Gas Install Chpt. 5&6

Question 1

U-tube manometers (water-filled) usually read very low gas pressures and express them in

Answer 1

inch of water column

Question 2

Why would a mercury manometer be used instead of a water manometer?

Answer 2

more compact, read higher pressure

Question 3

Name the parts of the regulator which correspond to the previous question.

Answer 3

(Restrict) Valve seat, orficie, (sensing) diaphragm, (loading) regulator spring test

Question 4

what is the stated advantage of using higher gas piping pressures than that required by the appliance?

Answer 4

smaller pipe

Question 5

turning the adjusting screw clockwise would ______ the regulator outlet pressure

Answer 5

increase

Question 6

what are five factors which must be considered when choosing a gas pressure regulator

Answer 6

1)rate of flow 2)type of gas 3)inlet gas pressure 4)outlet gas pressure 5)size of gas pipe, pipe sizing an inlet and outlet of regulator

Question 7

a diaphragm gas valve uses _______ as the primary force to open or close the valve

Answer 7

gas pressure

Question 8

when the components of a gas valve-train are all contained within one valve, it is known as a _______

Answer 8

combination gas valve

Question 9

if a pilot only comes on when there is a call for heat, it is called a/an ________ pilot

Answer 9

direct ignition

Question 10

when the reset button is pushed, gas flows to both main and pilot burners

Answer 10

false

Question 11

the movement of _______ causes an electrical current to flow in a circuit

Answer 11

electrons

Question 12

the device which uses heat to create electricity is called a _______ or ________

Answer 12

thermocouple, thermopile

Question 13

a spark igniter for a barbecue is an example of what type of electricity

Answer 13

pizo

Question 14

in an AC (alternating current) wave form, both ______ and ______ buildup, peak, reverse direction, then build up and peak in the opposite direction, before returning to zero.

Answer 14

voltage, current

Question 15

where is three-phase electricity used

Answer 15

commercial and industrial applications

Question 16

current generated in north America is at ___ cycles per second, or hertz

Answer 16

60

Question 17

electrical pressure, know as EMF or electromotive force is measured in units called _____

Answer 17

volts

Question 18

electrical resistance is measured in units called ______

Answer 18

ohms

Question 19

what is the most important consideration when using an ohmmeter

Answer 19

power must be off, lock out tag out

100%

Question 20

the term wattage or watts is an expression of electrical ______; watts equals ______ multiplied by ______

Answer 20

power, volts, amps

Question 21

______ circuits have only one path for current to follow; ______ circuits have multiple paths

Answer 21

series, parallel

Question 22

how is the total resistance in a series circuit calculated?

Answer 22

R=E/I total sum added up

Question 23

correct polarity of the test leads must be observed when using an ammeter with DC.

Answer 23

true

Question 24

the moving part within a switch is called a ____; the contact it makes is called a _____.

Answer 24

pull, throw

Question 25

the simplest device used to prevent excessive current from damaging circuits is called a _____

Answer 25

fuse

Question 26

what makes the operation of a circuit breaker from that of a fuse

Answer 26

you can reset a circuit breaker

Question 27

by what electrical processes does a step-up or a step-down transformer operate?

Answer 27

electromagnetic induction

Question 28

what two electrical components are found within a relay

Answer 28

switch, load

Question 29

what is the name of the wiring diagram which shows the electrical components of a gas appliance much like they appear behind the service door of the appliance

Answer 29

schematic

Question 30

what are three advantages of a ladder diagram over a schematic diagram

Answer 30

make it easy to tell which are series and parallel, easier to follow

Question 31

as an overall safety precaution when working around live equipment, always assume that any wire could be ______

Answer 31

live

Question 32

what do automatic gas valves usually employ as an actuator to make them open or close?

Answer 32

electromagnetic coil

Question 33

a low-water cutoff would be classified as a ________ control

Answer 33

safety limit

Question 34

a thermostat would be classified as a/an _______ control

Answer 34

operating

Question 35

if a boiler needs flowing water in order for it to operate, this could be proven electrically by using a ________

Answer 35

flow switch

Question 36

a solenoid gas valve would be an example of a/an _______

Answer 36

actuator

Question 37

most state, local or provincial codes allow a maximum of ______ seconds for a thermocouple and power unit to drop out

Answer 37

90

Question 38

what is the device called which is found within a thermostat, and is used to minimize thermal lag?

Answer 38

anticipator

Question 39

what is th function of a direct-acting aquastat?

Answer 39

opens or breaks contact on rise in temperature

Question 40

on what types of systems are pressuretrols normally found

Answer 40

steam heating system

Question 41

a probe-type low water cutoff uses the _______ of the liquid to complete a circuit

Answer 41

conductivity

Question 42

what is the maximum flame failure response time for a high volume (over 400,000 Btuh) appliance?

Answer 42

10 seconds or less

Question 43

a difference in ______ between the hot and cold junctions of a thermocouple or thermopile will generate electricity

Answer 43

temprature

Question 44

the pilot burner flame must envelope _______ inch(es) of the hot junction of a thermocouple or thermopile

Answer 44

3/8 to 1/2

Question 45

why are photocells not used to monito gas flames?

Answer 45

gas flame does not produce enough visible light

Question 46

the earliest flame-rod systems used a flame's ________ to complete an electrical circuit

Answer 46

conductivity

Question 47

an open circuit test of a thermocouple should produce ______ to _____ millivolts: a closed circuit test should roughly one-half of these voltages

Answer 47

20-30 mv

Question 48

most nuisance shutdowns in millivolt systems are a result of excessive _________ in the circuit

Answer 48

resistance

Question 49

when a flashlight battery goes dead, it is because the ______ has been used up

Answer 49

zinc

Question 50

_______ corrode: cathodes do not

Answer 50

anodes

Question 51

one method of preventing underground steel piping from corrosion is to install a/an ________ onto the pipe

Answer 51

sacrificial anode

Question 52

an audible and visual electronic test to find flaws in a coated pipe is termed a _____ test

Answer 52

jeep

Question 53

cathodic protection of underground piping should be supervised by specialist familiar with that type of work.

Answer 53

true

Question 54

name the two different types of domestic hot water heaters, and give a brief description of each type.

Answer 54

instantaneous, storage type

Question 55

what device in the tank of a domestic hot water heater ensures that cold water entering the tank does not immediately leave through the hot outlet?

Answer 55

dip tube

Question 56

the _______ slows the flue gases as they pass upward through the heater, increasing heat transfer and efficiency

Answer 56

flu baffle

Question 57

the specific gravity (relative density) of propane and gasoline vapors is _____ than air

Answer 57

heavier

Question 58

the air passages through a gravity furnace must be _______ than those of a forced air model

Answer 58

larger

Question 59

forced air furnaces use a ______ to move the heated air to the rooms

Answer 59

blower

Question 60

the three types of furnaces, as classified by the direction of air flow across the heat exchanger, are _______, ______ and _______

Answer 60

up flow, down flow, and horizontal

Question 61

how is the combustion efficiency usually determined?

Answer 61

by analyzing componet percentages at the flu gas

Question 62

a ______ boiler combustion control reacts to temperature; the _____ boiler combustion control reacts to pressure

Answer 62

hot water, steam

Question 63

which type of boiler can be assembled in place, and added to if necessary?

Answer 63

cast iron sectional

Question 64

what are the materials from which most hot water boilers are constructed?

Answer 64

steel or cast iron

Question 65

usually, small water volume (low mass) boilers require the ________ to operate before allowing the burner to fire

Answer 65

circulating pump

Question 66

pressure relief valves for residential and small commercial boilers are usually preset at ___ psig (____kPa)

Answer 66

30 psig

Question 67

where might a journey worker find a start-up instructions for a new boiler?

Answer 67

installation manual

Question 68

what type of valve on a gas range allows the use of either propane or natural gas?

Answer 68

universal orifice

Question 69

what is the maximum cooking time for an oven when set to timer mode?

Answer 69

20

Question 70

what do soft yellow flames at the top burner indicate

Answer 70

to fuel rich

Question 71

what is another name for a glo-plug which is used to ight a gas oven burner electrically?

Answer 71

carborundun

Question 72

an oriental range uses a _____ as the cooking bowl (pot)

Answer 72

wok

Question 73

what type of heat is used with broilers?

Answer 73

radiant

Question 74

why are commercial kitchens kept at a slightly negative air pressure

Answer 74

air moves from the dinning room prevent odors

Question 75

to get even more water out of the clothes (after washing and before drying) commercial laundries often use a high-speed spin appliance called a/an ______

Answer 75

extractor

Question 76

what is the maximum time a dryer will spark to try to establish a flame?

Answer 76

10 seconds

Question 77

how many Btuh is equal to q candle power?

Answer 77

65 Btuh