hard ones Flashcards
(3.8) In what systems are scroll compressors usually found?
in new residential and light commercial air conditioning applications.
(6.2) What is the name of a rivet and pin together?
a mandrel
(6.3) How are wood crews specified?
by shank number (0 to 24) and length (in inches)
(6.3) What are sheet metal screws also known as?
tapping screws
(7.2) How is copper piping categorized?
K, L, M , DWV (K being heavy duty, DWV is used for drainage and waste).
(7.2) How is ACR sized
by OD
(7.2) Define annealing
the process of heating and slowly cooling a metal in order to strengthen it.
(7.7) What is the soldering temperature range?
361F to 500F
(7.7) What is the brazing temperature range?
1205F to 1550F
(7.16) What are the only type of threads used on steel pipe in the industry?
tapered threads
(7.18) What is ABS piping for?
drainage, waste, ventilation.
(7.18) What is PE piping for?
cold water, gas, irrigation.
(8.3) How do you check for cumulative microleaks?
use a helium mass spectrometer
(8.3) How do you check for combination-dependent leaks?
pressure, then vibration, then heat.
(8.7) How many microns are in 1 inch of mercury?
25,400
(9.2) Where is good ozone located?
stratosphere
(9.2) where is bad ozone located?
troposphere
(9.5) Why is July 1st, 1992 an important date?
it became illegal to intentionally vent CFC and HCFC refrigerants.
(9.5) When were CFCs phased out?
January 1st, 1996
(9.5) What is the GWP and ODP of CFCs?
high both of them.
(9.5) What are some examples of CFC refrigerants?
any R-10s like R-11 and R-12
(9.6) What is the GWP and ODP of HCFC refrigerants?
medium GWP, medium ODP
(9.6) When are HCFCs scheduled to be phased out?
by 2030
(9.6) What did the montreal protocol accomplish?
signed in 1987 to control the release of ozone depleting substances.
(9.7) Why is November 15, 1995 an important date?
it became illegal to intentionally vent HFC refrigerants
(9.7) What are some examples of HFC refrigerants?
R-134A, R-410A
