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G2 > G2 Test Questions > Flashcards

G2 Test Questions Flashcards

1
Q

Underground piping or tubing shall be tested in accordance with the:

A

Requirements of the B149. 1 Code

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2
Q

What is the allowable maximum distance piping supports should be spaced on a 4 inch horizontal gas line?

A

15 feet

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3
Q

What is the required minimum distance a purge line may terminate from either a building or air intake when purging a piping tubing system to outdoors?

A

10 feet

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4
Q

Schedule 80 piping is required in a propane system:

A

For propane vapour over 125 pisg working pressure

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5
Q

What is the minimum time and pressure required to test a new welded 3 inch NPS piping system that is 220 feet long with a supply pressure of 40 psig?

A

180 minutes at 60 pisg

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6
Q

Above ground piping of which size and larger must be welded, unlesss the authority having jurisdiction allows threaten joints?

A

2 and 1/2”

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7
Q

What size tubing is required to supply propane to a 225,000 Btuh input appliance when installing 95 feet of copper tubing which will operate at 2 psig with a pressure drop of 1.0 psig?

A

0.625” (5/8”)

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8
Q

When is it necessary to purge every branch supply line in a piping system?

A

Always

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9
Q

When sizing a branch line, what is the minimum size of job fabricated welded fitting that can be used on NPS 6” gas supply header?

A

3/4” NPS

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10
Q

Natural gas piping in industrial building shall be identified:

A

With yellow paint or yellow bands

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11
Q

When sizing a brand line, what is the maximum size of job fabricated welded fitting that can be used in a 4” NPS gas supply header?

A

2” NPS

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12
Q

Armoured cable is called”

A

BX

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13
Q

When a new appliance is to be installed in a building using steel framing and steel studs and the supply wiring to it will be in contact with the studding. Which of the follow types or wire is acceptable, and the most cost effective?

A

BX

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14
Q

Voltmeters are connected:

A

In parallel with the device being checked

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15
Q

A panel mounted ground fault circuit interrupting breaker protects all:

A

Loads in the circuit served by that breaker

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16
Q

A hard, sharp pilot flame indicates:

A

The orifice is too small

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17
Q

A good pilot generator should produce what voltage?

A

750 mV

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18
Q

Which of the following statement is correct?

A

A ground wire shall not be used as a neutral wire

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19
Q

A zero ohmmeter reading tank between the casing of a solenoid and disconnected wire to the solenoid indicates that:

A

The coil is shorted to the casing of the device

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20
Q

The instrument used to determine potential difference in an electrical circuit is the:

A

Voltmeter

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21
Q

As the diameter of a wire increases the resistance:

A

Decreases

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22
Q

In a normal thermocouple application, the expected drop out reading is from:

A

2-4 millivolts

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23
Q

The resistance of a wire ___________________ as its temperature rises.

A

Increases

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24
Q

What is the percentage of the appliance-rated gas is applied to a burner using a two stage gas valve when the thermostat calls for the second stage of heat?

A

100%

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25
Q

An intermittent pilot is present:

A

Only until the main burner is lit

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26
Q

Thermostats are selected and rated to switch:

A

All of the above

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27
Q

Burner interlocking flow switched are generally used on boilers which have _________________ water capacities.

A

Small

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28
Q

A combustion gas valve contains:

A

A manual shut off valve an automatic gas valve, a pressure regulator

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29
Q

A hot surface ignitor requires ___________ volts to operate properly.

A

115 - 125 VAC

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30
Q

Trial for ignition is the time allowed to:

A

Establish ignition

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31
Q

What happens to the current flow through an infrared scanner when the scanner is exposed to infrared radiation?

A

Current increases

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32
Q

Which of the following heating systems would be expected to cause problems due to this “distribution effect”?

A

A forced air furnace with no return openings in the furnace room

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33
Q

The key components of a building as a system are:

A

The building envelope, external environment, mechanical systems, and the occupants39.

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34
Q

Conduction is:

A

The transfer of heat particle to particle

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35
Q

Currently, the most common type of building construction is:

A

Platform

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36
Q

To ensure the main burner cannot operate unless the dampers are in the fully open position, electrically operated automatic combustion air dampers shall be:

A

Interlocked with the burner control system

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37
Q

A depressurization test conducted on a house will help determine the:

A

Potential for pressure-induced back drafting in the house

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38
Q

(T/F) If the relative humidity of a room in increased, the air temperature in the room must be increased to maintain the same level of comfort.

A

False

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39
Q

A proper heat loss calculation has been performed for a house which requires a furnace replacement. The numbers indicate the heat loss is 100,000 Btu/h. Which of following furnace should be selected for the installation?

A

A 120,000 Btu/h input furnace with an AFUE rating of 85%

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40
Q

To ensure that negative building pressure never causes pressure-induced backdrafting:

A

Use sealed combustion, direct vent appliances

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41
Q

Air enters the house through a process called _____________.

A

Infiltration

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42
Q

If too many lava rocks are placed in the rack of a barbeque:

A

The burner will burn out prematurely

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43
Q

The required clearance to combustible materials above a pendant gas lamp is:

A

18 inches

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44
Q

What device is used to prove a dryer motor is running?

A

Centrifugal switch

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45
Q

The pressure relief valve on a propane tank is set at:

A

250 psig

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46
Q

The closing force in a gas pressure regulator is the:

A

Pressure downstream of the regulator

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47
Q

A pressure regulator:

A

Controls outlet pressure

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48
Q

To what specifications are propane cylinders, manufactured in Canada after January 1st 1993, built and marked?

A

Transport Canada

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49
Q

A worn or dirty seat on a regulator assembly may produce:

A

High pressure downstream

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50
Q

Propane containers located on the outside of a recreational vehicle shall be:

A

Mounted on the “A” frame as close to the front of the vehicle as practicable

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51
Q

What is purpose of purging new or reconditioned cylinders?

A

To remove water and oxygen

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52
Q

If a second stage regulator is adjusted to compensate to undersized piping, one of the results will be:

A

High lock up pressures

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53
Q

What should be done if it is noticed that a regulator set in a loading dock area is not protected against physical damage?

A

B) Notify the local gas utility that protection is required

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54
Q

A two stage regulation system on propane will:

A

B) Reduce fluctuating delivery pressures

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55
Q

Which regulator component is used as a measuring element?

A

C) The diaphragm

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56
Q

Can a shut-off valve be installed upstream of a relief valve to allow for the removal of the relief valve for servicing without having to empty the contents of the tank?

A

No

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57
Q

What will happen if the adjusting screw of a regulator is turned counter-clockwise, decreasing the spring tension?

A

B) The downstream pressure will decrease

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58
Q

Which of the follow best describes a bellows type meter?

A

One which uses the volume displaced through chambers divided by a flexible material to drive dials

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59
Q

The primary function of a surge arrestor in the top of a regulator is to:

A

Limit the escape of the gas to 1 cu.ft/hour

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60
Q

What is the largest pronto cylinder manufactured?

A

420 pounds WC

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61
Q

Which of the following are used in an absorption refrigeration cycle

A

Ammonia and hydrogen

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62
Q

When a refrigerator develops excessive frost on the evaporator

A

It becomes less efficient

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63
Q

A propane refrigerator runs on:

A

Propane, 12 volts D.C and 24 volts D.C

64
Q

How often should a refrigerator be serviced and cleaned?

A

At least once a year or as recommended by the manufacturer

65
Q

Why does the recommended range of CO2 in a converted furnace differ from the ultimate amount of CO2 of 11.9%?

A

To provide a safety margin

66
Q

How can the location of a leak in heat exchanger to be determined?

A

All of the above

67
Q

What materials are approved for joining single wall vent connectors?

A

C) Sheet metal screw

68
Q

. A found draft burner has a blower that produces sufficient pressure to overcome the resistance of the:

A

B) Burner and the appliance

69
Q

Two undesirable products of incomplete combustion are:

A

Carbon monoxide and aldehydes

70
Q

When it is necessary, where should a vent connector be reduced?

A

At the breeching of the appliance

71
Q

The most likely cause of a puddle of water at the side of a water heater where the drain cock and relief valve are located is that:

A

The relief valve is opening periodically

72
Q

In combustion heating systems employing a water heater and an air handler, the burner is activated by the temperature sensor in the:

A

Room thermostat

73
Q

Temperature Rise”, when applied to a hot water heater is the:
B

A

Water temperature difference across the heater

74
Q

The “stacking effect” in a water heater is usually caused by:

A

Short draws of water from the heater

75
Q

Combination systems are sized to deliver ______________ of the calculated heat loss of the building.

A

120%

76
Q

When determining the position of an air handler and a water heater to be connected for combination heating use, the most important factor to consider from the following is:

A

Venting of the water heater

77
Q

As the outlet temperature decreases from a water heater to the heating loop in a combination heating system, the:

A

Heating output from the air handler decreases

78
Q

. If a water heater has black scorch marks on the front above the burner access opening, what should be done?

A

D) Adjust the burner flame and check the flue baffle for soot or scale

79
Q

Where should the condensate line of condensing furnace terminate?

A

At an open drain

80
Q

There is a no heat call for the system, use the following…
Terminals at the thermostat read 24V
Gas valve coil reads 0V
Gas Coil to gas coil common reads 24V
Points across high limit read 0 volts.
Determine which component is open…

A

Thermostat

81
Q

There is a no heat call for the system. Use the following…
Thermostat terminals reads 0V
Gas valve coil terminals reads 0V
High limit terminals reads 110V
L & N terminals reads 110V
Determine which component is open:

A

Thermostat

82
Q

There is a no heat call for the system, use the following…
Thermostat terminals read 0V
Gas valve coil terminals read 24V
Gas valve (thermostat side) to common terminals read 0V
Gas valve (transformer side) to common terminals read 24V
Determine which component is open:

A

C) High limit

83
Q

A furnace is found to be cycling on the high limit. The fan rotation, belt, and the clock input is according to the rating late. What is the most likely problem?

A

Return air volume too low

84
Q

The high temperature limit switch in the circuitry if a conventional residential furnace is wired in series with the:

A

Gas valve

85
Q

When does an electrically operated automatic vent damper open on mid-efficiency furnace?

A

Before the ignition cycle

86
Q

A low water cut off is required on a steam boiler not under continuous attendance by certified operator, when the rated input is:

A

Any value

87
Q

Automatic chlorinators must be installed:

A

Downstream of the heater

88
Q

The external bypass valve is set by:

A

D) Determining the temperature rise across the appliance

89
Q

Scenario: There is a storage type of system. The boiler is hot, the circulating motor is running and the thermostat is called for heat and the upstairs is cold. Most likely the problem is:

A

D) A broken pump coupling

90
Q

If it has been determined that a steam boiler is on and the water gauge indicates no water, what should be done immediately?

A

A) Shut off the fuel supply

91
Q

A fire tube boiler has:

A

Water outside the tubes and flue gasses inside

92
Q

If the bypass valve on a pool heater is closed:

A

) The flue gasses may condense

93
Q

Why is a pressure relief valve installed on a pool heater system?

A

To prevent damage to the system

94
Q

What type of room heater may be installed in a bathroom?

A

Direct vent

95
Q

Dirt pockets are required on:

A

D) None of the above

96
Q

Which of the following is acceptable when a fireplace insert is installed?

A

A) A metal chimney liner

97
Q

When can a certified hose be used to connect a construction heater to temporary piping?

A

D) Only when a lever handle shut off valve is installed upstream of the hose

98
Q

What type of vent must be used when the vent of a wall furnace will be concealed in a partition wall?

A

D) BW vent

99
Q

A room heater installed in either a sleeping area or public area shall be:

A

Equipped with a regulator

100
Q

What must be done during the installation of a “gas log” fireplace?

A

Secure the chimney damper in the open position

101
Q

What must be ensured before electronic cells are removed for cleaning?

A

C) Cells must be de-energized and discharged

102
Q

What is the approximate secondary voltage range of an electronic air cleaner?

A

D) 9000 - 12000 volts

103
Q

What happens to the system in the heating mode if the pre-filter in an electronic air cleaner gets plugged with dirt?

A

B) The burner shuts off on high limit

104
Q

Plate humidifiers operate:

A

A) All the time the fan is running

105
Q

What is the purpose of an electronic air cleaner?

A

D) To remove dust, smoke, and odours from the air

106
Q

What will happen in a furnace if the cooling coil gets too dirty>

A

D) The supply air flow will decrease

107
Q

How are electronic air cleaners wired?

A

A) In parallel with the fan motor

108
Q

The primary voltage for duct mounted electronic air cleaners is:

A

B) 120 - 130 volts

109
Q

How many duct opening are required for a bypass humidifier?

A

B) Two

110
Q

In a domestic air conditioning applications, what is the minimum volume of supply air per ton of cooling required?

A

C) 400

111
Q

A combination fan-limit control:

A

D) Controls the blower operation and shuts the burner off on over temperature

112
Q

Convection is:

A

B) Heat transfer through fluids

113
Q

What would the blow speed be if the motor pulley is twice the diameter of the blower pulley?

A

D) 2 times the motor speed

114
Q

If the fan compartment door of an appliance if left off, the motor:

A

D) Current will increase

115
Q

In order to prevent condensation from forming on the outside of the a duct, the duct must be

A

Insulated on the outside

116
Q

Heat which when added to or removed from a substance causes a change of temperature is called:

A

D) Sensible heat

117
Q

Air filtration devices are generally located in the:

A

C) Return air plenum

118
Q

An adjustable sheave pulleys the most commonly used on a:

A

A) Motor shaft

119
Q

Which of the following must be considered when sizing a branch circuit fuse?

A

A17: the gauge of the wire

120
Q

The incoming power supply to residential home is:

A

A18: 240/1/60

121
Q

As the length of an electrical run increases, it may be necessary to:

A

A19: increase the wire size

122
Q

when using an ohmmeter, the most important thing to remember is to:

A

A20: De-energize the circuit

123
Q

Flame rods (flame rectifiers) utilize:

A

Milliamps

124
Q

A combination gas valve contains a(n):

A

A38: manual shut off valve, an automatic gas valve, a pressure regulator

125
Q

When using a jumper wire to by-pass the thermostat at the gas valve, why should you always disconnect at least on lead of the thermostat

A

A39: if incorrectly attached, it may burn out the heat anticipator in the thermostat

126
Q

which of the following is used in high temperature sensing control elements?

A

A40: mercury

127
Q

how many volts are required to property operate a hot surface igniter?

A

A42: 115-125 vac

128
Q

Which device shuts off the spark igniter in a spark ignition dryer after ignition?

A

A62: ignition sensor

129
Q

: if the regulator vent became blocked with the regulator in the open position

A

A63: there would be excessive downstream gas pressure

130
Q

A two-stage regulation system in propane will:

A

A64: reduce fluctuating delivery pressures

131
Q

excessive gas pressure on the downstream side of a lock-up type pressure regulator can be caused by”

A

A65: a blocked vent line

132
Q

temperature compensated meters are installed to:

A

A66: provide accurate measurement in varying weather conditions

133
Q

(T/F) the primary function of a surge arrestor in the top of a regulator is to reduce the opening speed of the regulator.

A

A68: true

134
Q

Which item is used as a regulator’s resticing element?

A

A69: the regulator valve

135
Q

what is the largest propane cylinder manufactured?

A

A70: 1000lb

136
Q

78: A relief valve on regulator operates when:

A

A78: there is excessive pressure in the supply pipping

137
Q

Pressure regulator on construction heatyerts shall be set to limit the outlet pressure to:

A

A79: the design operating pressure of the heater

138
Q

What is the best method of adjusting and setting the pressure on an appliance regulator

A

A80: adjust the regulator set point using a manometer to the appliance rating

139
Q

When the .01 cubic meter dial of a natural gas meter indicates movement this means

A

A81: a leak is present

140
Q

how often should a refrigerator be serviced and cleaned?

A

A83: at least once a year or as recommended by the manufacture

141
Q

Q84:a three way refrigerator runs on:

A

A84: propane, 12 volts d.c. and 120 volts a.c.

142
Q

what kind of propane refrigerator can be installed in a recreational vehicle?

A

A85: an approved direct vent type or equivalent

143
Q

(T/F) : a generator, evaporator, absorber and condenser are the main components of a gas-fired refrigerator

A

A86: true

144
Q

A fan assist burner is designed to

A

overcome the resistance of the burner only

145
Q

The person responsible for sizing the burner for a retrofit furnace is the:

A

A89: Installer

146
Q

what action should a technician take if a cracked heat exchanger is found in a conventional style furnace?

A

A112: inform the customer, shut off the gas supply, and inform the fuel supplier

147
Q

when retrofitting a heating system, a new high efficiency furnas shall be sized according to the:

A

A113: heat loss of the residence

148
Q

A furnace is found to be cycling on high limit. The fan rotation, belt, filter and the clocks input is according to the rating plate. What is the most likely problem.

A

A114:the thermostat heat anticipator is set to high or the return air volume is to low

149
Q

A customer complains of an unusual noise from the furnace. There is a 24 volt solenoid gas valve working properly, but humming. From the following list, what is the most probable cause?

A

A115: Low voltage

150
Q

When an indoor gas-fired pool heater is being replaced, the new finned tuble heater shall be

A

A122: direct vent type

151
Q

:A pressure reducing valve:

A

A125: reduces the city main pressure to a safe working pressure

152
Q

which device can be used to determine air restriction in a duct system?

A

A157: manometer

153
Q

which of the following two measurements are required to determined the relative humidity

A

A160: dry bulb and wet bulb

154
Q

convection is:

A

heat transfer through fluids.

155
Q

If fresh air is fan controlled and used for combustion air, it must be intertocked with thes ?

A

gas valve.

156
Q

If the belt on a blower is too tight. the motor:

A

current will increase.

157
Q

What is the blower speed if the motor pulley is twice the diameter of the blower pulley?

A

2 times the motor speed

G2 (1 decks)

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