Core Exam Flashcards
(27 cards)
What kind of construction is pier and beam used for?
Crawl spaces and Elevated homes
Trusses are held together by what?
Cleats and Gusses
How many busses and cleats are used to hold a truss?
1 Gus and 2 cleats
What kind of flame is best for brazing?
Neutral flame
What kind of flame is not good for brazing
oxidizing and carbonizing flames
what kind of gas is acetylene gas?
Flamable gas
what does flux do?
stops oxidation inside and outside the tubing surface
when should you use flux?
dissimilar metals. Copper to brass
what is the proper way to make a flare
tighten 1/2 turn, back off 1/4 turn, tighten 3/4 turn, back off 1/4
what kind of threads does a tap make?
female threads
what kind of threads does a dye make?
male threads
how do you properly care for snips
wipe with oiled rag
what do you use to adjust duct strap tool (pantsuit tool)
the cam on the tool
what are the two bubbles on a level for?
plumb (vertical) and level (horizontal)
what is an opinion?
a view or judgement
what is a fact
absolute truth
what is jargon?
trade terminology
3 is what percent of 5
3/5= .6 * 100 = 60%
what is the volume of air (CFM) coming from a 80,000 btu furnace with 140 degree supply and 60 degree return temps?
CFM = BTU/(DELTA T * 1.08) = 926 CFM
a cleaning solution mixes 4 parts water 1 part solution 4:1
how much solution is needed if you want 20 gallons
4+1=5, 20/5 = 4 gal
what is the max fill percentage of a refrigerant cylinder
80%
what is the max temp a refrigerant cylinder can be kept at?
125 degrees
is refrigerant heavier or lighter than air?
heavier. it displaces oxygen
how many cubic ft of air weighs 1 lb
13.33 cu ft
