60°

b. there would be excessive refrigerant pressure drop in the coil curcuit

When the heat pump is supplying as much heat as the load requires and is operating continuously, it is at what is called the _____ _____.

balance point

When electric auxiliary heat is used with a pump, the best location of the inside coil is _____ the auxiliary heat unit.

before

A(n) _____ thermostatic expansion valve has a check valve built into the body of the TXV.

bi-directional

What are the relative humidity limits recommended for residences? a. 20% to 40% b. 30% to 50% c. 40% to 60% d. 50% to 70%

c. 40% to 60%

Termination of the defrost cycle occurs when the liquid off the outside coil reaches ___. a. 35°F b. 45°F c. 50°F d. 65°F

c. 50°F

A popular material combination used in air conditioning evaporators and condensers is ___. a. copper tube-stainless steel fin b. copper tube-copper fin c. copper tube-aluminum fin d. aluminum tube-aluminum fin

c. copper tube-aluminum fin

A pressure augmented defrost control is activated by the ___. a. difference of the pressure in the fan compartment and the temperature of the coil. b. difference in pressure between the outdoor pressure and the fan discharge pressure c. difference in the pressure of the air through the outdoor coil d. difference in pressure of the refrigerant in the condenser and the pressure of the coil

c. difference in the pressure of the air through the outdoor coil

The solar load on a structure is the heat gain resulting from the ___. a. heat from the surrounding air conducted through the materials of the structure b. air infiltration from the sun c. heat from the radiation from the sun d. dry-bulb inside the structure

c. heat from the radiation from the sun.

The total heat content of infiltrated air of the same dry-bulb temperature may vary from one part of the country to another because of the difference in ___. a. solar load b. sensible heat c. humidity d. convection currents

c. humidity

A homeowner plans to build a house out in Las Vegas, Nevada in the middle of the desert. It would be in his/her best interest to lower the "solar load," to locate most of the windows on the ___. a. north and east sides of the house b. east and west sides of the house c. north and south sides of the house d. south and west sides of the house

c. north and south sides of the house

A fresh air intake is necessary to keep the indoor air from becoming ___. a. too humid b. superheated c. oxygen starved and stagnant d. too dry

c. oxygen starved and stagnant

The dry-bulb temperature is the ___. a. same as the wet-bulb temperature b. total of the sensible and latent heat c. sensible heat level of the air d. sensible heat less the humidity

c. sensible heat level of the air

The wet-bulb temperature ___. a. is the same as the wet-bulb depression b. is the saturation pressure c. takes into account the moisture content of the air d. is always higher than the dry-bulb temperature

c. takes into account the moisture content of the air

The density of air is the ___. a. amount of moisture in the air b. amount of movement in the air per cubic foot c. weight of the air per cubic foot d. combination of the temperature and pressure of the air

c. weight of the air per cubic foot

In reciprocating and scroll type motor-compressor assemblies, the motor is cooled by ___. a. air over the shell of the assembly b. discharge gas from the compressor c. suction gas returning to the compressor d. liquid refrigerant by-passed from the liquid line.

c.suction gas returning to the compressor

The two types of atomizing humidifies are the spray nozzle and _____

centrifugal

To remove odors, downstream from air filters, a filter using a materiel called _____ is used.

charcoal

When odor is a concern, a filter containing _____ should be used.

charcoal

In the ionizing section of an electronic air cleaner, the particles in the air are given a(n) _____.

charge

The component of the air-to-air heat pump component that is the outdoor unit is known as the _____. (when in cooling mode)

condenser

The indoor coil acts as the evaporator in the summer and the _____ in the winter

condenser

The density of water is ___. a. 61.3 lb/ft3 b. 62.0 lb/ft3 c. 62.3 lb/ft2 d. 62.3 lb/ft3

d. 62.3 lb/ft3

On a package air conditioning system, which refrigerant lines must be field installed? a. discharge and suction b. liquid and suction c. discharge and liquid d. No lines need to be installed

d. No lines need to be installed.

Electronic air cleaners generally have ___. a. ionizing sections b. charcoal filters c. pre-filters d. all of the above

d. all of the above

If reservoir-type humidifiers are not properly maintained, which of the following can be discharged into the air? a. fungi b. bacteria c. algae d. all of the above

d. all of the above

The steps to aggressively controlling the contamination of indoor air would involve ___ . a. locating and eliminating the source of contamination b. providing adequate ventilation c. providing methods for cleaning the air d. all of the above

d. all of the above

A house is built on property whose soil is rich in uranium. The occupants of the house may ___. a. be exposed to radon gas b. be more susceptible to lung cancer c. smell the pungent odor of the radon d. both a and b.

d. both a and b.

An extended surface filter (pleated type) ___. a. does not clog up as quickly as a standard filter b. is able to remove more dirt since the surface area is larger c. costs less than a standard filter d. both a and b.

d. both a and b.

In rotary type motor-compressor assemblies, the motor is cooled by ___. a. air over the shell of the assembly b. discharge gas from the compressor c. suction gas returning to the compressor d. liquid refrigerant by-passed from the liquid line.

d. discharge as from the compressor

Of the heat produced in the human body, which is by perspiration? a. conduction b. convection c. radiation d. evaperation

d. evaperation

The suction line is known as the ___ line in an air-to-air heat pump split system. a. vapor b. liquid c. transient d. gas

d. gas

The small line in an air-to-air split system heat pump is known as the ___ line. a. gas b. vapor c. solid d. liquid

d. liquid

The main valve in a pilot-operated four-way reversing valve is moved by pressure created by ___. a. refrigerant boiling in the coil b. pressure reduction in the condenser c. change in the action of the metering device d. low and high side pressure difference

d. low and high side pressure difference

the package air-conditioning system is ___ than the split system because it is completely factory assembled and charged with refrigerant. a. less efficient b. slightly less efficient c. slightly more efficient d. more efficient

d. more efficiant

Atomizing humidifier discharge ___ into the air. a. CO2 b. electronic ions c. carbon dioxide d. tiny water droplets

d. tiny water droplets

The efficiency of a heat pump operating in the heat mode tends to _____ as the outside air temperature drops.

decrese

When oil or gas auxiliary heat is used with a heat pump, the heat pump coil must be located in the _____ of the furnace.

downstream

When an "A" coil is used in a horizontal application, the coil is laid on its side and a special _____ is required.

drainpan

For high-efficiency fossil fuel and electronic furnaces as well as heat pump systems, the recommended humidifier would be a(n) _____ _____ type.

electrically heated

The component of the air-to-air heat pump component that is the indoor unit is known as the _____. (when in cooling mode)

evaporater

The _____ _____ _____ is a four-port valve that has a slide mechanism in it.

four-way reversing valve

The coil that serves the inside of the house in a heat pump is known as the _____ _____.

indoor coil

There are two kinds of attic ventilation, power and ______.

natural

Three types of expansion devices are used in residential air conditioning systems. They are TXV, capillary tube, and _____ .

orifice

In time-temperature defrost controls, the temperature that actuates the control is the temperature of the _____ _____.

outside coil

A compressor that uses a stationary vane is the _____ type.

rotary

Environmental tobacco smoke (ETS) is more commonly known as _____ _____.

secondhand smoke

When thermostatic expansion valves are used on heat pump systems, _____ _____ thermal bulbs are most common in order to prevent the valve's diaphragm from rupturing.

vapor charge or limited charge or critically charge