UNIT 7

Question 1

The joining of two pieces of copper tubing of the same diameter by expanding or stretching the end of one piece to fit over the other, so that they can be soldered or brazed

Answer 1

Swaging

Question 2

Produces flame temperatures in the range of 3600°F slightly higher than butane

Answer 2

Propane

Question 3

Consist of a liquid line and insulated suction line. That may be pre-charged with refrigerant, and sealed at both ends.

Answer 3

Line set

Question 4

Plastic pipe used for hot or cold water supplies that can withstand temperatures up to 180°F at 100 psig. Can be joined by glue or threaded joint.

Answer 4

CPVC

Question 5

Joining two pieces of copper tubing, utilizing filler material that melt at temperatures under 842°F usually in the 361°F to 500°F range

Answer 5

Soldering

Question 6

Prevent oxidation from forming on the surface of pipes being joined, and in the filler materials themselves. Also helps facilitate the flow of filler material into the joint.

Answer 6

Flux

Question 7

A mixture of fuels that produce flame temperatures of about 3730°F

Answer 7

MAPP gas

Question 8

Used to remove burrs after cutting tubing or steel pipe

Answer 8

Reamer

Question 9

Threads designed to form a metal to metal seal with or without sealant by using thread deformation

Answer 9

National pipe taper

Question 10

Measure from the outer diameter instead of the inner diameter

Answer 10

ACR tubing

Question 11

The oxygen regulator pressure is set to 10 psig when the valve on the torch head is cracked open. What is the acetylene pressure regulator set to when the valve on the torch head is cracked open?

Answer 11

5 psig

Question 12

True or false
Bending springs can be either inside or outside of tubing

Answer 12

True

Question 13

True or false
45% silver is considered soft solder

Answer 13

False

Question 14

True or false
A carbonizing flame is used for most brazing operations

Answer 14

False

Question 15

True or false
Never use a cigarette lighter or match to light a torch

Answer 15

True

Question 16

Flux can overheat, and become saturated with oxides

Answer 16

True

Question 17

True or false
The proper solder to use for a copper to steel joint is 45% silver

Answer 17

True

Question 18

True or false
Plastic pipe does not need to be reamed after cutting

Answer 18

False

Question 19

True or false
Do not apply pipe dope closer than two threads from the end of the pipe

Answer 19

True

Question 20

True or false
Teflon tape should/can be used on compression fittings for a leak free seal

Answer 20

False

Question 21

True or false
PE pipe is used for water, gas and irrigation systems

Answer 21

True

Question 22

True or false
Compression fittings are not intended for refrigerant, piping circuits

Answer 22

True

Question 23

PE pipe is attached to fittings using hose clamps. How are the hose clamp positioned

Answer 23

Screws of the clamp on opposite sides of the pipe

Question 24

Steel pipe should have_________ perfect threads and_______ imperfect threads

Answer 24

7 perfect and 2/3 imperfect threads

Question 25

When soldering flux should be applied to…….

Answer 25

Male part of the joint only

Question 26

Pipe threads when used on pipe that will contain liquid or vapor under pressure……..

Answer 26

All of the above

Question 27

A tube that is over flared will cause what to happen when the flare nut is tightened?

Answer 27

It will cause a leak

Question 28

When soldering without using a nitrogen purge, the oxide formed within the tubing, will eventually travel throughout the system and collect where?

Answer 28

Metering device, filter dryer compressor oil

Question 29

What is the purpose of removing any excess flux after soldering?

Answer 29

To prevent acid buildup on tubing/piping

Question 30

What can be used to clean tubing that will be used on a hermetic compressor?

Answer 30

All of the above

Question 31

When adjusting the flame for a propane/MAPP gas torch, where should the flame be in relation to the torch tip?

Answer 31

Outside of the torch head

Question 32

You are changing out a compressor and need to solder the suction and discharge lines onto the new compressor. The solder on the older compressor tubing is gold in color. What type of solder was used for the joint?

Answer 32

45% silver solder or higher

Question 33

Is flux required to solder the lines onto the new compressor in number 32

Answer 33

Yes

Question 34

Moisture+ acid+ oil=

Answer 34

Sludge

Question 35

Do azeotrope refrigerants have a temperature glide or do they behave like a single compound refrigerant?

Answer 35

No temperature glide and acts like single compound refrigerants.

Question 36

How many BTUs in 8 kW of electrical power?

Answer 36

3413 BTUs= 1kW—-3413BTUs x 8kW= 27,304 BTUs

Question 37

What components make up HFC refrigerants?

Answer 37

Hydrogen, Fluorine, Carbon

Question 38

Lines of constant quality on an enthalpy diagram give you the percentage of________as you go from left to right on the diagram.

Answer 38

Vapor

Question 39

Specific volume is measured in_____________

Answer 39

Cubic feet/lb

Question 40

The density of aluminum is 171 lb/ft3. What is its specific volume?

Answer 40

1/171lb/ft3= 0.00584795 ft3/lb