res installs Flashcards
what is the fire triangle
fuel
heat
oxygen
_____________ is added to gas to smell and identify gas?
mercaptan
you need 10 cubic feet of air to burn _____ cubic foot of gas?
one
what is the purpouse of a gas orifice
the gas orifice is the fitting used to shoot gas into the burner
ignition temp for natural gas is?
between 1230-1360
propane ignition is?
920-1020 f
how many btu is required to take a solid to a vapour?
1314
at what tempurature will the furmace blower shut down at
90°f
low efficent furnaces is up to ___ efficent and vent temp is _____?
78% efficentcy and temp of vent is 450°f
mid efficent furnaces has a efficientcy of _____ and a vent temp off_____?
78% efficientcy and vent temp 350°f
high efficiency furnace is ________ efficient and vent temp is _____?
88% efficient and vent temp is 110°f
what is the proper name for pvc
polyvinyl chloride
what are the 4 styles of furnaces?
- upflow
- counter flow
- horizontal
- low boy
what dose CFM stand for?
cubic feet per minute ( volume of air)
what dose fpm stand for
feet per minute (velocity)
what is not required in a solid fuel furnace?
gas valve
what is the heating value of natural gas
1000 btu/ft3
what is the heating value of propane
2500 btu/ft3
what are high efficiency furnaces also known as ?
condensing furnaces
what is the heart of a hvac system?
air recirculation fan
the ratio between duct should should never exceed_______
4:1 ratio
how many feet of pipe dose a elbow add to a run?
10 feet
the under slab duct system may be secured with______?
slab stakes
what is the purpouse of slab steaks
to keep the duct of the bottom of the trench and is to keep the duct from floating up when concrete is poured
in a underslab ducting system which way should youre duct be slopped
back to the furnace
system 636 is also known as
bh vent
what is galvalume?
galvalume is steel coated with 55% aluminium and 45% zinc
a flexible insulated duct is covered with __________ and a __________ ?
insulation and a plastic vapour barrier
whaf is the purpouse of putting a termination kit at the end of a combustion air duct?
to keep cold air from dropping into the furnace room excessively
what is exfiltration
exfiltration is the uncontrolled leakage of air from a building
what causes dynamic loss
type of material
shape of duct
changes in direction
changes in cross sectional area
dynamic losses are approxmatley ___ times as much per foot travling through flexible duct as it dose in smooth duct
10 times
what kind of duct is the most efficient shape and should be chosen when ever possible
round duct
furnaces requires are to fuel the fire inside of them. this is called _____________
combustion air
both factory built chimneys and vents have a system of parts that are ____________ by a recognized testing agency
certified
you should always install 2 elbows back to back… true or false
false
oh&s covers who?
employers and employess
all furnaces installed must ber certified by whom
csa
what is required to do a heat loss calculation on a building
a set of blue prints
what dose the heat loss calculation determine whrn completed
size of furnace required
what is the purpose of a fire stop?
to stop fire from entering the chase and to maintain the clearance
what is the gas code we follow
b149.1
supply outlets is what minnim clearence from the ground
12 inches
in addition to moisture what else dose the range hood remove?
airborn greases and oils
dryer runs should always be _________ and never _________?
taped and never screwed
how many feet dose a mechanical hood be installed from a gas regulator
and how many feet can a natural draft intake or appliance exhaust hood be installed from a gas reg
- 10 feet
2. 3 feet
the clearence for the front of the furnace should be ?
24 inches or 2 feet
which agency conducts tests and writes standards specifically for the hvac industry
SMACNA
whose responsibility is it to ensure the job is done properly abd to the applicable code
the installer
how far from there furnace inlet dose the fresh air connection be installed
10 feet
if a metal joist liner is installed you should ____ gap to reduce noise
1 8th
typicaly you reduce every___________ cfm
400
