If the ignitor for an HSI sytem does not light after inducer start up, what is the proper action to check

Check low voltage at the pressure switch

The purpose of the burner crossovers is to

Provide smooth lighting for all burners

What is a redundant gas valve

Has multiple shut offs in series wired in parallel

What will occure if a technician comes into contact with voltage of a spark ignitor

The tech will experiance GREAT discomfort

Pipe dope should be applied to how many threads of gas pipe

All male threads less the two end

To test for an obstucted flue pipe what tool is used

A manometer to test negitive pressure

When determining a furnace has a failed heat exchanger a tech should do what

Shut down gas to that appliance and inform homeowner

The primary function of the high limit switch is to de-energize the

Gas valve if the sytem overheats

Flashback is an indication of what

Gas velocity is slower than it can burn

The fire stop on a dedicated vent system is located

Where it passes through the ceiling

Standing pilot nat. draft furnace has a bi-metal fan / limit control, what are the factory settings

Fan on 125 fan off 110 Limit 200

On an HSI furnace if the ignitor will not ignite, before changing make sure to check

The proper voltage to the ignitor

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Gas Heat ESCO (part 3 of 4) + Gas Heat ESCO (part 2 of 4) + Gas Heat ESCO (part 1 of 4)

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Questions 99

Answers

1
What condition would cause the temp safety switch to shut off the burners
Fan motor failure
Inducer or vent problem
Ignitor failure
Low gas pressure
2
A btu is an amount of heat required to raise one pound of water by how much
1C
100F
10F
1F
3
How much DC current does the flame sensor produce
1- 30 fullampiers
1- 30 microamps
1- 30 pecoamps
1- 30 sandwiches
4
Thermostat wiring comes in two different gauges, what are they
18AWG & 32AWG
16AWG & 18AWG
16STD & 18STD
12AWG & 14AWG
5
If the ignitor for an HSI sytem does not light after inducer start up, what is the proper action to check
Check gas pressure at gas meter
Check for proper voltage to ignitor
Check voltage at thermostat
Check low voltage at the pressure switch
6
For a DSI system the ignitor voltage is
5000V
10000V
100000V
1000V
7
A furnace installed in a garage should be installed _____ inches from the ground
18
24
12
30
8
Where is a "cut off plate" located on a FAU
At the top, duh
In the burner vestibule
On the blower housing
On the bottom near the air filter
9
What is the purpose of a flue baffle
Decrease heat
Provide total home comfort
Increase heat exchange
Lower fuel costs
10
A loud bang when the funace starts could indicate
Dirty burners
Dirty underwear
Dirty gas valve
Dirty thermostat
11
Blower temp / time delay switches are used to
Allow exchanger to warm up
Allow blower motor to heat up
Allow inducer to warm up
Allow vent gases to heat up
12
If you read zero ohms between the common and any speed on a motor, you determine the winding is
Grounded
Shorted
Hectored
Closed
13
The purpose of the burner crossovers is to
Provide smooth lighting for all burners
Provide smooth lighting for your ciggarette
It's not that necessary
Provide smooth lighting to just two burners
14
Nat gas pipe is sized to reduce pressure drops, what is the maximum allowable drop per the NFGC
.75in wc
.5in wc
.35in wc
1.2in wc
15
What is a redundant gas valve
Is dependant on a thermocouple
120VAC gas valve
Is a direct opening valve
Has multiple shut offs in series wired in parallel
16
What is the typical vent stack temp for a Nat. Draft CAT 1 furance
280F - 300F
350C - 450C
425F for 35mins or until golden brown
350F - 450F
17
What will occure if a technician comes into contact with voltage of a spark ignitor
It will only tickle for a moment
He'll cry like Hector
It will charge him with superpowers
The tech will experiance GREAT discomfort
18
What purpose does a "spoiler screw / adjustable shutter" serve for an atmospheric burner
To mix primary and secondary air
To mix secondary air and gas
To mix tramp air and gas
To mix primary air and gas
19
If a temp rise of 40F - 70F is required per the mnfr nameplate and the sytem has a temp rise of 80F what should be done
Call your senior technician
Decrease fan speed
Leave it alone it's working great
Increase fan speed
20
Metal wall B vent has an inner and outer pipe, what is the inner pipe made of
Aluminum
Steel
Silver
Brass
21
You start up and older furnace and find that once the blower comes on the flames waver and begin rollin out, you suspect
Faulty gas valve
Faulty heat exchanger
Faulty pressure switch
Faulty limit switch
22
What would cause the high limit safety to trip on a gas furnace
Bad outdoor fan
Coughing to loud
Bad indoor blower
Bad inducer fan
23
A description of how a bi-metal helical coil fan switch operates
Time on Time off
Gas valve on Gas valve off
Temp on Temp off
It works only weekends
24
Any furnace installed above ____ ft needs to have an adjust made to operate properly
200ft
2200ft
1850ft
2000ft
25
Whats the tool used to measure return airflow to a furnace
Vent hood
Blower door
Anemometer
Volt meter
26
If voltage is applied across to motor speeds what will happen
Noting happens
It will short out
It's Hectored replace it
The motor runs faster
27
What is the name opf the tool used to clean the burs after cutting black iron pipe
Magic eraser
Pipe cutter
Die
Reamer
28
The typical air temp rise for a CAT 1 furnace is
40C - 70C
40F - 70F
40N - 70N
40K - 70K
29
Liq petro ( propane and butane ) has a specific gravity of
2.0 - 2.5
.8 - 1.4
2.5 - 3.0
1.5 - 2.0
30
A nat. gas furnace requires ____ supplied to the gas valve and has a typical output of ____ to the manifold and orifices
7-9in wc and 4.5in wc
5-3.5in wc and 2.0in wc
5-7in wc and 3.5in wc
11-13in wc and 7.5in wc
31
Pipe dope should be applied to how many threads of gas pipe
Both female and male threads
All male threads less the two end
Lube should be applied liberally
All female threads less the two end
32
Round metal ducting needs to be insulated, when using duct wrap what R value is achived
30.0 R value
3.0 R value
4.5 R value
4.0 R value
33
To test for an obstucted flue pipe what tool is used
A volt meter to check volts at the inducer
A volt meter amp clamp to test the gas pipe
A manometer to test negitive pressure
A manometer to test gas inlet pressure
34
When brazing copper to LP gas line what solder is used
85 / 15 %
100 %
95 / 5 %
Rosen Core
35
When determining a furnace has a failed heat exchanger a tech should do what
Call your boss and request pricing
Turn off whole home gas supply
Send it and all should be just fine
Shut down gas to that appliance and inform homeowner
36
Furnace limit and safety switches are wired in series with
Blower motor
IFC
Gas Valve
T - stat
37
CO (carbon monoxide) is a very dangerous chemical, but what how much is acceptable in a sample of flue gas
.04%
.004%
.02%
4%
38
One cubic foot of liq petro burned produces _____ BTUs
900 - 1100
20000 - 25000
2000 - 2500
1500 - 2000
39
The primary function of the high limit switch is to de-energize the
Blower motor if the system overheats
Gas safety valve to stop gasflow
Gas valve if the sytem overheats
Gas valve if the blower comes on
40
Flashback is an indication of what
Gas velocity is faster than burn rate
Gas velocity is slower than it can burn
You drive slower than my grandmother
Gas velocity is a pointless thing
41
Black iron piping should be installed at a pitch of
1in per 15ft
1/4in per 15ft
5/16in per 15ft
1/14in per 10ft
42
The fire stop on a dedicated vent system is located
Three blocks down the street
Where is stops at an intersection
Where two or more vents are used
Where it passes through the ceiling
43
Gas valve with 100% shut off means what
Whole home gas is off
Pilot and manifold shut off
Gas to furnace shut off
Gas to pilot shut off
44
In order to properly burn one cubic foot of natural gas how much combustion air is required
14cu ft
15cu ft
10cu ft
8cu ft
45
Standing pilot nat. draft furnace has a bi-metal fan / limit control, what are the factory settings
Fan off 125 fan on 110 Limit 200
Fan on 125 fan off 110 Limit 200
Fan on 140 fan off 120 Limit 220
Fan on 110 fan off 125 Limit 210
46
Rectangular metal ducting tends to transmit noise to the conditioned space, how can that be reduced
Tape and bubble gum
A whole lotta of mastic
Slip connections
Flex connectors
47
A job calls for the installation of t-stat wiring at 75ft, to avoid voltage drop what size is needed
18AWG
18ADD
16AFK
16AWG
48
Single hook, ring and cleavis are all types of
Types of shower curtains
Sheet metal tools
Funny sounding names
Hangers to support gas pipe
49
On an HSI furnace if the ignitor will not ignite, before changing make sure to check
Your underwear
The proper voltage at the gas valve
The proper voltage to the ignitor
Check voltage at the t-stat
50
A condensing furnce must have a rating of _____ or higher
78% AFUE
80% AFUE
90% AFUE
96% AFUE
51
Whats the correct CHEMICAL name for natural gas
Octane
Butane
Methane
Farts
52
What is the total volume of flue gas produced by a Natural gas furnace with a draft diverter
30cu ft
10cu ft
25cu ft
35cu ft
53
When using an extention ladder the top should extend _____ above the roof line
3in
3ft
4ft
2ft
54
What is the reason for having an anticipator in a manual t-stat
There is no such thing
Reduce temp swing
Increase temp swing
Increase overshoot
55
A properly working thermocouple read on a DC meter will read
40 millivolts
30 millivolts
15 millivolts
20 millivolts
56
When cutting and installing 1/2" and 3/4" black iron pipe, how many threads should be cut
10 - 12
4 - 20
7 - 9
8 - 10
57
The serverity of an electric shock is determined by
The electric current flow and its path through the body
The total amount of voltage
The intensity of the current and voltage
The amount of voltage and its path through the body
58
When installing a gas furnace how many inches should be made avalible for service access
24inches
30inches
28inches
18inches
59
If a newer furnace shuts off before the rooms are warm
It's not that cold outside
Suspect the anticipator setting
Bad internet connection to t-stat
Suspect a bad gas valve
60
The "spud / orifice"
Meters the gas meter
Meters BTU output
Meters gas to burners
Meters the crossovers
61
What air is mixed in the burner prior to ignition
Tramp air
Secondary air
Bypass air
Primary air
62
When using the 10 wrap method the reading is 5.5amps, what should the anticipator be set to
.50amps
55amps
.055amps
.55amps
63
What does natural gas primarily consist of
Methane
Co2
Carbon
Water
64
Constant speed, constant torque and constant airflow are all typs of
CSCR motors
CSIR motors
ECM motors
PSC motors
65
A redundent valve used on furnaces shut down if pressure exceeds
13.5in wc
7in wc
10in wc
3.5in wc
66
What is the approximate ignition temp of natural gas
1250F - 1350F
825F - 925F
950F - 1025F
1100F - 1200F
67
The diameter of the burner widens before gradually narrowing to increase velocity pressure and aid in gas/air mixture
Due to the venturi
Thanks to the spud
It's called the choke
Due to the orifice
68
What does a GFCI circut break do
Detects leaks in plumbing
Dectects leaks to ground
Detects under current
Detects wierd smells
69
What tool is used for calculating carbon dioxide in flue gas
Combustion blower
Combustion analyzer
D - none of the above
Combustion triangle
70
If a furnace is "direct" ignition it
Energizes the blower before main ignition
Manually light pilot to start main ignition
Lights a pilot with an electronic ignitor
Lights main burners and electronic ignitor
71
What is the inlet supply pressure for LP ( propane ) gas
12in - 15in wc
5in - 7in wc
11in - 13in wc
9in - 12in wc
72
You come across an older furnace and it will NOT light, while checking voltage you find only 19vac on secondary
Stop buying tools at Harbor Frieght
Gas valve is faulty
Your meter is defect
Transformer could be faulty
73
If your pilot tubing / assembly becomes plugged, do you
Use solvent to clean it
Clean it
Replace the furnace
Replace it
74
Whats the normal range of flue gas temp for a CAT 3 furnace
370F - 420F
350F - 450F
280F - 300F
375F for 2hrs
75
What is the purpose of the gas regulator for a gas fired furnace
For ensuring proper inlet pressure
So the proper amount can be billed
To keep excess gas out
Maintain constant pressure to manifold
76
The venting of a condensing furnace is classified as
CAT 3
CAT 4
CAT 2
CAT 1
77
Any unit designed to be installed in different configurations is called
Bi -flow
Horizontal
Multiposition
Counterflow
78
In perfect combustion what percent of Co2 is present in flue gases
4.5% - 7.5%
2.5% - 5.5%
5.5% - 8.7%
6.6% - 8.3%
79
What is the name of the tool used to "cut" the threads of black iron pipe
Die
Reamer
Pipe cutter
Fly
80
What switch must operate before ignition trial begins on a system with an induced draft motor
Roll out switch
High limit switch
Ignitor relay
Air pressure switch
81
For heating the fan speed should be set by
What ever your boss says
It doesn't truely matter
The CFM on the data plate
The Temp rise on the data plate
82
The furnace nameplate specifies a temp rise of 40F - 70F yet you read 80F rise, what should be done to correct it
It's not to much higher leave it be
Replace the motor
Increase the blower speed
Decrease the blower speed
83
A tech services a LP furnace that had been converted from Nat. Gas and has a heavy amount of soot built up, but why
Burner to large
Gas valve is a beast
Orifices to large
Manifold to small
84
Normal voltage for an HSI ignitor is
120ACDC
120VAC
12VAC
1200VDC
85
Liquified Petroleum ( LP ) gas are
Regular and Unleaded
Propane and Butane
Natural gas and Methane
Liquid compressed natural gas
86
On a modern furnace with an IFC, how is the blower cycled during a call for heat
Time on time off
It works when it wants
Continuous fan on
Temp on temp off
87
Typical manifold pressure for an LP furnace is
3.5in - 4.5in wc
7in - 9in wc
4in - 6in wc
10in - 11in wc
88
Some times it is nessisary to increase vent size when installing a CAT 1 furnace, where is the proper location to adapt
At the roof termination
Does not matter
At the wall outlet
At the furnace connection
89
If you install a CAT 4 two pipe venting system how should the air intake terminate
How ever you can
Pointing up
Pointing down
Pointing towards your neighbors windows
90
Metal B vent flue piping has a clearance requirement of
6 inches
2 inches
1 inches
4 inches
91
If you're installing two sections of rectangular metal ducting, what connectors are used to securly fasten them together
S connectors and Drive clips
A whole lotta duct tape
Flexable connectors
A bucket of zip screws
92
What is the most common burner used in the modern furnace
Inshot
Outshot
Upshot
Ribbon
93
Homeowner complains of a loud bang on start up, checking outlet pressure you find it to be 3.2in wc what should you do
Check the thermostat
Check the gas company
Check the gas valve
Check your supply gas pressure
94
What is the "bonnet capacity" of a furnace
Output BTUs
Unknown term
HX model
Intput BTUs
95
When starting a gas furnace you notice flame "roll out" on ignition start up, you conclude
A faulty inducer motor
A faulty draft vent
A faulty rollout switch
A faulty pressure switch
96
How many BTU/hr will burning 1 cu ft of natural gas produce
900 - 1100
9000 - 11000
1200 - 1500
2000 - 2500
97
When soldering an electrical wire to a terminal what solder is used
85 / 15 %
Chewing gum
95 / 5 %
Rosen core
98
If you needed to change / adjust your motor speed on a belt driven motor / pully system, how do you achive that
Adjust the motor position
Adjust your spring tentioner
Whack it with a hammer
Adjust the blower pully
99
Furnace stops heating prior to satisfying the t-stat, and it only happens on cold nights. You adjust the GV and nothing
A defect gas valve regulator
A defective gas meter
A defective Ford Bronco
A defective day maid

Gas Heat ESCO (part 3 of 4) + Gas Heat ESCO (part 2 of 4) + Gas Heat ESCO (part 1 of 4) Flashcards | StudBud