Quiz 3 Prep

Question 1

automatic reset

Answer 1

a switch that opens or closes in response to a change in temperature, pressure, or liquid level

Question 2

manual reset

Answer 2

opens in response to temperature, pressure or liquid level and must be manually reset

Question 3

electromechanical controls

Answer 3

don’t need V to operate and can switch its rated V or less

Question 4

electronic controls

Answer 4

need electricity and specific V to operate

Question 5

direct acting

Answer 5

a switch that OPENS on a rise or increase in temperature, pressure or liquid level

Question 6

reverses acting

Answer 6

a switch that CLOSES on a rise or increase in temperature, pressure or liquid level

Question 7

cut-out switch

Answer 7

a switch that opens to protect the system from short cycling

Question 8

Differential

Answer 8

When a control switch opens b/c it’s set point is exceeded (ex: 200°F) the control will not close again until the Differential is reached (ex: 190°F) the differential is 10°F

Question 9

purpose of a thermostat

Answer 9

to maintain a constant room air temperature

Question 10

thermostat is a what kind of switch

Answer 10

a normally open and direct acting switch with automatic reset

Question 11

nicad batteries do what in a thermostat?

Answer 11

charges while switch is open and uses its 24V when switch is closed

Question 12

purpose of a primary control

Answer 12

to turn off the burner motor, ignition transformer, and oil valve if and when the flame fails

Question 13

stack mounted primary responds to what?

Answer 13

heat of flue gases

Question 14

flue gases should be between what temperatures?

Answer 14

300 and 900°F

Question 15

cad cell primary responds to ?

Answer 15

yellow and orange light

Question 16

cad cell in the dark needs a min of

Answer 16

50,000 ohms

Question 17

a good flame is between ? ohms

Answer 17

300 and 800 ohms

Question 18

trial for ignition for stack mounted primary

Answer 18

either 120, 90, or 60 sec (90 most common)

Question 19

electronic cad cell trial for ignition

Answer 19

15, 30, or 45 sec (15 most common)

Question 20

electromechanical cad cell trial for ignition

Answer 20

15, 30, 45 (45 most common)

Question 21

intermittent ignition

Answer 21

ignition transformer is energized for full running cycle of burner

Question 22

interrupted ignition

Answer 22

ignition transformer is de-energized w/in 1 minute of flame detection

Question 23

Stack Mounted Primary (Intermittent)

Answer 23

Question 24

Stack Mounted Primary (Interrupted)

Answer 24

Question 25

Electromechanical Cad Cell Primary

(Intermittent)

Answer 25

Question 26

Electromechanical Cad Cell Primary

(Interrupted)

Answer 26

Question 27

Where’s the Problem

hot → neutral 120v

Answer 27

load (motor)

Question 28

Where is the Problem

Hot → neutral 0v

Answer 28

line (wires)

Question 29

Which Wire is Incomplete

Hot → Ground 120v problem is?

Answer 29

broken neutral

Question 30

Which Wire is Incomplete

Hot → ground 0v

Answer 30

Broken Hot

Question 31

what is the purpose of a high limit switch?

Answer 31

To protect the unit from damage from two high temperature or pressure

Question 32

define normally closed

Answer 32

a switch that is normally closed when the system is at rest

Question 33

voltage

Answer 33

a difference in electrical pressure measured in V

Question 34

resistance

Answer 34

opposition to flow of electricity

Question 35

amps

Answer 35

amount or volume of electricity

Question 36

hot wire

Answer 36

difference in electrical pressure when compared to neutral or ground

Question 37

ground

Answer 37

connects to the earth

Question 38

neutral wire

Answer 38

has no difference in electrical pressure when compared to ground

Question 39

every circuit must contain

Answer 39

source, switch, and load and must return to source