Unit 38 Installation HVAC

Question 1

One drawback of using custom made,
pre-measured duct sections is that ____.

a. if the measuring was not done correctly, the job may not go together
b. the sharp edges provide possible safety issues
c. altering a duct section at the job site is extremely cost-ineffective
d. all of the above

Answer 1

Answer : D all of the above

Question 2

The reason many installations utilize a straight
main trunk line with flexible duct runs to the
individual register boots is to ____.

a. eliminate the expense of custom-made duct sections
b. reduce excessive noise
c. speed up the installation process
d. all of the above

Answer 2

Answer : D all of the above

Question 3

What two fasteners are used with fiberglass
duct?

a. “S” fasteners (clips) and drive clips (cleats)
b. staples and tape
c. self-tapping screws and draw bands
d. tabs and adhesives

Answer 3

Answer : B staples and tape

Question 4

What two fasteners are used with sheet metal
square and rectangular duct?

a. “S” fasteners (clips) and drive clips (cleats)
b. staples and tape
c. self-tapping screws and draw bands
d. tabs and adhesives

Answer 4

Answer : A. “S” fasteners (clips) and drive clips (cleats)

Question 5

What fastener is commonly used with round flexible duct?

a. “S” fasteners (clips) and drive clips (cleats)
b. staples and tape
c. self-tapping screws and draw bands
d. tabs and adhesives

Answer 5

Answer : C. self-tapping screws and draw bands

Question 6

A good way to fasten insulation to the inside
of sheet metal duct is to use ____.

A. staples and tape
B. coils
C. tabs and glue
D. fasteners and drive clips

Answer 6

C. :Tabs or glue

Question 7

A trap in the condensate line prevents ____.

a. air and foreign material from being drawn up into the drain line
b. additional cooling load from warm air drawn up into the air handler
c. insect invasion of the system
d. all of the above

Answer 7

Answer : D - all the above

Question 8

An auxiliary drain pan under an air handler is
required when the air handler is installed ____.

a. in an attic
b. in a drop ceiling
c. above a traffic area
d. all of the above

Answer 8

Answer : D all the above

Question 9

A boot in a duct system is used ____.

A. at the plenum

b. between the trunk duct and the branch duct
c. between the branch duct and the register
d. to eliminate vibration between the unit and the duct

Answer 9

Answer : C between the branch duct and the register

Question 10

After refrigerant lines have been installed,
they should be evacuated to a pressure of ____.

a. 28” vacuum
b. 28” vacuum
c. 5,000 microns
d. 500 microns

Answer 10

Answer : D 500 microns

Question 11

True/False:The purpose of a canvas connecter in a duct system is to reduce the transmission of noise and vibration.

Answer 11

Answer: True

Question 12

True/False :When installing a split air-conditioning system
with a remote condensing unit, the liquid line, suction line, and low voltage wire can be bundled together and run as a single piece from the condensing unit to the air handler.

Answer 12

Answer :True

Question 13

True/False :Once the power has been

connected to the condensing unit, it is a good idea to start the compressor immediately to make certain it runs.

Answer 13

Answer: Flase

Question 14

True/False : When hanging a horizontal air

handler, it should be pitched toward the drain port for proper condensate removal.

Answer 14

Answer : False

Question 15

True/False : Lining a piece of duct is

accomplished by using tabs and washers and/or glue.

Answer 15

Answer :True

Question 16

True/False : The sun shining on the outdoor

section of the air-conditioning system has a direct affect on the operation of the unit.

Answer 16

Answer :False

Question 17

True/False : A halide torch will only detect

products containing halogen compounds.

Answer 17

Answer :False

Question 18

True/False : A halide leak detector will find a

leak of less than 0.5 oz. per year.

Answer 18

Answer :False

Question 19

Before a system is evacuated, all piping

should be __________________

Answer 19

Answer : Leak Checked

Question 20

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

Answer 20

Answer : Air Handler

Question 21

The typical gauge wire that is used in low

voltage control circuits is __________ gauge.

Answer 21

Answer : 18 Gauge

Question 22

A fitting used to change the size of a square

or rectangular duct is called a _______.

Answer 22

Answer : Transition

Question 23

A round to rectangular fitting is called a(n)

_______.

Answer 23

Answer :Square to Round Transition

Question 24

Even though the cooling wire (usually the “Y”
wire) runs from the thermostat to the air handler, it actually just continues on to the condensing unit. Why isn’t the cooling wire run directly from the thermostat to the condensing unit?

Answer 24

Short Answer :The air handler acts as a junction for the power..everything must
go thru the air handler to pick up the 24 volts from the transformer. Too much wire.

Question 25

A split central cooling system is installed with
the control transformer located in the attic hung air handler and the condensing unit located outside. How many low voltage conductors need to be run to the condensing unit?

Answer 25

Short Answer :Two

Question 26

What materials can be used successfully in

an air-conditioning duct system?

Answer 26

Answer :Flex Duct, Duct Board,

Galvanized Metal

Question 27

If a duct system has large air leaks at the

connections, what can be used to seal them up?

Answer 27

Answer :Mastick & tape

caulk.

Question 28

How much does sunshine affect the operation

of a condensing unit?

Answer 28

Answer :None

Question 29

For what is compressor crankcase heat used?

Answer 29

Answer : To keep refrigerant from migrating to the oil,during
the off cycle or during long periods of off time

Question 30

What is the purpose of insulation on the

suction line?

Answer 30

Answer :To reduce condensation

Question 31

What should be done if the voltage to the unit

is too low?

Answer 31

Answer : Call an Electrical Contractor