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Gas (A-book) Flashcards

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1
Q

What are the 2 primary categories of burners?

A

Non-mechanical
Mechanical

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2
Q

How are the 2 types of burners distinguished?

A

By how the combusion air is supplied

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3
Q

What is a non-mechanical burner?

A

atmospheric burner
relies on natural draft to supply the required combusion air
Less common as they have lowefficiency / more susceptible to flue gas spillage.

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4
Q

What do appliances today use to ignite the main burner?

A

The burner is ignited directly by a spark or hot surface igniter

Installer needs to be familiar with the service / troubleshooting procedures

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5
Q

What are 3 things a control system of an appliance must do?

A

1) Initiate a safe light-up
2) Supervise the run period
3) Provide a safe shut down

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6
Q

What is unique about appliance controls?

A

They are individual components of distinct circuits w/ specific functions

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7
Q

What does the Combustion safety circuit include?

A

Thermocouple and safety shut off valve

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8
Q

What does the main burner control circuit include?

A

Thermostate, high temperature limit / main gas valve.

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9
Q

What are indoor non-vented gas appliances mainly used for?

A

Cooking equipment

Commercial kitchens = large exhaust fans = adequate air exchange

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10
Q

What happens if non-vented appliances w/ no vent hood are used for a long time?

A

Contributes to poor air quality

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11
Q

True or False: Unvented gas space-heating appliances can be used indoor.

A

False: they cannot

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12
Q

How does air exchange work for a direct vent system?

A

Air is taken directly from outside
flue gas is taken directly outdoors

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13
Q

What are the 2 piping - options for a direct vent system?

A

Concentric coaxial pipe
twin pipe

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14
Q

How does a coaxial vent work?

A

Combustion air + exhaust flor directly through a single connection to appliance.
Hot exhaust exist –> interior tube
Combustion air enters –> outer layer

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15
Q

What is a Thermal Trap?

A

Combustion air pot
Prevents loss of heated air when equipment is not firing

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16
Q

How do Direct Fire Heaters work?

A

Has exposed flame (like a grill)
Combustion products added to air

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17
Q

Can Direct fired heaters be used for places where people sleep?

A

Nope

Combustion products are not well contained…
No homes, hotels or clinic

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18
Q

Why must a range not be installed in a bedroom?

A

Because of the possibility or producing carbon monoxide

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19
Q

If a range is not used as a space heater can it be installed in a bed-sitting room?

A

Yes

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20
Q

What are 5 factors to be considered when installing a gas range?
(CLARS)

A

1) Specific instal requirements -> manufacture’s instructions
2) Leveling the range
3) Anti-tipping devices
4) Restraining device for commercial cooking appliance on wheels
5) Clearance to combustibles.

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21
Q

What are 4 specific install requirements for a gas range?
(CAPP)

A

1) Clearnace to combustable requirements (manu. instruc. / rating plate / applicable codes)
2) Access for cleaning, repairs / servicing
3) Proper distance to venting hoods, flues or ductwork
4) Proper positioning

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22
Q

What are 4 basic components to an absorption refridgerator?
(GACE)

A

1) Generator (Boiler)
2) Condenser
3) Evaporator
4) Absorber

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23
Q

Why arn’t Recessed wall furnaces common for new installations?

A

They are natural draft units –> require special oval (BW vent) configuration designed to fit inside a stud wall

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24
Q

What are High-Intensity infrared heaters, burners made with?

A

Porous material like ceramic or metallic screen

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25
Q

What is the surface temp of a high-intensity infrared heater?

A

980 C or 1800 F
This temp helps retain the flame on the surface => increasing radiating efficiency.

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26
Q

Are high-intensity units vented or non-vented?

A

Non-vented => makes usage restricted

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27
Q

Where does the combustion occur in Low-intesity infrared heaters? (aka tube heaters)

A

In tubes or panels
Made of metal or ceramic

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28
Q

What type of gas fireplace is avoided in Canadian housing?

A

Vent-Free gas Fireplace
(is available in the US)

NOT APPROVED IN CANADA

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29
Q

Gas storage water heaters have the option of 4 types of vents to use, what are they?
(NDPP)

A

1) Natural vent
2) Direct vent
3) Power vent
4) Power direct vent

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30
Q

What does FVIR stand for?

A

Flammable Vapour Ignition-Resistant

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31
Q

What are the 5 components of the FVIR burner?
(SR. SUP)

A

1) Stainless steel flame arrestor plate
2) Resettable thermal cut-off
3) Sight glass
4) Upshot multiport burner
5) Piezo ignitor

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32
Q

What does the stainless steel flame arrestor plate actually do?

A

Provides a one-way path for air to travel through

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33
Q

What does a Resettable thermal cut-off do?

A

It shuts the gas flow to the pilot / burner if flammable vapours enter the combustion chamber / ignite

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34
Q

What does a Sight Glass do?

A

Provides view of the operation of the pilot / burner in the sealed chamber.

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35
Q

What does a Piezo ignitor do?

A

Ignities the pilot burner in the sealed chamber

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36
Q

What stage can a furnace be?

A

1) single stage
2) two-stage
3) multi-stage (modulating) model

This means that it can be combined w/ heat pump, solar system, AC

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37
Q

Condensing boilers are constructed w/ what?

A

More heat exchanger surfaces
made of stainless steel or aluminum

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38
Q

How efficient are condensing boilers?

A

98% – very high
conventional boilers = 87%

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39
Q

True or False: A pump can move pressurized steam through boiler piping.

A

True

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40
Q

What happens when there is a discrepancy bn manufacture info / codes?

A

The most stringent requirments shall prevail

AHJ can provide guidance

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41
Q

What happens when there is a discrepancy bn manufacture info / codes?

A

The most stringent requirments shall prevail

AHJ can provide guidance

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42
Q

What info will be on a rating plate?
(There’s 16 points :S)

A

1) Approvals (regulating authorities / agencies)
2) Input rating
3) Heat output (BTU/h, LPH, LB/h)
4) Approval altitude
5) Gas supply pressure (min/max)
6) Gas manifold pressure (high fire/low fire)
7) Orifice size
8) Temperature rise
9) Static pressure range (forced air furnaces)
10) Max water pressure (boilers / w.h)
11) Max water temp (boilers/ w.h)
12) Min relief valve capactiy (ib/h steam or btu/h)
13) Appliance clearance
14) Operating voltage / current
15) Max overcurrent protection
16) Electric motor HP

WH = water heater

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43
Q

What happens when there’s no national standard for a special gas equipment?

A

Inspection body accredited by Standards Council of Canada is permitted to apply an approval label –> known as a “field approval”

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44
Q

What equation do we have to remember?

A

45 GPH x 8.33 lb/US Gallon x 90 F T= 33,737 BTU/h

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45
Q

All installations must conform to requirements of…

A

applicable building, gas / electrical codes
Part 7 (specific types of appliances) and 4 (general requirements) of CSA B149.1

Look over those parts when installing any gas appliance

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46
Q

Why does the Canadian Standards Association (CSA) exist?

A

To develop standards

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47
Q

What does the CSA B149 Gas Code Series provide?

A

Important guidance on how to do your job as a gasfitter safely
(from handling / storage of NG / propane –> the safe / effective installation of related appliances / equipment)

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48
Q

Which crowd does CSA B149.1 target?

A

Canadian gas / propane industry workers

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49
Q

CSA B149.2 Holds what secrets?

A

The latest advances in industry best preactices / most current safety requirements.

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50
Q

CSA B149.3 is Code for..

A
  • For the Field Approval of Fuel-Related Components on Appliances / Equipment
  • It provides requirements for:
  • fuel -related components / accessories
  • assembly on appliances / equipment using gas
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51
Q

CSA = across Canada
Each province maintains their own what?

A

Regulation, licensing / registration of gas in various ways

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52
Q

Technical Safety BC put in place for public safety by creating rules in what areas?
(there’s 8)

A

1) NG / propane appliances/ systems
2) Boilers, pressure vessels / refrigeration systems
3) Passenger ropeways –> aerial trams / ski lifts
4) elevating devices –> elevators / escalators
5) electrical equipment / systems
6) Alternative safety approaches
7) Amusement devices
8) Railways

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53
Q

Who performs gasfitting work in BC?

A

Certified gasfitters

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54
Q

Who is allowed to pull a gas permit?

A

Registered gas contractor

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55
Q

True of False: Gas installations permits can be pulled after work begins

A

False: Gas permits must be obtained before any work begins

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56
Q

Who is The Safety Standards Appeal Board?

A

Created by Safety Standards act
Appeal board: can review certain TSBC decisions when clients request a review.

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57
Q

The safety Standards act authorizes TSBC to what in the face of non-compliance

A

take enforcement

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58
Q

What products / work regulated are under the Standards act?

A

1) boilers/ systems
2) Electrical systems / equipment
3) Elevating devices / passenger conveyors
4) Gas system /equipment
5) pressure vessels / piping, refridgeration system/equipment
6) Amusement ride
7) Ski lifts

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59
Q

who does the gas safety regulation apply to?

A

Everyone who installs, alters, maintains or operates gas technologies in BC

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60
Q

What are Safety Orders?

A

They are instruments that are issued to prevent or reduce the risk of person injury or damage to property.
Compliance is mandatory and enforceable by TSBC

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61
Q

What is section one about in the gas code?

A

Scope –> mostly installation

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62
Q

What is section 2 of the gas code?

A

Reference Publicatons –> codes or standards that govern equipment, components methods or materials cited in the code.

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63
Q

What is section 3 of the B149.1 about?

A

Definitions

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64
Q

What’s included in Section 4 of the gas code?

A

General –> explains the general application of the gas code

65
Q

What is Section 5 of the gas code?

A

Pressure Control

66
Q

What does Section 6 of the Gas Code include?

A

Piping and Tubing systems, Gas Hose / Fittings

67
Q

What is Section 7 of the Gas Code about?

A

Installation of Specific Types of Appliances

68
Q

What is Section 8 of the Gas Code?

A

Venting Systems / Air Supply for Appliances

69
Q

What are the 3 requirements for combustion to occur?

A

1) Fuel
2) Heat
3) Oxygen

70
Q

What are the ignition temps of NG, Propane / Butane?

A

NG = 1300 F - 700 C
Propane = 920 F - 495 C
Butane = 900 F - 480 C

71
Q

What is produced when hydrocarbons are combined with oxygen to create combustion?

Fire tetrahedron

A

Carbon Dioxide, Water Vapour, Heat

72
Q

The source of oxygen (for appliances) is air, what components are in air?

A

Oxygen = 20%
Nitrogen = 79%
Other = 1%

73
Q

What are the 3 types of combustion?

A

1) Perfect combustion
2) Incomplete Combustion
3) Complete Combustion

74
Q

Why is perfect combustion only theoretical?

A

Because most gas burners are not capable of mixing the exact gas / air volumes together to produce complete combustion

75
Q

What type of gas is Nitrogen

A

It is an inert gas.
Remains stable / will not chemically react (as long as temperatures are not too high)

76
Q

What chemical produces soot?

A

Carbon

77
Q

What does soot indicate (most of the time?)

A

An idicator of incomplete combustion
(the absence of soot does not = complete combustion)

78
Q

Why is Carbon Monoxide deadly?

A

Because it is colourless, odourless / tasteless gas
Small quantities inhaled can cause death

79
Q

What are the 3 main categories of Air supply (for gas appliances)?

A

1) Combustion air (theoretical)
2) Excess air
3) Dilution air

80
Q

What is Primary Air?

A

The combustion air that is mixed w/ fuel gas before the ignition point

81
Q

For a non-mechanical burner, what is the amount of primary air used?

A

1/3 of combustion air

82
Q

Is the primary air used in a mechanical burner higher or lower than non-mechanical burners?

A

Higher

83
Q

Where is second air supplied from and what is it’s purpose?

A

Supplied at the flame
Required to complete combustion
Is the other 2/3 of the combustion air required for perfect combustion

84
Q

To ensure that all fuel is completely burned, what is added?

A

Excess air

85
Q

How much excess air is needed for mechanical burners to achieve complete combustion?

A

20 - 30% excess air

86
Q

How much excess air do atmospheric burners require?

A

50% excess air

87
Q

Modern High-efficient appliances have significant lower flue - gas temp. What does that mean for Draft control devices?

A

They will not have a draft control device b/c they do not require dilution air.

88
Q

What 2 ways create Draft Movement?

A

1) Naturally (aka natural draft)
2) Blower (aka mechanical draft)

89
Q

Why must the amount and force of draft be controlled?

A

For combustion efficiency

90
Q

What happens when a draft is too strong

A

It will pull too much combustion air = affects the efficiency of the appliance

91
Q

Why are Power Venters used?

A

They are used to overcome venting problems
(ex: extra-long vents, excessive negatie pressures or improper venting design)

92
Q

Where is the fan or blower located on a Forced-Draft Burner?

A

Located upstream of combustion zone

93
Q

Under Appliances in the gas code, what are the different Categories?

A

Category 1: Flue loss = min 17% / negative vent static pressure
Category 2: Flue loss = max 17% / negative vent static pressure
Category 3: Flue loss = min 17% / positive vent static pressure
Category 4: Flue loss = max 17% / positive vent static pressure

Static pressure = atm pressure inside the duct

93
Q

Under Appliances in the gas code, what are the different Categories?

A

Category 1: Flue loss = min 17% / negative vent static pressure
Category 2: Flue loss = max 17% / negative vent static pressure
Category 3: Flue loss = min 17% / positive vent static pressure
Category 4: Flue loss = max 17% / positive vent static pressure

Static pressure = atm pressure inside the duct

94
Q

What is Backdrafting?

A

The reverse flow of gas in the flues = intrusion of combustion by-products into the living space

95
Q

What is the building envelope?

A

Is the physical separator bn the conditioned / unconditioned environment

96
Q

Why is the control of air flow important?

A

to ensure indoor air quality

97
Q

What happens in a Loose Building Envelope?

A
  • allows more natural gas transfer
  • building is draftier = uncomfortable / harder to regulate temp
98
Q

What happens if there is a Tight Building Envelope?

A
  • allows a high level of control over air quality, temp. humidity levels / energy consumption
99
Q

What is the main method used to control indoor air quality?

A

Ventilation –> removes indoor contaminants

100
Q

What is Soil Gas?

A

the mixture of air, water vapours / pollutants

101
Q

What happens when air enters a dwelling through below grade?

A

Can increase water vapour content of indoor air / number of pollutants picked up from soil

102
Q

What is a colourless, odourless, radioactive gas?

A

Radon

103
Q

What is necessary to reduce radon?

A

a subfloor depressurization system
(a measure required by the BCBC)

BCBC = BC Building Code

104
Q

Why is Make-up Air required?

A

To offset air removed by appliances with large exhaust fans

105
Q

What must the building depressurization be at if a building contains any natural draft gas appliances?

A

5 Pa => eliminates risk of backdrafting

106
Q

Where must outside air intakes be located ?

A

Away from sources of contminants and shielded from weather
(ex: vehicle exhaust or chemical vapours)

107
Q

What is the fan size / air-flow based on?

A

the number of bedrooms / floor area of the dwelling

108
Q

What is the most common method of recovering heat energy?

A

By preheating the ventilation supply air w/ exhaust air using a heat recovery ventilator

109
Q

What are the 2 common methods of gas appliance air supply?

A

1) Direct-vent system
2) Room air systems (aka non-direct vent)

110
Q

Why must mechanical air supply be properly sized / interlocked w/ appliances?

A

In order to shut off the gas in the event of air supply failure

111
Q

What does section 8 of B149.1 Gas installation Code regulate?

A

Details the installation / sizing of passive combustion air supply openings / ducts

112
Q

What is the most common pressure-measuring instrument?

A

Bourdon tube pressure gauge

113
Q

What do pressure meters, pressure gauges or vacuum gauges have in common?

A

They are instruments used to measure / display pressure using integral units.

114
Q

What is differential pressure?

A

the difference bn 2 contained working fluids

115
Q

How many inlet ports do differential pressure guages have?

A

2

116
Q

What can differential pressure gauges be used to monitor?

A
  • air flow
  • amount of filter clogging
  • Test equipment operation
117
Q

What is the simplest version on the fluid manometers

A

U-tube manometer
The tube half full of liquid / both legs open to atm –>level is the same on both sides

118
Q

How is duct air flow measured?

A
  • special tips are inserted into ducting via 9mm drilled holes
  • Tips connected to pressure measuring instruments via silicone rubber tubing
119
Q

What is the freezing point of water?

A

0 C - 32 F

120
Q

What is the boiling point of water?

A

100 C - 212 F

121
Q

How can there be more accurate readings from thermometers?

A

Longer the stem length = smaller the graduations can be

122
Q

Dial stem thermometers use what style of temp sensing element in the stem?

A

Bimetallic

123
Q

How are permanently installed thermometers mounted?

A

Mounted in a Thermowell (cylindrical fitting) –> closed at one end / mounted in the process stream

124
Q

What does the Thermowell protect?

A

The sensor from the process fluid
If the sensor fails, it can easily be replaced w/o draining the vessel or piping.

125
Q

True or False: Digital thermometers have better accuracy / larger temp range.

A

True

126
Q

What type of material is RTD made of and why is it important?

A

Pure material (platinum)
Has a near linear resistance change w/ temperature

127
Q

What is a thermistor?

A

Is a resistance sonsor that changes its resistance in a non-linear way.

128
Q

How does the thermistor differ from a RTD?

A
  • Thermistors are more sensitive to small temp changes
  • have a quicker response time
129
Q

Which type of thermocouples are used on digital multimeters?

A

Type K
It has a temp setting in selector dial
Uses conversion formula to convert output voltage level –> temp

130
Q

What is the modern pyrometer?

A

A device that can determine the temp of a surface from a distance (does not need contact of surface)

131
Q

How do portable dial thermimeters get out of calibration

A
  • from the presence of mechanical linakes
  • Being dropped
132
Q

What is the Freezing point method?

A
  • Simplest / most accurate
  • fill glass w/ ice and add clean water + stir
  • Wait for 3min + insert sensor
133
Q

What is the boiling point method?

A

Reading should hold steady at 100 C if below 300 m in elevation.
Higher elevations will have lower boiling temps

134
Q

How do you calibrate a dial thermometer?

A

There’s a calibration nut on back on the dail head
Hold nut securely w/ wrench / rotate head until read correctly
Other styles = separate adjustment or reset screw

135
Q

What does distance-to-spot (DS) ratio mean?

A

Distance (d) icrease = Spot Size (s) –> unit becomes larger

136
Q

How do you get an accurate measurement from a D:S?

A

Make sure target is larger than unit spot size
Smaller the target = closer thermometer should be

137
Q

How do you get accurate readings if there is a shiny metal surface? (d:s)

A

Surface measured can be covered w/ electrical tape or flat black paint.
Some intruments have an adjustable emissivity (can be finetuned)

138
Q

What is voltage drop?

A

The potential difference bn 2 points in an electrical circuit

139
Q

What is an Ammeter used for? (electrical)

A

to measure current in an electrical circuit

140
Q

How does current work?

A

It flows through a circuit when a power source is connected to a device or load

141
Q

What is current?

A

The flow of electrons in a circuit when voltage is applied to the circuit

142
Q

What is current a measure of?

A

Amperes (A) –> Amp
Milliamperes (mA)
Microamperes (uA)

143
Q

What is required when using a DMM to measure current (amps)?

A

Requires connecting the meter in series w/ the circuit being tested
(the meter would then be apart of the circuit)

144
Q

What does clamp on current probe accessory do?

A

measures higher values / safely take current readings w/o opening a circuit.

145
Q

What does the ohmmeter function on a DMM do?

A

The current flows through the tested circuit’s resistance
When set to ohms the DMM must not be on an energiezed circuit

146
Q

What does OL (infinity) indicate on a DMM?

A

Faulty fuse

147
Q

What should you do before you connect a meter to a circuit?

A

Ensure that the meter is on the right setting.
When in doubt use high range (will not overload then)

148
Q

AC and DC voltmeters must be connected how?

A

In parallel with the device or circuit being measured.

149
Q

Voltage measurement page 55

A
150
Q

What are the 2 common methods of measuring current using DMM

A

1) in-line ammeter method
2) clamp-on ammeter method

151
Q

AC current uses what method?

A

Clamp on method

152
Q

Current measurement w/ clamp on page 58

A
153
Q

Why is it important that while using an ohms meter the circuit must not be live

A

the battery supplies the current flow that is eventually measured by the meter

154
Q

The display will show what on an ohms meter when the test leads are clipped together?

A

0 ohms sign

155
Q

What type of sensor does not have to be placed into gas to detect it?

A

Infrared sensors
Can be used remotely at distances up to 30 meters

156
Q

When there is a propane leak, should you investigate high ground or low ground first? why?

A

Low locations first.
Propane is heavier than air

157
Q

What would indicate an outside below-grade leak?

A

If readings are strong but the smell is weak

Plumbing Level 2 (8 decks)

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