AC Final Flashcards by Malachi Nokes

Comfort can be described as the gentle balance between ______.

a. temperature, humidity, air movement, and air cleanliness
b. air velocity, air cleanliness, humidity, and air movement
c. air speed, air velocity, temperature, and humidity
d. acceleration, air cleanliness, filtration, and humidity

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Of the heat produced in the human body, which is by perspiration?

a. Conduction
b. Convection
c. Radiation
d. Evaporation

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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 ft 3/lb
b. 14.0 lb/ft 3
c. 12.0 lb/ ft 3
d. 12.0 ft 3/ lb

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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 air and its properties
c. determine the amount of fresh air make up necessary for comfort
d. none of the above

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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 pressur of the air

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The density of water is _______.

a. 61.3 lb/ft 3
b. 62.0 lb/ft 3
c. 62.4 lb/ ft 2
d. 62.4 lb/ ft 3

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What is the relative humidity if the dry bulb temperature is 100 F and the wet bulb temperature is 62 F?

a. 13 %
b. 28%
c. 43%
d. 58%

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If the wet bulb and dry bulb are both 80 F what is the humidty?

a. 0%
b. 35%
c. 70%
d. 100%

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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

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The reading from a wet bulb thermometer ______.

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

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The wet bulb depression is ____.

a. the difference between dry and wet bulb temperatures
b. the same as the wet bulb temperatures
c. the same as the dry bulb temperatures
d. when the air is saturated with moisture

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What is the dew point temperature if the wet bulb temperature is 65 F and the dry bulb temperatures is 100 F.

a. 40 F
b. 50 F
c. 60 F
d. 70 F

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The dew point temperature is the _______.

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

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Infiltration is the term used when referring to the air entering a stucture _____.

a. through an air make up unit
b. around doors and windows
c. through ventilation
d. because of street traffic

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A small amount of air is induced from the outside into the conditioner to keep the air from becoming _______.

a. too humid
b. superheated
c. oxygen starved and stagnant
d. too dry

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T/F The human body is comfortable when the heat produced in the body is equal to the heat lost to the surroundings.

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T/F The rate at which water will evaporate from the wick on the wet bulb thermometer is determined b the moisture content of the surrounding air.

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T/F Introduction of forced ventilation in the winter heating season helps to raise the humidity level.

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The average core body temperature is ______ F.

98.6 F

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Typically when the body is at rest (sitting) and in surrounding of _______ F and 50% humidity with a slight air movement, the body is close to being comfortable.

75 F

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Air consists of approximately 78% ______, 21% oxygen and 1% other gases.

nitrogen

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Water in the form of low pressure vapor is suspended in the air and is called ______.

Humidity

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The mositure content in air (humidity) is measured by weight and expressed in pounds or ______.

Grains

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The closer the wet bulb and dry bulb temperature are to each other, the higher the ______.

relative humidity

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If the dry bulb temperature is 76 F and the wet bulb temperature is 68 F, the wet bulb depression is ______ F.

When the dry bulb and wet bub temperature are the same, the relative humidity of the air is ________.

100%

The ______ of air is the measure of heat content in Btu per pound of air.

Entholpy

When fresh air is introduced through the air handling system, the process is called fresh air intake, or _________.

Ventilaton

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

A homeowner plans to bulid 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 lacate most of the windows on the _____ sides of the house. a. north and east b. east and west c. north and south d. south and west

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 c. heat form the radiation of the sun d. dry bulb inside the sturcture

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 distrbutor would not be pratical d. a slant coil is at an angle more than 60 degrees

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. stainless steel tube aluminum fin

In reciprocating compressor used in air conditioning, the motor is mainly cooled by ______. a. air over the shell of the assembly b. discharge gas from the compressor c. suction gas returing to the compressor d. Both a and c

In rotary compressor, 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 passsed from the liquid line

A dirty condenser coil can lead to _______. a. increased efficiency b. reduced efficinency c. reduced head pressure d. increased subcooling

High efficiency condensers _______. a. cna withstand higher pressures than standard condensers b. have more surface area than standard condensers c. have stainless steel coil d. are located in serparate cabinets

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

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

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 to be field installed

Appearance is a major drawback with what type of air conditioning equipment? a. ductless split systems b. ground level package units c. rooftop package units d. multi position package units

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

T/F The moisture content of the air in different locations of the country must be taken into account when selecting air conditioning equipment.

T/F After being threaded many times the screw holes in condenser cabinets may become oersized if so replace the srews with new ones of the same size.

T/F If a structure has no attic, there should be sufficient sinsulation in the roof to minimize the heat gain in the occupied space.

T/F Air conditioning equipment will perform at its best effciency when running at full load.

T/F If a residential split air conditioning system has a compressor equipped with a start capacitor and relay, it is probably using a thermistatic expansion valve as a metering device.

T/F The supply duct portion of an air handling system needs to be insulated when run through an unconditioned space.

T/F The return duct portion of an air handling system never needs to be insulated.

There are three kinds of attic ventilation power, natural and _______.

solar

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

Condensation drain

Slant coils for downflow application are designed with coil slant of usually _______%.

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

rotary

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

Orifice

The pressure in a duct system is measured in ________. a. psig b. psia c. in Hg d. in WC

The ______ provides the pressure difference needed to force the air into the duct system, through the heat transfer surfaces in the conditioning equipment, through the grilles and registers, and into the room. a. blower b. forcer c. compressor d. condenser

The atmosphere exerts a pressure of ______ at standard atmospheric conditions. a. 12.696psi b. 14.696psi c. 16.696psi d. 18.696psi

A ____ can be connected to measure the velocity pressure of the air moving in a duct. a. ammeter b. manometer c. pyrometer d. speedometer

An instrument that is commonly used on air distribution systems is the anemometer or _____. a. velometer b. manometer c. pyrometer d. ammeter

Airflow pressure in ductwork is measured in inches of _______. a. mercury pressure b. water column c. air pressure d. mercury column

The simple way to check for airflow is to see if you cna feel the airflow at a distance of about ______ from each register. a. 2 to 3 feet b. 3 to 5 feet c. 5 to 8 feet d. 8 to 10 feet

The reason for using a reducing plenum system is to _______. a. reduce maintenance costs b. reduce the operating cost of the system c. provide easier means of fastening the takeoff fittings d. maintain a constant pressure throughout the length of the trunk duct

One reason for using an extended plenum system is to ____. a. save materials b. reduce the velocity of the air as the air reaches the a last takeoffs on the extended plenum c. prolong the main plenum closer to the farthest supply register d. keep the noise level low

A ______ F temperature difference from the inside to the outside of the duct is considered the amximum difference allowable before insulation is necessary. a. 10 b. 15 c. 18 d. 20

If the equivalent length of a transition piece of ductwork is 10 feet and the main duct is series with it is 20 feet, what is the length used to estimate the total frictional loss? a. 10 feet b. 20 feet c. 30 feet d. 60 feet

T/F The forced air system is different from a natural draft system, where the air passes naturally over the conditioning equipment.

T/F The duct pressure equals the velocity pressure plus staitc pressure.

T/F Adjusting the tension on the belt will alter the rate at which air is moving through the system but does not affect the amperage draw of the motor.

T/F Canvas collors are generally made of canvas rather than other materials such as rubber.

T/F Duct systems can be plenum, extended plenum, reducing plenum, or perimeter loop.

T/F Oversized duct systems cost more to fabricate and install and will also result in the slowing of the air as it flows through the duct.

T/F The main drawback of the extended plenum system is that the velocity of the air is lower as the air reaches the last takeoffs on the extended plenum.

T/F A device used to put trunk duct or extended plenum sections together is called a drive clip.

T/F Friction due to air rubbing the walls of the ductwork can be eliminated.

Baseboard hot water heat is an example of _______ heat.

radiant

Galvanized sheet metal comes in several different thicknesses, called the _______ of the metal.

gauge

Flexible round duct comes in sizes up to about ______ in in diameter.

Each foot of duct offers a known resistance to airflow which is called ______.

Friction loss

If the velocity of air through an 8 * 20 duct id 700 fpm, how many cfm of air is being carried by the duct?

777cfm

One drawback of using custom made, pre fabicated duct sections is that ______. a. if the measuring was not done correctly, the job may not go together b. altering a duct section at the job site results in lost time c. altering a duct section at the job site is extemely cost ineffective d. all of the above

What two fasters are used with sheet metal square and rectangular duct? a. s fasteners (slips) and drive clips b. staples and tape c. self tapping screws and draw bands d. tabs and adhesives

What fastener is commonly used with round flexible duct? a. s fasteners (slips) and drive clips b. staples and tape c. self tapping screws d. tabs and adhesives

What two fasteners are used with fiberglass ductboard? a. s fasteners (slips) and drive clips b. staples and tape c. self tapping screws and draw bands d. tabs and adhesives

_______ used at the end of a metal duct run will help reduce any noise that may be traveling through the duct. a. fiberglass ductboard b. aluminum duct c. insulated metal duct d. flexible duct

A boot in a duct system is a fitting used ________. a. at the plenum b. between the trunk duct and the branch duct c. between the branch and the supply register d. to eliminate vibration between the unit and the duct

A trap in the condensate line prevents _______. a. air from being drawn up into unit from the end of the drain b. foreign particles from being pulled into the condenser c. the pump turning on if the float fails d. both a and b

An auxiliary drain pan under the unti is recommended when the evaporator is installed ______. a. near a dry well b. at the end of the house c. above the conditioned space d. next to a driveway or patio

After refrigerant lines have been installed, they should be evacuated to a _______ vacuum. a. average b. low c. moderate d. deep

T/F One purpose of a flexible duct connector in a duct system is to reduce the transmission of noise and virbration.

T/F Application of acoustical lining to the interior of a duct is accomplished by using tabs, glue, or both.

T/F Power to the control trnasformer is controlled by the conditioned area thermostat.

T/F When hanging a horizontal air handler, it should be pitched toward the drain port for proper condensate.

T/F The sun shining on the panels and coils of the condensing section will lower the efficiency of the unit.

T/F When installing a split air conditioning system with a remote condensing unit, the line set may be altered if the standard length was incorrect for installation.

T/F When removing the rubber plugs from a line set, the hiss indicates that the tubing is not leaking.

T/F When the length of quick connect presharged line sets is altered, the charge will not normally have to be altered.

T/F Once the power has been connected to the condensing unit of a package air conditioner, it is a good idea to start the compressor immediately to make certain it runs.

A fitting used to change the size of a square or rectangular duct is called ______.

transistion

A round to rectanguar fitting is called a ________.

Square to round tansition

A split central air conditioning system is installed with the control trnasformer located in the attic hung air handler and the condensing unit located outside. The low voltage wire from the thermostat is run to the _________.

air handler

The typical gauge wire that is used in low voltage control circuits is _________ gauge.

Before a system is evacuated, all piping should be filled with nitrogen and a samm amount of refrigerant, in order to be _________ checked.

leak

Homeowner can cut utility bills by _______ % or more by following energy audit recommendations. a. 15 b. 20 c. 25 d. 30

According to the United States Department of Energy (US DOE) 43% of the energy used by the average home goes toward _____. a. heating water b. refrigeration c. space heating and space cooling d. lighting

The home's exterior is also known as the _______. a. core b. shell c. structure d. case

Flexible products made from mineral fibers, such as fiberglass and rock wool are known as ______. a. rigid fill insulation b. roll in place insulation c. loose fill insulation d. rolls and batts

The higher the ______ value, the better your walls and roof will resist the transfer of heat. a. S b. T c. P d. R

Cavity insulation can be installed at levels up to _______ in a 2 in * 4in wall. a. R-5 b. R-6 c. R-15 d. R- 21

________ streaks in a flame are dust particles burning. a. Yellow b. Orange c. Blue d. Red

______ is a colorless and oderless gas which can sicken or kill persons residing in the home. a. Hydrogen b. Nitrogen c. Carbon dioxide d. Carbon monoxide

A ____ furnace has a postive vent pressure and operates with a vent gas temperature at least 140 F above its dew point and is known as a mid efficiency furnace. a. Category I b. Category II c. Category III d. Category IV

_____ is the force that allows air to travel into the combustion chamber of a combustion appliance and force the combustion gasses out through a vent or chimney. a. Dampening b. Thrust c. Draft d. Force

______ draft is taken in the vent stack between the combustion device and the draft diverter. a. over the fire b. chimney c. vent d. combustion

_______ minimizes the interaction of the furnace with other combustion appliances. a. Heat venting b. Pressurized venting c. Indirect venting d. Direct venting

T/F The US DOE says that 12% of the home's total energy bills usually goes toward heating water for hosuehold use.

T/F The terms residential energy audit and home energy audit are often used interchangeably.

T/F Diagnostic testing and evaluation of the home and it systems is perhaps the least important phase of a residential audit.

T/F Numerical analysis and review of the homes energy consumption history, which will include both electrical and heating fuel bills is an important part of a residential audit.

T/F Sealing and insulating the envelope of shell of a home is often the most cost effective way to improve energy efficiency and comfort.

T/F Ventilation has little effect on moisture control.

T/F Adding insulation to the attic is fairly difficult but very cost effective.

T/F Gas equipment preventive maintenance consists of servicing the air side components: filter, blower, belt and drive, and the burner section.

T/F Cad cells or photo cells are usually used in conjunction with a primary control and are most often found on electric furnaces.

T/F Furnace manufacturers use standard pressure settings for their pressure switches.

T/F Making sure heating, cooling, refirgeration, water heating and humidification systems are all working properly and efficiently greatly affect the energy usage of the residence.

A preliminary evaluation of the homeowner's needs is known as _______.

home audit

A _______ Insulation Calculator tools can provides insulation levels for your news or existing home based on your zip code and other basic information about your home.

zip code

_________ spaces include the areas of the residence that are heated or cooled.

Conditioned

Low emittance is also referred to as low _____ factor.

emissinity

Measuring the total air duct leakage is accomplished with _________ test.

blower door

_______ draft is the draft taken over the fire.

Over fire

How is air leakage through the house's shell determined?

Infrade camera or blower door test

Most occupants will normally operate their system at about ______ 75F. a. 68 b. 72 c. 75 d. 80

AHRI rates condensers with _______F air passing over them. a. 70 b. 75 c. 85 d. 95

At what conditions are air conditioning system rated? a. 95 F outdoor 70 F DB and 50% indoors b. 95 F outdoor 75 F DB and 50% indoors c. 95 F outdoor 80 F DB and 50% indoors d. 100 F outdoors 80 F DB and 60% indoors

At typical operating conditions, the standard air conditioning system will operate with an evaporator boiling point of _____ F. a. 40 b. 45 c. 50 d. 55

A normal evaporator superheat at the evaporator outlet in a standard efficiency air conditioning system operating under design conditions will be _____ F. a. 10 b. 15 c. 20 d. 25

At typical operating conditions, the high efficiency air conditioning system will operate with an evaporator boiling point of _____ F. a. 40 b. 45 c. 50 d. 55

The _____ rating is a steady state rating and does not account for the time the unit operates before reaching peak efficiency. a. ARR b. SAR c. DER d. EER

Ratings that are not completely accurate are know as ______. a. load rating b. maximal ratings c. nominal ratings d. floor ratings

T/F Since the evaporator absorbs both sensible and latent heat, humidity must be taken into account and considered part of the load on the evaporator.

T/F High efficiency condensers can actually be too efficient on cold days.

T/F The larger the EER rating, the less efficient the equipment.

Typically, the fan will run on high speed when the outdoor temperature is above _____ F.

The evaporator ______ heat.

absorbs

The condenser _____ heat.

rejects

A 4 ton air conditioning system that requires an input power of 5 kw would have an energy efficiency ratio of ______.

1 ton = 12000 1 kw = 1000 48000/5000 = 9.6

The electrical operating conditions are measured with a voltohmmeter and a _______.

ammeter

For residential air conditioning units, _______ V single phase is the typical voltage.

230

Air conditioning systems normally move about _______ cfm of air per ton.

400

A four pole motor runs at ______ rpm.

1800

A two pole motor runs at ______ rpm.

3600

As a rule of thumb, the air leaving the evaporator will be about ____ than the air entering the evaporator. a. 10 - 15 warmer b. 10 -15 cooler c. 17 - 20 cooler d. 17 - 20 warmer

A service valve can be used to a. check the elctrical service to the compressor b. isolate the refrigerant so the system can be serviced c. check the air flow across the evaportor d. check the ambient temperature at the condenser

A typical evaporator superheat reading at the evaporator outlet for a central air conditioning system on a 95 F day would be _____F. a. 5-7 b. 8-10 c. 10-12 d. 12-15

On a 95 F day, the R-22 refrigerant pressure on the high side should be about ____ psig. a. 108 b. 182 c. 243 d. 297

The liquid line temperature is used to determine the ______ of a condenser. a. superheat b. lowside pressure c. suction pressure d. subcooling

To accurately add refrigerant to a system, a condenser ambient temperature of _______ F should be simulated. a. 75 b. 85 c. 95 d. 100

The instrument to use to check for a short in the compressor motor winding is a ______. a. ohmmeter b. ammeter c. voltmeter d. milliameter

T/F With a rise in outdoor temperature, the head pressure will rise

T/F The best way to tell if a compressor's discharge line is at the correct temperature is to grab hold of it.

T/F Subcooling occurs in the evaporator as well as the condenser.

T/F When checking the electrical circuits of an air conditioning system, wach parallel circuit should be isolated and checked separately

T/F If a compressor has a partially shorted winding, it could run for a while, overheat, and shut off.

Reducing the CFM through the evaporator will cause the head pressure to ______.

decrease

On most gauge manifolds, the suction or low side gauge is located on the _____.

left

Temperature difference is used to describe the difference in the inlet and ______ temperature of a heat exchanger.

outlet

Two types of fixed bore metering devices are capillary tubes and _______.

orifice

Reducing the CFM through the evaporator will cause the amperage draw of the compressor to _______.

decrease

Improper system balancing

Uneven cooling

Blocked/ dirty filter

low operating pressure and frozen evaporator coil

Defective evaporator fan motor

low operating pressure/ frozen evaporator coil

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

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

The main vavle in a pilot operated four way reversing valve is moved by pressure created by the 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

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

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

Termination of the defrost cycle by temperature occurs when the temperature sensor reaches a. 35 F b. 45 F c. 50 F d. 65F

A common method of starting defrost uses an air pressure switch that measures the difference in pressure a. between the fan compartment and the evaporator coil b. between the outdoor pressure and the fan discharge pressure c. of the air across the outdoor coil d. of the refrigerant in the condenser and the pressure in the coil

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

T/F When brazing a four way reversing valve, a wet rag could be wrapped around the body of the valve to minimize the chance of internal damage to the valve.

T/F During operation, the compressor motor will rotate in the opposite direction to change the direction of refrigerant flow.

T/F TXVs used in cooling only air conditioning units and heat pumps are interchangeable as long as they are the same size and for the same refrigerant.

T/F In the emergency heat mode, the auxiliary heat source becomes the primary heat source because of heat pump failure.

T/F It is common for the outdoor unit to ice up when the heat pump is operated in the cooling mode.

T/F When a compressor is changed, the four way valve also must be changed.

T/F The water to air heat pump might not need auxiliary heat because the water can be at relatively constant temperature all winter.

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

air to air

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

reversing valve

The coil of the air to air heat pump system that is the indoor unit is known as the ______ in the cooling mode.

evaporator

The coil of the air to air heat pump system that is the indoor unit is known as the _____ in the heating mode.

condenser

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

indoor coil

In heat pump system the sensing bulb is typically exposed to high temperature and could rupture the valve diaghragm. For this reason a _____ TXV is usually used.

vapor charged

A ______ thermostatic expansion valve has a check valve built into the body of the TXV.

bidirectial

Some heat pump systems when not capable of meeting the heating needs of the structure are equipped with second stage heat called _______.

auxiliary heat

Most heat pump systems are designed to operate in the heating mode when the solenoid is not energized. This is referred to as _______ in the heating mode.

failing

The lowest outside air temperature at which the heat pump system can satisfy the heating needs of the structure without requiring auxiliary heat is called the _________.

balance point

The coefficient of performance of a heat pump operating in the heat mode tends to ______ as the outside air temperature drops.

decrease

A common metering device is a combination flow device and check valve. This device is referred to as a ________.

piston

When a heat pump is added to an electric furnace, the indoor coil must be located after the ______ strips.

electric strips

In time temperature defrost controls, the temperature that actuates the control is the temperature of the _______ coil.

outdoor

When oil or gas auxiliary heat is used with a heat pump, the heat pump indoor coil must be located ________ of the oil or gas heat exchanger.

downstream

The most basic heat gain and heat loss calculations are based solely on the ____ of the space being conditioned. a. location b. height c. circumference d. area

As the _____ increases, the rate of heat transfer from one side of the structure to the other will increase. a. air temperature b. heat differential c. temperature d. temperature differential

One of the most commonly used characteristics of building construction materials is the _____ value. a. P b. T c. R d. Z

The _____ value is tpically used to rate the thermal resistance of insulation materials. a. P b. T c. R d. U

If the material has an R value of 30, then the orresponding U value will be _____. a. 0.033 b. 0.33 c. 33 d. 330

The net wall area can be expressed mathematically as _____. a. Gross wall area= Net wall area - door area + window area +area of other components b. Net wall area = gross wall area + door area + window area + area of the other components c. Net wall area = gross wall area - door area - window area - area of other components d. gross wall area + net wall area = door area - window area - area of other components

The heat transfer rate through a window is found through _____. a. Q = U + TD + area b. Q = U value + TD x area c. Q = U value x TD + area d. Q = u value x TD x area

Which of the values given below corresponds to a wall with the highest resistance to the pass of heat? a. R value = 0.80 b. U value = 1.50 c. U value = 0.80 d. R value = 1.00

For calculating the heat gain from the appliances, the guideline typically applied to a house with only a refrigertor and a vented cooking surfface is ______ Btu/h. a. 600 b. 1200 c. 2400 d. 3600

The term ______ is used to describe walls or portions of walls that are below ground level. a. under grade b. below grade c. level grade d. wall grade

The cfm is found by a. cfm = (ach / house volume) x 60 min/h b. cfm = (ach x house volume) / 60 min/h c. cfm = ( ach + house volume) / 60 min/h d. cfm = (ach x hosue volume) x 60 min/h

The sensible heat portion of the duct load can be calculated as ______. a. Q sensible duct load = envelope load + duct load factor/ duct insulation correction b. Q sensible duct load = envelope load x duct laod factor + duct insulation correction c. Q sensible duct load = envelope load x duct laod factor x duct insulation correction d. Q sensible duct load = envelope load/ duct load factor x duct insulation correction

T/F When it comes to sizing air conditioning and heating equipment bigger is definitely better

T/F Oversized air conditioning equipment will cool the space faster.

T/F The temperature on both sides of an exterior wall or panel is needed to help determine how much heat is entering or leveing the structure.

T/F Construction materials have a minor effect on the rate of heat transfer through the structural envelope.

T/F The total heat loss for a structure is simply the sum of the heat losses experienced by all of the construction elements that make up a particular structure.

T/F Very little heat lost through the roof

T/F The two important factors that affect the U value for the below grade portion of the wall are the materials used to construct the wall and how far below grade the floor is.

T/F THe total heat loss fot the basement walls is the product of the heat losses for the below grade and above grade walls.

T/F The heat gain on a structure can be summarized as the sum of the conduction loads, the internal loads, the solar loads and the infiltration loads.

T/F There are different methods to calculate the heat gain on a structure based on the type of house and the number of wall exposures it has.

T/F The occupants of a house do not add to the heat gain of the structure.

The ______ value describes the thermal conductivity of a material.

The U value and the ______ are inverses of each other.

R value

The walls of a structure make up a large portion of the ______ or shell of the structure.

envelope

Probably the easiest way to determine what size lumber was used to frame a house is to inspect the _______.

blueprint

_________ walls are walls that separate a conditioned interior space from an unconditioned interior space.

Partition

The _______ is simply the sum of the individual heat losses of the structure.

envelope load

The term that is used to describe the area of a wall before any doors or windows are cut into it is _________.

gross wall area

Many coaxial heat exchangers are made of ________. a. steel b. aluminum c. nickel d. cupronickel

What is the temperature differential between water in and water out of a heat exchanger that has transferred 50,000 Btu/h? The flow rate is 10 gallons per minute. a. 5 b. 10 c. 20 d. 50

When the water and refrigerant in a heat exchanger flow in opposite directions, it is referred to as _____. a. countersink b. parallel flow c. conter flow d. bias flow

In a closed loop system the plastic water pipes that are buried in the earth are called. a. ground loops b. thermal loops c. water loops d. both a and c

The hot gas line from the heat pumps compressor can be used to ______. a. cool down the condenser b. heat domestic water c. keep the well water from freezing d. both a and c

An advantage of a series flow configuration of ground loops is ________. a. smaller diameter pipes b. ease of removing trapped air c. simplified flow path d. higher heat transfer per foot

T/F Since the earths crust is cooler than the air during the summer, it can be used to accept air conditioning heat loads.

T/F Temperature, quantiy, and cleanliness are three important factors that should be addressed when referring to water quality.

T/F In a closed loop system, the same fluid will absorb heat from the ground in the winter and reject the heat to the ground in the summer.

T/F In a gothermal heat pump system, there is a refrigerant loop and water loop.

T/F A domestic hot water loop is often used for heating domestic hot water from the hot discharge gas coming from the heat pump's refrigerant compressor.

T/F In order to prevent water contamination, wells used for geothermal heat pump systems are grouted.

T/F Scale results in a low heat pressure in the cooling mode and high suction pressure in the heating mode.

T/F One of the minor differences between troubleshooting a geothermal heat pump and an air to air heat pump is how to gain access to pressures and temperature in the water or ground loop.

Geothermal heat pump use the ______ water as a heat source or a heat sink.

earths

Closed loop or _____ systems reuse the same heat transfer fluid, which is circulated in buried plastic pipes within the earth or within a lake or pond.

earth loop

Open loop water source heat pump systme involve the transfer of heat between a water source and the air or water being circulated to a ______ space.

conditioned

The inner tube of heat exchangers or water source heat pumps heave extended surfaces called _____, which increase the surface area for better heat transfer.

leads

The inner tube of heat exchangers or water source heat pumps heave extended surfaces called _____, which increase the surface area for better heat transfer.

leads

Before deciding to purchase or install an open loop system , the _____ must be evaluated first.

water quality

A ______ blower is used to move the air through the air distribution system.

squriell cage

The ground loop configuration that is used when there is a shortage of land is the ______.

vertical

Three common types of antifreeze are salts, gycols and _______.

alcohols

A dedicted geothermal well is part of a _______ system.

closed

A dry well is most commonly usedd as part of a ______ system.

open

________ heat pumps utilize two coaxial heat exchangers, as compared to only one on the water to air configuration.

Water to water

The ______ is nothing more than a large tank that both receives water from the condenser as well as supplying water to the condenser.

buffer tank

What two functions does the evaporator of a domestic refrigerator perform? a. filters and cools the air b. absobs and dissipates heat c. humidifies and cools the air d. dehumidifies and cools the air

The temperature of the fresh food compartment of a domstic refirgerator is _____. a. 20 - 35 F b. 50 -60 F c. 30 - 50 F d. 35 - 40 F

The heaters locted near the refrigerator door to keep the cabinet from sweating are called the ______ heaters. a. defrost cycle b. mullion or panel c. condensate d. re -cycle

An accumulator at the outlet of the evaorator is there to ______. a. accumulate moisture in the system to reduce frost formation b. allow the evaporator to operate as full as possible with liquid refirgerant c. provide space for refrigerant vapor to collect d. accumulate foreign particles and other contaminants

The plastic in the freezer compartment is at very low temperature and as a result is quite _____. a. clean b. fragile c. soft d. ductile

The type of condenser that a domestic refirgerator uses can be a ______ condenser. a. static b. induced draft c. hot wall d. all of the above

The condensate from the evaporator coil is disposed of by evaporation using heat from discharge line or _______. a. heated air from the condenser b. air from the evaporator fan c. electric heater in the drian pan d. heat from the compressor fins

The capillary tube metering device on a domstic refrigerator is generally fastened to the _______ for heat exchange. a. liquid line b. compressor discharge line c. condenser coil d. suction line

The adjustment device used for low atmospheric pressure conditions is called the thermostat _______ adjustment control. a. PTC b. current relay c. altitude d. mullion

On a domestic refrigerator equipped with a defrost cycltte that depends on the run time of the compressor, what starts the defrost cycle? a. cooling thermostat b. compressor c. defrost timer d. door switch

One sure fire way to determine if the system is operating with less than full charge of refrigerant is to evaluate the ______. a. cooling thermostat setting b. evaporator superheat c. nitrogen pressure d. defrost timere

The refrigerant charge in a domestic refrigerator amounts usually to only a few a. ounces b. pounds c. grians d. microns

Which of the following represents the vacuum level that should be achieved on a domestic refrigerator before charging? a. low b. deep c. moderate d. very low

T/F THe purpose of door gaskets on a domestic refrigerator is to keep the noise level down when the door is closed

T/F A household refrigerator may have more than one evaporator coil.

T/F The best tool for defrosting an evaporator coil is a knife.

T/F The defrost timer motor operates independently of the compressor motor.

T/F When installing a line tap valve on the high pressure side of the system, it is best to install it on the compressor process tube.

T/F When performing a repair on an aluminum evaportor, the best solution is to use an acetylene torch in conjunction with phos - copper brazing rods.

T/F When a suction line filter drier is added to the refrigerant circuit, the additional amount of refrigerant required is ignored.

The most common type of compressor housing used in a domestic refrigerator is the _____ type.

hermetic

To repair a leak in an aluminum evaporator a special epoxy product may be applied to the hole while the unit is in a slight ______.

vacuum

The operating pressure of the condenser in a domestic refrigerator will increase as the temperature of the room ______.

increase

The typical box temperature for a stand alone freezer is about _______F.

The expansion device commonly found on domestic refrigerators is the ______.

capillary tube

A current magnetic relay is often used to assit in the starting of the compressor, but most new appliances use a ______ device.

PTC

The process of charging from a soild to a vapor is known as ______.

sublimation

Cooling only room air conditioners are marketed in ______ Btu/h capacities. a. 1,000 to 15,000 b. 3,000 to 20,000 c. 4,000 to 24,000 d. 5,000 to 30,000

The evaporator of a window air conditioner should operate _______. a. far below freezing temperature b. far above freezing temperature c. just above freezing temperature d. at 15 F

The condensate off the evaporator coil in a room air coonditioner is generally disposed of by ______. a. draining to the outside soil b. piping to a storm drain c. draining to the slinger system of the fan d. draining to a holding tank

The most common refrigerant used in older room air conditioners is _____. a. R -12 b. R-22 c. R-500 d. R-410a

The evaporator typically operates ____ the dew point temperature of the room air. a. much lower than b. much higher than c. below d. above

The round piece fastened to the outler tips of the condenser fan blade is called the ______. a. blade brace b. dip ring c. air spreader d. slinger ring

A heat pump style room air conditioner has all the major components of a cooling only unit with the addition of a _____. a. 3 way valve b. 4 way valve c. quarter turn valve d. line tap valve

To ensure correct direction of refrigerant flow in heat pump style room air conditioners, ____ are included in the unit. a. filter drivers b. globe valves c. quarter turn valves d. check valves

The window unit must be installed in such a manner that air can circulate across the ____ and not recirculate or high head pressure will result. a. condenser b. evaporator c. compressor d. metering device

The addition of a window air conditioner of ______ size overoad a circuit. a. medium b. any c. small d. large

The most common refrigerant used in newly manufactured room air conditioners is _______. a. R 12 b. R 22 c. R 500 d. R 410a

The term used to reference the assembly of all the components that make up the air conditioning system is ______. a. casement b. sleeve c. chassis d. wrap around

When servicing an R 410a window air condtioner, adjust the airflow across the condenser until the heat pressure reaches _______. a. 360 psig b. 400 psig c. 420 psig d. 460 psig

T/F Cooling only window air conditioners range in size from about 4,000 Btu/h to 24,000 Btu/h.

T/F The compressor for room units is a typical hermetically sealed air conditioning compressor.

T/F Electrical service for a room unit may also involve the thermostat and the power cord.

T/F Combination cooling and heating units may include electric strip heaters or be of the heat pump style.

T/F Heat exchange between the capillary tube and the suction line is typically found on window air conditioners.

T/F If a window air conditioner is installed with an inward pitch, the condensate could leak into the room.

T/F All 230 V power supplies use the same style plug

T/F The thermostat for room units is usually mounted with the control knob in the control center and the remote bulb in the vicinity of the return air.

T/F An extremely dirty air filter can cause the window air conditioner to operate at low suction pressures.

The metering device in a modern room air conditioner is a _______.

capillary tube

In a heat pump style room air conditioner in the heating cycle, the indoor coil acts as the ______.

condenser

In a heat pump room air conditioner in the cooling cycle, the indoor coil acts as the ______.

evaporator

Window installation of room units are for either double hung or ________ windows.

casement

How many air moving motors do cooling only room air conditioners usually have?

one

Central air conditioning systems operate with a design evaporator saturation temperature of about ______ F.

The evaorator of a chiller can be used to absorb heat from _______. a. water b. a solution of water and polyethylene glycol c. the refrigerant d. both a and b

Two basic categories of chillers are the ____. a. compression cycle and absorption b. purge and absorption c. absorption and lithium bromide d. purge and lithium bromide

A benefit of operating a compressor unloaded is _______. a. reduced energy cost b. reduced compression ratios c. increased cooling d. both a and b

A reciprocating compressor with six cylinders, three banks of two cylinders wach, can have its capacity reduced by unloading _____% of full capacity. a. 12.5 b. 25 c. 33 - 1/3 d. 50

Speeds up to _____ rpm are used in centrifugal compressors. a. 15,000 b. 20,000 c. 25,000 d. 30,000

A centrifugal compressor uses _____ for capacity control. a. guide vanes b. block vanes c. guide blocks d. control vanes

Direct expansion evaporators have ______. a. expansion joints between sections of the evaporator b. an established superheat at the outlet of the evaporator c. subcooling at the outlet of the evaporator d. an establshed superheat at the inlet of the evaporator

The compressor used in low pressure chillers are the ______ type. a. reciprocating b. scroll c. screw d. centrifugal

When a chiller using a low pressure refrigerant is operating, the low pressure side of the system ______. a. always shows a positive pressure b. is always in a vacuum c. contains a mixture of oil and air d. rejects oxygen and moisture

A purge unit ______. a. helps to provide subcooling in the condenser b. helps to provide superheat in the suction line c. relieves non condensable gases from the system to the atmosphere d. provides capacity control

T/F To unload a reciprocating compressor, hot gas bypass across the cylinder is the best method.

T/F When referring to evaporators, the term direct expansion and dry type can be used interchangeably.

T/F High pressure chillers use either air or water cooled condensers.

T/F Thermostaitc expansion valves are the only metering devices used in high pressure chillers.

T/F Low pressure chillers use either air or water cooled condensers.

T/F Lithium bromide is ideal for use in absorption system because it is non corrosive.

T/F Electronic starters are much smaller than conventional starters.

A chiller typically cools ____ (what liquid) for the purpose of air conditioning.

water

In centrifugal compressors, capacity control is accomplished by the use of ______ at the impreller inlet.

guide vanes

The pressure difference in a low pressure chiller is produced by a _______ compressor.

centrifugal

The device that automatically helps to remove non condensables from a chiller is called a ______.

purge unit

The pressure difference in an absorption chiller where the source of energy is stem or hot water is produced with the use of a ______ solution.

lithium bromide

The refrigerant in an absorption chiller whose source of energy is steam or hot water is _______.

water

Technician A says that a cooling tower can reduce the temperature of teh water supplied to the condensers to a temperature equal to, but not less than, the wet bulb temperature of the ambient temperature of the ambient air. Technician B says that a cooling tower's approuch temperature is the temperature of the water returning from the water cooled condensers. Which of the following statements is correct? a. Technician A is correct. Technician B is correct b. Technician A is correct Technician B is incorrect c. Technician A is incorrect Technician B is correct d. Technician A is incorrect Technician B is incorrect

If the blower on a cooling tower breaks down on a hot day the ______. a. approach temperature will increase b. water supplied to the condensers will be warmer c. efficiency of the tower will increase d. both a and b

The heat that the cooling tower must reject from the water in the chiller is the cooling load of the conditioned area plus the heat of _______. a. absorption b. compression c. vortexing d. cavitation

Cooling towers are designed to reduce the enetering water temperature to within _______ F of the air's wet bulb temperature. a. 3 b. 7 c. 14 d. 35

When sizing a cooling, the tower is sized to handle the cooling load of the conditioned area plus about ____ % for heat of compression. a. 0 b. 15 c. 25 d. 35

A new chemical free water purification technology is used in cooling towers to ______. a. avoid vortexing b. balance the water flow c. eliminate scale d. all of the above

The term _____ refers to the process of cooling the circulating condenser water by evaporating the tower water. a. cyclic b. adaibatic c. isothermal d. polytropic

Natural draft towers and spray ponds are disigned to produce a difference in water and air temperature of _____F. a. 3 b. 5 c. 7 d. 10

Two methods used to aid the evaporation rate of water in a forced or induced draft tower are ______. a. vortexing and cavitation b. spray pond and prevailing wind c. float type valve and by pass valve d. splash and wetted surface

A blowdown system for a cooling tower a. reduces the concentration of sediment in the sump b. provides extra draft for higher evaporation rate c. promotes vortexing d. provides a means for balancing the water flow

The purpose of the cooling tower bypass valve is to ______. a. route debris away from the tower sump b. prevent cavitation at the pump c. provide makeup water to the tower sump d. help maintain the correct water temperture to the condenser

Two types of shaft seals used for centrifugal pumps are ______. a. stuffing box and mechanical types b. stuffing box and splash type c. ceramic and splash types d. ceramic and bellows types

T/F Spray ponds on rooftops have made a comeback in the last few years because they cool the roof and reduce the solar load on the structure.

T/F A well designed and installed cooling tower requires only a minimum of maintenance.

T/F Distilled water is added to the cooling tower to make up for water lost during blowdown.

T/F The condenser water pump is the device that moves the water through the condenser and cooling tower circuit.

T/F If vortexing occurs, it is an indication that there is not enough air in the tower.

The difference between the entering air wet bulb temperature and the temperature of the water leaving the tower is called the ______.

approch

Natural draft cooling towers usally has an approach temperature of about _____ F because of relying only on the winds.

A spray pond would be an example of a _____ draft cooling application.

natural

Larger cooling towers generally use _______ type fans.

perpeller

The two air flow patterns for cooling towers are _______ and counterflow.

downflow

_______ allow the motor to soft start and to coast down without abruptly shutting the motor off.

VFD

Condenser water pumps are normally ______ pumps.

centrifugal

The first step in starting a chilled water system is to ___. a. activate the compressor unloading system b. establish the chilled water flow c. activate the condenser heat removal system d. start the compressor operation sequence

There should be a _____ test point at the inlet and outlet of any water heat exchanger, chiller or condenser. a. temperature b. pressure c. vapor d. moisture

When a water cooled chiller is operating normally, it can usually be left unattended, except for which component? a. the condenser b. the evaporator c. the metering device d. the cooling tower

Recipocating chillers have crankcase heaters to ______. a. preheat the chiller water for better efficiency b. prevent refrigerant migration to the crankcase c. preheat the compressor bearing for longer wear d. minimize condenser subcooling

Chillers manufactured in the last few years all have _____ controls. a. electronic b. hydraulic c. pneumatic d. pressure based

Water cooled chillers must have water treatment to _____. a. increase the ph content of the water in the sump b. decrease the ph content of the water in the sump c. prevent minerals and algae from forming in the water circuit d. help preheat the water in the condenser water circuit

Centrifugal chillers range in size from ____ tons for a single chiller. a. 10 to 50 b. 10 to 80 c. 50 to 500 d. 100 to 10,000

A typical chiller water system is desigend to operate with a leaving water temperature of ____ F. a. 35 b. 40 c. 45 d. 50

What may happen if a lithium bromide absorption system is started with the cooling water too cold? a. high head pressure in the system b. low head pressure in the absorber c. removal of system load, compressor cylinders will unload d. crystallization occurs

T/F The operation of chiller involves starting, running, and stopping the sytstem's components in an orderly manner.

T/F After chemically cleaning a condenser, it jis extermely important to make sure that the chemcials are neutralized or the tubes may be damaged.

T/F If an absorption chiller makes an ice crackling sound it is an indication that no condenser water is flowing.

T/F If the purge unit on a chiller is operating very frequently, the system may have a leak.

T/F Low pressure chillers operatre in a vacuum and will stay in a vacuum if the equipment room is not warm enough to keep the refrigerant warm.

The technician should also be aware of the _____ through the contacts that must be satisfied before startup.

interlock

The safety switch in the chiller water line that is activated by water flow is called a _____.

flow switch

Ball valves for refrigerant piping are used for larger appliactions and come in size up to about _____.

2 7/8

The scroll chiller compressor needs crankcase heat and it must be energized for the length of time the manufacturer requires, usually _______ hours.

The ______ creates must less pressure drop through the valve than the globe valve and is a much better application where excess pressure drop is a consern.

gate valve

The ______ is used in water circuit and is a quick shutoff vavle? as it only needs to be turned one quarter turn from on to off, like a ball valve.

butterfly valve.

To remove particles that may be in suspension and circulating in a water circuit an ______ is used.

strainer

If the compressor motor megohm value begins to decrease, it is a sign that ______ or some other foreign matter may be getting into the system.

moisture

There are three lines of defense against refrigerant leaks in a servie valve ; the back seat , the packing gland and the ______.

protective cap

If an absorption unit is started with very cold water in the cooling tower, the lithium bromide in the unit may _______.

crystallize