REF UNIT 7 Flashcards
(7.2) What is steel-wrought pipe used for?
gas lines and steam heating
(7.2) How is copper piping categorized?
K, L, M, DWV [K being heavy duty, DWV is used for drainage and waste(not typically used in our industry)].
(7.2) What is copper tubing used for refrigeration and air conditioning called?
ACR tubing
(7.2) how is ACR sized?
by outside diameter
(7.2) How is plumbing and heating tubing sized?
by inside diameter
(7.2) Define annealing
the process of heating and slowly cooling a metal in order to strengthen it (specifically copper tubing).
(7.4) What do line sets come with?
liquid line and vapor line
(7.6) What are the 2 tools used in bending tubing?
tube bending springs and lever-type tube benders
(7.7) What is the soldering temperature range?
361F to 500F
(7.7) What is the brazing temperature range?
1205F to 1550F
(7.7) What are the two common filler metals used in soldering?
- 50/50 (50% tin, 50% lead), used for moderate pressures and temperatures.
- 95/5 (95% in, 5% antimony), used for high pressure water lines.
(7.7) Why must brazing be done in some applications?
because of the filler material
(7.7) What 2 filler metals can be used in brazing?
a silver alloy or a copper-phosphorous alloy
(7.8) What are the 5 common torch types found in the industry?
propane, butane, oxyacetylene, MAPP gas, and air-acetylene.
(7.8) What torch produces the hottest flame?
Oxyacetylene torch
(7.9) What does flux do in brazing and soldering?
prevents oxidization and facilitates filler material flow.
(7.9) Where do you apply flux?
only on the male part of the connection
(7.9) Why should a phosphorous filler material never be used when brazing with steel?
because phosphorous and steel produce phosphides, which are easily cracked.
(7.9) How do you displace oxygen in pipe that is being brazed?
pressurize system with 1 to 2 psi(g) of nitrogen.
(7.16) How is steel pipe specified?
ID for pipes less than 12 inches diameter, OD for pipes more than 12 inches diameter.
(7.16) What are the only type of threads used on steel pipe in the HVAC industry?
tapered threads
(7.16) How is pipe threading specified?
thread diameter, number of threads per inch, National pipe taper (1/2-14 NPT).
(7.17) What does pipe dope do?
helps seal pipes.
(7.18) What is ABS piping for?
drainage, waste, venting
(7.18) What is polyethylene (PE) piping for?
cold water, gas, irrigation (only low pressure).
(7.18) What is PVC piping for?
high pressure, low temperature applications (like gas, waste).
(7.18) What is CPVC piping for?
like PVC but can be used with high temperatures.
