問題一覧
1
what must be in an attic to allow work
a catwalk minimum 18 inches and adequate lighting available
2
what agency approves ladders
OSHA
3
will you encounter asbestos in customer homes
yes
4
are traffic cones necessary when parking in a parking lot
yes
5
how much is 1 therms
100,000 BTU
6
what does BTU stand for
British thermal unit
7
what is the specific gravity of natural gas
.60
8
what is the specific weight of air
1.0
9
is gas lighter than air
yes
10
what are the explosive limits
4.5%-15%
11
when is gas too rich to explode
above 15%
12
when is gas too lean to explode
below 4.5%
13
what is odorant
a smell added to odorless gas
14
what is odorant made up of
50% mercaptan 50% thiophane
15
what are the components needed for complete combustion
fuel, air, temperature, time
16
what is primary air
air mixed with the gas prior to combustion
17
what is secondary air
air in the atmosphere surrounding the flame
18
what are the products of complete combustion
carbon dioxde, water vapor, heat
19
what are the products of incomplete combustion
carbon monoxide, soot, aldehydes
20
indication of carbon monoxide
soot on appliance, melted wires, aldehyde odor,
21
physical symptoms of carbon monoxide
puking, headaches, unconscious,
22
what causes floating flame
lack of secondary air, obstruction in heat exchanger, or restriction or secondary air inlets
23
what cause we lifting/blowing flame
excess of primary air, primary air shutter may be too open, pressure to high
24
what causes soft/yellow flame
lack of primary air, dust & lint in Venturi throat
25
what is flame roll out
a type of floating flame, lack of combustion air
26
1 CF of gas = how many BTU
1,000
27
what is the ignition temp of natural gas
1100-1300 F
28
gas to air ratio for a proper flame
10 CF air to 1 CF gas
29
is a tall yellow flame complete or incomplete
complete if the flame is not obstructed
30
is a floating flame complete or incomplete
incomplete
31
what does a thermostat do
regulates temperature by turning the appliance on and off automatically
32
what does a pilot do
provides a source of ignition to the main burner & maintain heat on a “safety” device (the magnet)
33
what does a main burner do
allow ignition & combustion @ the burner ports to contain a stable flame & mix gas/air prior to ignition
34
what are controls
they control the flow of gas to the main burner (some have safeties)
35
what are safeties
a device that stops the flow of gas to the main burner if the pilot goes out
36
what is a 90% safety
when gas goes to the pilot but shuts off at the main burner
37
what is 100% safety
when gas is shut off to both pilot and main burner
38
do manual light ovens have a safety
no
39
do thermostat controlled appliances require a safety
yes
40
what does ASO stand for
automatic shut off
41
what do vents do
allow products of combustion to vent outside
42
do stoves/ranges/ovens need to be vented
they do not
43
what does a heat exchange do
converts fire from gas into a usable form
44
what do fans/blowers do
move the heated air to wherever it is needed
45
what does an appliance rating tag show
fuel type, btu, clearance to combustibles, model #, vent information
46
how long must it take a safety device to shut down after pilot outage
within 2 minutes
47
what does a thermocouple do
energize magnetic safety systems
48
what type of safety is a pilot generator
100% safety
49
what does an interrupter valve do
blocks the flow of gas to the main burner while lighting a pilot
50
what are indications of an electric pilot
orange/thick wires, ceramic around pilot
51
what is combustion air
primary and secondary air
52
what is a combustion air opening
opening to allow combustion air to enter near appliance
53
what is circulation air
air fan pushes through ducts
54
what does a fireblock do
separate combustion and circulation air
55
what does a draft diverter do
prevent downdraft, excessive updrafts, moderate stack temperature
56
why is updraft bad
could pull flames off burner and cause incomplete combustion
57
what are the vent types
A- masonry and Transite b- insulated or dual wall sheet metal C- single wall sheet metal
58
what clearance does vent type A require
0 inches
59
what clearance does vent type B require
1 inch
60
what clearance does vent type C require
6 inches
61
what does a vent cap do
prevent downdraft and keeps debris and elements out
62
what are the 3 main vent system requirements
cap, draft diverter diverter, vent pipe
63
what if there is duct tape on vent system
if charred, shut down and tag; if in good condition, leave appliance on but tag unsatisfactory
64
what is the purpose of foil tap
temp fix to close small gaps/holes
65
can foil tape be used to secure vents
no
66
where do dryers need to be vented
outside
67
what to look for in visual vent inspection
transitions, gaps/cracks, double draft diverters, rust/corrosion, proximity to combustibles, duct tape/foil tape
68
are double draft diverters allowed
nope
69
how to secure type C venting if loose
sheet metal screws
70
how to secure type B venting
snap connectors and require a draft hood
71
what if type b vent has no draft hood
match test all the small holes on snap connectors
72
can vents run through recirculating air chamber of FAU
nope
73
what do dial #s represent on a meter
cubic feet
74
why do you do a registration chevk
check for leaks, verify the meter is registering, and general safety
75
what is the max allowable registration for pilot load
2 cubic feet per hour
76
test time for 1/2 ft dial
90 seconds
77
test time for 2 ft dial
6 min
78
what are the height requirements for non FVIR WH in garage
18 inches
79
what is common venting
when two appliances are vented together
80
what category vent can be common vented
category 1
81
can a category 1 appliance be vented with a category 3 appliance
no
82
when can you stand on top of a ladder
when there is secure firm hand holds
83
1 therm = ___ CF Gas = 100,000 BTU
100
84
how does a T n P valve need to be plumber
plumbed down (and away)
85
how do you check venting on common center appliance
they need to be checked individually and while both running
86
where is vent information found
on the rating tag
87
do all water heaters require a TnP valve
yes
88
what is the max temp we can set a water heater to
120 F
89
do you match test direct vent systems
no because there is no draft diverter
90
what is ECO
energy cut off
91
what do ECOs do
interior the circuit to the safety when overheated
92
where are ECOs found
in the control valve (new FVIR heaters have them built into thermocouple)
93
what can clogged FVIR screens result in
floating flame
94
what is required on WH to secure them
earthquake straps
95
sources of circulating air for FAU
outside building, rooms being heated, or combo
96
prohibited sources of circulating air for FAU
in the same confines space as the combustion air inlet, garage, not within 10ft of other vent outlets
97
closet FAU air requirements
combustion & circulating air need to be seperated
98
combustion air supply formula
rated BTU divided by 1000 times 2 equals air opening size in sq in
99
Is propane heavier than air
yes
100
what does a spill switch do
detects products of combustion through draft diverter due to non venting and shuts appliance off