setup and install

What is the friction rate of 8" metal duct that is carrying 200 CFM? A. ≈.075 B. ≈.14 C. ≈.095 D. ≈.17

A

Flexible duct comes in ___ feet lengths. A. 15 B. 25 C. 50 D. 100

B

What are the general CFM requirements per ton for cooling? A. 300 B. 350 C. 400 D. 450

C

The industry standard for the maximum recommended air velocity for a register in a home is ____FPM. A. 600 B. 650 C. 700 D. 750

D

What is the volume of one pound of perfectly dry air? A. .0133 FT3/LB B. .1333 FT3/LB C. 1.333 FT3/LB D. 13.33 FT3/LB

D

A ________ is used to measure the pressure inside a duct. A. Micromanometer B. Specialized compound gauge C. MAnifold gauge set D. String on a stick

A

According to the Hart and Cooley submittal drawing, flexible duct is made of what components? A. Core, insulation and vapor barrier B. Insulation and vapor barrier C. Inner sleeve and vapor barrier D. All of the above

A

According to your instructor, the best instrument to measure airflow at grilles is the: A. A flowhood. B. An anemometer and a tape measure. C. Your hand, slightly dampened. D. A stick and string.

A

How is the end cap affixed to the duct board plenum? A. Cut to fit shiplapped end of the plenum, the flaps secured with adhesive, staples and tape. B. Cut to fit the outside dimension of the plenum, flaps folded down and then secured with staples and tape. C. Cut to fit the inside of the plenum, with stripes of tape running along all 4 sides to hold the cap in place. D. It is held in place by cutting the end cap 3/8" larger than the opening and suffering in the plenum.

A

In the most common cooling system, the common cooling application is to what? A. Cool and dehumidify B. Cool and humidify C. Cool D. Increase moisture content and increase dew point.

A

It is generally agreed that at least ____% air change per hour for the entire structure is desirable. A. 25 B. 30 C. 15 D. 20

A

The simple ways to check for airflow is to see if you can feel the velocity at about _____ to _____ feet from each register. A. 2 to 3 B. 3 to 4 C. 1 to 2 D. 5 to 6

A

Three of the indoor pollution sources are: A. Carpets, cooking odors and paint vapor. B. Radon, pets and car exhaust C. New furniture, vapor from aersol cans and VOC's from roof shingle. D. All of the above.

A

Typically, the body is at rest and in surroundings of ____ºF and _____% RH with a slight air movement, the body is close to being comfortable. A. 75 & 50 respectively B. 65 & 45 respectively C. 75 & 45 respectively D. 65 & 50 respectively

A

Whar are two effects of undersized ducts? A. Causes excessive velocity & increased duct noise. B. Causes increased duct noise & lower static pressure. C. Causes the air flow pattern to be altered & a decrease in total pressure through the duct. D. Causes an increase in duct noise & a decrease in velocity.

A

What are four general types of air cleaners? A. Mechanical filters, electronic air cleaners, ion generators and UV light. B. Pleated, woven, spun and adhesive. C. Electronic, pleated, spun-glass and washable. D. Sock or pocket filters, UV-C light, spun-glass and pleated.

A

What effect does a reduction of return air flow have on the temperature of the supply air during a call for cool? A. The supply temperature will decrease. B. The supply temperature will increase. C. The amount of return air has no effect on supply temperature. D. All of the above are incorrect.

A

What effect does blocked evaporator air flow have on the system superheat? A. The superheat will decrease. B. The superheat will increase. C. The superheat will not be affected. D. Air flow not effect on superheat, so both C & D are correct.

A

What is a diffuser? A. A device which directs air in a certain direction using louvers. B. A screening device used to starighten out airflow in supply boxes. C. A device by which supply air is mixed with room air before being expelled into the room. D. A device by which the return air is slowly diffused, allowing for better return air flow.

A

What is a streamlined takeoff? A. The takeoff that has a larger throat area than the runout duct. B. The takeoff that has a smaller throat area than the runout duct. C. The takeoff that you experience when there is no line at airport security. D. The takeoff that has an area equal to that of the runout duct.

A

What is infiltration? A. Random air that leaks into a structure. B. Air that is exhausted from the bathroom or kitchen. C. Air that is passed over an heat exchanger before being exhausted to the outside. D. Both B & C

A

What is one of the two statements thatr can be used as guildlines for comfort in summer? A. When the humidity is high, air movement helps. B. Lower temperatures can be offset with lower humidity. C. The lower the humidity is, the higher the temperature must be. D. All of the above.

A

What is static pressure? A. The pressure of the air passing against the side the walls of the duct. B. The pressure of the air passing against the center tube in the pitot tube. C. Both A & B D. None of the above

A

What is the installation code for forming a bend in flexible duct? A. Bends shall not be less than 1 duct diameter centerline radius. B. Bends shall not be more than 1 duct diameter centerline radius. C. Bends shall be made immediately after the collar or take off. D. Bends shall use the doouble S curve when coming off a plenum.

A

What is the maximum ACCA recommended velocity for residential rigid return ducts? A. 700 FPM B. 800 FPM C. 900 FPM D. 1,000 FPM

A

What is total pressure? A. The sum of velocity pressure plus static pressure. B. The pressure of the air pressing against the center of the pitot tube. C. Both A & B D. None of the above

A

What three of the four components which make up the forced air system? A. Blower, supply air system, grilles & registers B. Blower, heat exchanger, filter C. Blower, indoor coil, filter rack D. Blower, heat exchanger, plenum

A

When a damper is closed, it will restrict the air to only about ___%. A. 15 B. 20 C. 25 D. 30

A

When constructing a flexible duct system, bends shall be less than ____ duct diameter centerline radius. A. 1 B. 2 C. 3 D. 4

A

Where would a one way grille best be utilized? A. In a long narrow hallway. B. In a 20'x40' room that has 8' ceilings. C. In any room, as long aqs the grille is placed just inside the doorway. D. One way grilles should never be used.

A

Which tools are used to fabricate a metal plenum? (Lab3) A. Hammer, scribe, snips and lockformer. B. Hammer, shiplap tool, scribe and foil tape C. Scribe, permanent marker, tin snips and hammer D. None of the above.

A

Which type of grille caused the air to flow parallel to the ceiling? (Lab 10) A. One way curved blade grille. B. One way stamped face grille. C. Two way wall diffuser. D. None of the above.

A

Why is it important to size the duct to the load? A. To delivered the required CFM to the room. B. To prevent temperature swings throughout the structure. C. To ensure the load(s) are bathed with conditioned air. D. All of the above.

A

Air consists of ___% nitrogen, _____% oxygen and ____% other gases. A. 21,78 & 1 respectively B. 78,21 & 1 respectively C. 74,25 & 1 respectively D. None of the above.

B

All air measurements for residential systems should be performed at: A. On low speed fan B. On high speed fan C. On medium speed fan D. It does not matter.

B

Any change in heat content or moisture will cause: A. Nothing to happen. B. A change in the wet bulb reading and, therefore, aq change in the total heat content. C. A reduction of the heating load. D. The cooling load to triple for every 2% increase in heat content over normal conditions.

B

How will blocked evaporator air flow affect the compressor during a call for cool? A. The current draw will increase. B. The current draw will decrease. C. The cold resistance of the common to run winding will increase. D. The current draw will not change.

B

The industry standard for CFM per ton of cooling is: A. 350 CFM per ton. B. 400 CFM per ton. C. 450 CFM per ton. D. None of the above.

B

What are two effects of oversized ducts? A. Costs more & results in higher static pressure. B. Cost more & results in the slowing of air flow. C. Cost more & results in attenuated blower noise. D. Cost more & results in noise being generated by grilles and diffusers.

B

What can be used to improve air flow in square throated elbows? A. Install a damper in the entrance of the square throated elbow. B. Install internal guide vanes in the square throated elbow. C. Install a diffuser at the entrance of the square throated elbow. D. All of the above

B

What does MERV mean? A. Minimum efficiency rated value B. Minimum efficiency reporting value C. Maximum efficiency rated value D. Maximum efficiency reporting value

B

What is a vibration eliminator? A. A flat lead wight that is placed inside a duct to dampen any and all vibration. B. A canvas or rubber connector that is used to join two sections of sheet metal ducts. C. The weight that is clipped top the fan blade so that the fan is balanced. D. The spare tire that is placed on top of the condensing unit to absorb vibrations.

B

What is one of the effects of ducts that are undersized? A. Decreased static pressure. B. Excessive duct velocity. C. Slowing of the air velocity ddue to decreased friction rate. D. Decreased throw.

B

What is relative humidity? A. The actual amount of water vapor that is contained in an air sample. B. The relationship between the weight of water vapor ina pound of air compared with the weight of water vapor that a pound of air could hold if it were 100% saturated. C. The relationship between the volume of 1 pound of water and one pound of perfectly dry air. D. All of the above.

B

What is the CFM delivered from a 8" duct if the velocity is 700 FPM? A. ≈185 CFM B. ≈240 CFM C. ≈1675 CFM D. ≈2025 CFM

B

What is the area of a 10" duct? A. ≈120 Sq in B. ≈80 Sq in C. ≈65 Sq in D. ≈55 Sq in

B

What is the difference between a register and a grille? A. There is no difference between a register and a grille. B. The register has a damper and the grille does not. C. The grille has a damper and the register does not. D. None of the above

B

What is the formula to determine the heating equipment load due to ventilation? A. Q=1.08 x HspxTD B. Q=1.08xCFMxTD C. Q=4.5xCFMxTD D. Q=1.8xCFMxTD

B

What is the friction rate of a 7" duct that has a velocity of 640 FPM? A. ≈.15 B. ≈.26 C. ≈.20 D. ≈.18

B

What is the recommended distance between hanger supports on a flexible duct installation? A. Not greater tha 4 feet. B. Not greater than 5 feet. C. Not greater than 6 feet. D. Not greater than 4 times the duct diameter

B

What is the velocity of a 10" duct ≈485 CFM? A. ≈800 FPM B. ≈900 FPM C. ≈.15 FPM D. ≈700 FPM

B

What is the weight of perfectly dry air? A. .0075 LB/FT3 at standard atmospheric pressure. B. .075 LB/FT3 at standard atmospheric pressure. C. .75 LB/FT3 at standard atmospheric pressure. D. None of the above.

B

What size round duct is required to provide 300 CFM with a velocity of 600 FPM? A. 9" B. 10" C. 11" D. None of the above.

B

Where would a circular diffuser grille be best located in a room? A. Between rooms, so that one duct can cool or heat two rooms. B. In the center of the room. C. In the room, 5 feet from the exterior wall. D. In the room, 5 feet from the interior wall.

B

Which filter is more efficient, a MERV 6 or a MERV 14 filter? A. MERV 6 B. MERV 14 C. Both have the same efficiency rating D. Both A & B

B

Which side of the duct board is used as an air tight vapor barrier (outside)? A. The side coated with the micro. B. The side with the foil scrim craft surface. C. It does not matter which side faces out. D. Both A & C

B

Which tools are used to fabricate a metal plenum? (Lab3) A. Hammer, scribe, snips and lockformer. B. Hammer, shiplap tool, scribe and foil tape C. Scribe, permanent marker, tin snips and hammer D. None of the above.

B

What is the fresh air entering the building envelope through cracks and openings around doors and windows known as? A. Ventilation air B. Infiltration air C. Dilution air D. Calculated air

B. Infiltration air

One of the ways a typical homeowner may take to prevent outside air from entering the structure? A. Installing ceiling fans. B. Installing a light colored roof. C. Caulking around windows and doors. D. All of the above.

C

Plenums and ducts should be sealed so that they are: A. Dust proof B. Sound proof C. Leak proof D. Water tight

C

The best method of sealing a duct system is using: A. Great stuff Expanding FoamTM B. Black or gray duct tape C. Mastic D. All of the above

C

The real area of a return-air grille is approximately ____ of the grille opening. A. 50% B. 60% C. 70% D. 80%

C

What are drive connections? A. The connections that are used in duct board that uses flaps, staples and tape. B. The cross streets that technicians use when transversing across a town or city. C. The connections that to hold sheet metal duct together. D. The connections that are used when joining duct board ducts to sheet metal ducts.

C

What are three of the four common duct configurations? A. Perimeter loop system, radial, common return. B. Radial system, plenum, reducing plenum. C. Extended plenum, reducing plenum, radial system D. Supply, return, air mixing(ERV)

C

What is a damper? A. A device on a grille to help direct the direction of the air flow. B. A device used to straighten out air flow in a duct. C. A device that is used to balance air flow in a branch or shut off air flow to a zone. D. All of the above

C

What is enthalpy? A. The heat content of the air that takes into account only the sensible heat. B. Both A & C are correct C. The measure of heat content of the air. D. None of the above.

C

What is one of the effects of ducts that are oversized? A. Duct/grille/register noise B. Increased static pressure. C. Decreased air velocity D. Increased throw

C

What is one of three statements that can be used as guildlines for comfort in winter? A. Lower temperature can be offset with lower humidity. B. Air movements is less noticable. C. The lower the humidity is, the higher the tempearture must be. D. All of the above

C

What is the CFM of a 8" duct that has a velocity of 640 FPM? A. ≈165 CFM B. ≈180 CFM C. ≈220 CFM D. ≈300 CFM

C

What is the code for hanger or saddle material used in flexible dusct installations? A. The material shall not be less than 1" wide and is permitted to restrict the internal diameter of the duct. B. The material shall not be less than 1.5" wide and is permitted to restrict the internal diameter of the duct. C. The material shall not be less than 1.5" wide. D. The material shall not be less than 1" wide.

C

What is the intended purpose of a triangle box? A. All of the following are correct. B. To be used as a pillow when a technician is working on horizontal units. C. To run two smaller ducts runs off of one larger duct. D. To run one large duct run off of two smaller ducts.

C

What is the maximum ACCA recommended velocity for residential flexible supply ducts? A. 700 FPM B. 800 FPM C. 900 FPM D. None of the above, ACCA does not have a recommended maximum velocity.

C

What is the maximum permissible sag between supports on a flexible duct installation? A. 1.5" per foot of support spacing B. 1" per foot of support spacing. C. 1/2" per foot of support spacing D. 1/4" per foot of support spacing

C

What is ventilation? A. Introducing air from the kitchen and bathroom into the return air path in order to filter the air. B. A means of returning the air from the plenum, back to the return air in order to lower the relative humidity. C. Introducing outside air into the air conditioning system in order to keep the air from becoiming oxygen-starved and stagnant. D. None of the above

C

What would be the effect of starting a system, when the space temperature (load) is higher than normal for standard efficiency equipment? A. The discharge pressure will be higher than normal and the suction pressure will decrease. B. The discharge pressure will be lower than normal. C. The suction pressure will be lower than normal. D. None of the above.

C

When constructing a flexible duct system, where should balancing dampers be placed? A. Dampers should not be used on flexible duct systems. B. Dampers should be placed just before the grille/register/diffuser. C. At the take-off or collar on each duct run. D. Dampers should be placed at mid-point on each duct run.

C

Where are UV lights typically positioned? A. Either close to the veaporator coil or in the plenum. B. Either close to the filter or in the plenum. C. Either close to the air filter or the evaporator coil. D. Both A & B

C

Which duct would carry or attenuate fan or blower sound? A. Flexible duct B. Metal duct with duct liner C. Metal duct D. Duct board

C

Which tools are used to fabricate a suct board plenum? (Lab1) A. V-groove tool, duct knife, ship lap tool and inward cinch stapler B. Break, tin snips or aviation snips, hammer. C. V-groove tool, duct knife, ship lap tool and outward cinch stapler. D. Packing tape, pocket knife, hammer and ruler.

C

Which type of duct material has the highest friction rate? A. Duct liner B. Duct board C. Flexible duct D. Galvinized metal duct

C

According to the textbook, what are two considerations when selecting a filter? A. Type of filter and cost effectiveness. B. Filteration rating and size. C. Size and cost. D. Capacity and amount of pressure drop

D

How many CFM should a 2.5 ton air conditioning system deliver? A. 400 CFM B. 600 CFM C. 800 CFM D. 1,000 CFM

D

How will blocked evaporator air flow affect system pressures? A. The low side pressure will increase and the high side pressure will decrease. B. The low side pressure will decrease and the high side pressure will increase. C. The low side pressure will not change and the high side pressure will increase. D. Both the high side and low side pressures will decrease.

D

If a filter rack was designed for a typical media filter and a high-density filter is used, it is likely that the airflow is: A. Increased due to the Coanda effect. B. Not changed, all filters offer the same resistance to air flow. C. I do not know. D. Reduced to the point of low flow.

D

What are 2 of the 3 considerations homeowners should consider before having the air ducts cleaned? A. It has been 2 years since the last duct cleaning & there is mold present in the ducts. B. The evaporator coil keeps freezing & air filter has not been changed in 3 months. C. The ducts were newly installed & if there is dust and dirt in the duct. D. None of the above.

D

What are two of the characteristics that the 4 components of a forced air system are correctly chosen? A. Low electric bill & the spouse is happy. B. No temperatures swings throughout the structure & you can hear the air coming out of the ducts. C. No air movements felt in the conditioned space & the static pressure is very low. D. No temperature swings throughout the structure & no duct or fan noise.

D

What are two of the most popular types of fans? A. Centrifugal & squirrel cage B. Propeller & Axial C. Oscillating & Direct D. Centrifugal & propeller

D

What is special about the staples used in securing the flaps when working with duct board? A. The staples were inward cinch. B. The staples are common ordinary desk staples. C. Both B & C D. The staples are outward cinch

D

What is the definition of "throw"? A. The distance the air travels from a grille before slowing to 400 FPM. B. The distance the air travels from a grille before slowing to 350 FPM. C. The distance the air travels fom a grille before slowing to 250 FPM. D. The distance the air travels from a grille before slowing to 150 FPM.

D

What is the formula to determine the cooling equipment load due to ventilation? A. None of the following. B. Q=4.5xCFMxHsp C. Q=1.08xCFMxTD D. Q=4.5xCFMx Total heat difference

D

What is the installation code for collars and sleeves? A. There is no code for collars and sleeves. B. Collars shall be a minimum of 1 duct diameter and sleeves a minimum of 2 duct diameters. C. Collars shall be a minimum of 3" and sleeves a minum of 6". D. Collars shall be a minimum of 2" and sleeves a minimum of 4"

D

What is the velocity coming out of a 6" duct with a CFM of 290? A. ≈75 FPM B. ≈80 FPM C. ≈1375 FPM D. ≈1500 FPM

D

What is wet bulb temperature? A. Taken with a wet-bulb thermometer. B. It reflects the total heat content of air. C. Takes into account the moisture content of the air. D. All of the above.

D

When is a vibration eliminator recommended? A. Only when the blower is quiet. B. Only in horizontal applications. C. Only when using duct board systems. D. In all installations.

D

Which type of duct material has the lower friction rate? A. Duct liner B. Duct board C. Flexible duct D. Galvinized metal duct

D

With a 10" duct ≈485 CFM that has the velocity of≈900 FPM, does the duct meet or exceed the ACCA recommended minimum duct velocity? A. Meets ACCA recommendations. B. Exceeds ACCA recommendations. C. Does not meet ACCA recommendations. D. None of the above.

D

n the most common heating system, the common heating application is to what? A. Heat B. Dehumidify C. Humidify D. Both A & C

D

According to your textbook, the definition of comfort is defined as: A. A balance between air movement and air temperature. B. When there is equilibrium between the heating and cooling loads. C. An equal sensation of being hot and cold. D. A delicate balance of pleasant feeling in the body. .

D.

Comfort involves what four things? A. Air cleanliness, duct noise, drafts and humidity. B. Air cleanliness, air movement, humidity and air velocity. C. Air cleanliness, humidity, air velocity and duct noise or lack thereof. D. Air cleanliness, temperature, humidity and air movement

D.

The changing from a stamped face grille to a curved blade grille, the air flow pattern and throw will not change. True False

FALSE