313 4th attempt

313 4th attempt
124問 • 1年前
  • Modder One
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    問題一覧

  • 1

    Heat, which is added to a vapor after the change of state occurs, is called

    superheat

  • 2

    The value of C.O.P in vapour compression cycle is usually

    always more than unity

  • 3

    . The contact points on an energized heater relay are being checked by a technician using a volt meter. If a small voltage is detected across the contacts, this would be an indication of

    pitted contact

  • 4

    What is equivalent to one PSI?

    27.7" WC

  • 5

    Thermocouple extension wire may be readily distinguished from regular thermocouple- grade wire by which of the following?

    outer sheath colour

  • 6

    A technician takes the temperature rise of an electric furnace. What is being measured?

    sensible heat only

  • 7

    What is the term used to describe the input side of a transformer?

    primary side

  • 8

    What effect does the fan have on the air?

    it heats it

  • 9

    The pressure at the inlet of a refrigerant compressor is called

    suction pressure

  • 10

    For air conditioning the operation theater in a hospital, the percentage of outside air in the air supplied is

    100

  • 11

    The superheated vapour region, in a pressure enthalpy chart, is represented by the space

    Between the saturated liquid line and saturated vapour line

  • 12

    A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be

    4 kw

  • 13

    A refrigerant release heat when

    it condenses

  • 14

    In vapour compression cycle, the condition of refrigerant is high pressure saturated liquid

    Before entering the expansion valve

  • 15

    Turbines run most efficiently at?

    high speed

  • 16

    What does a refrigeration system do with the heat in the refrigerated area?

    t moves the heat from the refrigerated area to another area.

  • 17

    Which of the following statement is correct?

    all of the above

  • 18

    What is blower door test equipment used for?

    A testing apparatus used for measuring building envelope air tightness.

  • 19

    When the air flow into a duct is reduced, what happens to the pressure drop across the filter?

    it decreases

  • 20

    Insulating the water heater and hot water piping is _________.

    one of the easiest ways to make an immediate impact on energy savings.

  • 21

    Category IV furnaces _______________.

    create positive pressure conveying flue gases to the outside

  • 22

    Freon group of refrigerants are

    Nontoxic and non-inflammable

  • 23

    Galvanize is made from?

    zinc

  • 24

    Latent heat is measured in:

    British Thermal Unit

  • 25

    Heat which causes a change in temperature of a substance is called

    Sensible heat

  • 26

    If a TEV sensing bulb has lost all of its charge, what effect would this have on the air conditioning system?

    It would cause the low side pressure to decrease.

  • 27

    If a system using a TXV has a suction of 3/4" diameter, where should the sensing bulb be placed?

    At the 12 o'clock position

  • 28

    A key element of a comprehensive safety and health program is one of the following?

    Hazard prevention and control.

  • 29

    What type of fire extinguisher should be used on electrical fires?

    class C

  • 30

    As a boiler deteriorates the safety factor?

    goes down

  • 31

    The relative coefficient of performance is equal to

    (Actual C.O.P.) /(Theoretical C.O.P.)

  • 32

    A 60AH 24V battery is supplying a 200W load. How many hours can the battery supply the load

    7.2

  • 33

    The coefficient of performance of Heat Pump is always _________ one.

    greater then

  • 34

    Using a three positions liquid line service valve, when is the back-seated position used?

    When the manifold gauge are disconnected

  • 35

    The type of compressor that allows access to the internal components is the _______.

    reciprocating semi-hermetic

  • 36

    When applying solder to a splice connection, what is the proper procedure you should do?

    The solder is applied to the splice after it has been heated for a few seconds.

  • 37

    An oversized heating and cooling system can cause which of the following?

    Moisture damage to a furnace heat exchanger and inadequate humidity removal during cooling cycles.

  • 38

    Short cycling during pump down can be caused by:

    a leaking compressor suction valve.

  • 39

    The greatest permissible pressure drop allowed would be in the?

    discharge line

  • 40

    To find the correct condenser saturation temperature for a given pressure of 407C, it’s best to use

    A pressure/temperature chart

  • 41

    The automatic expansion valve (AEV) maintains a constant ______ in the evaporator.

    pressure

  • 42

    If discharge pressure/suction pressure/Super heat is low/sub cooling is high what is the symptom

    over charged system

  • 43

    If discharge pressure is low/suction is low/super heat high/subcooling is low/Amps are low what is the symptom

    low on charge

  • 44

    If a heat pump defrost is fastened to the liquid line in the outdoor unit

    defrost will seldom occur

  • 45

    If a heat pump defrost thermostat (spst 27/80F) is jumperef out, bypassed: ("R" to "DFT")

    defrost will always engage when compressor run time elapses and will last the full 10 minutes

  • 46

    For residential air conditioning, one of the installed refrigerant lines is insulated

    primarily to prevent the excess absorption of super heat

  • 47

    In a series circuit the current

    is the same throughout the series path

  • 48

    Which of the following compressor oil types is generally considered the most compatible with hfc refrigerants

    POE

  • 49

    An oil separator must be mounted

    above the compressor crankcase

  • 50

    A rotating vein anometer measures

    FPM

  • 51

    The air you are breathing is

    superheated

  • 52

    Which of the following is the correct sequence of work

    recover the refrigerant, evacuate the system, replace the filter core, recharge the system

  • 53

    What does subcooling refer to in the refrigeration system

    the reduction of refrigerant temperature below the saturation point

  • 54

    The three methods of heat transfers are

    conduction, convection, and radiation

  • 55

    Which of the following is not a type of compressor

    lateral

  • 56

    A lockout relay can be reset by

    all of the above

  • 57

    A manifold gauge set is properly attached to the suction and discharge valves on a compressor in order to read the high and low side pressures of the system what position should the manifold valves be in?

    mid-seated

  • 58

    The condenser gives up

    sensible in Latent heat

  • 59

    5 lb of water is heated by 2° f how many BTUs were added to the water

    10 BTUs

  • 60

    Which type of copper tubing has the thickest wall

    type k

  • 61

    The total minimum open area for air to flow through on a supply Air register is called

    free area

  • 62

    Which of the following is not a type of expansion device

    centrifugal expansion valve

  • 63

    AR 22 air conditioning system is operating with a head pressure of 220 PSIG in the suction pressure of 68.5 PST. The temperature measurement to taken on the suction line 8 in from the suction service valve reads 60°. The temperature measurement taken on the liquid line leaving the condenser 90° fahrenheit. What is the low side superheat

    20° of superheats

  • 64

    The service technician measures a return air temperature of a degrees and a supply air temperature 55°? What if anything maybe wrong with this residential split system air conditioning unit

    low on evaporator airflow

  • 65

    A half-filled cylinder of refrigerant at 80° f will be

    saturated

  • 66

    Case coil should be mounted to furnace cabinets with

    duct tape

  • 67

    The higher the Merv writing of a filter dryer the?

    smaller the particulates the filters can entrap

  • 68

    On a psychometric chart what does the vertical axis typically represent

    dry bulb temperature

  • 69

    To change Fahrenheit to Celsius which formula is used?

    C = (F - 32) ÷ 1.8

  • 70

    0 lb gauge corresponds on absolute scale 2

    14.7

  • 71

    The position of the valve stem on the suction server valve is normally

    fully backseated

  • 72

    The discharge line temperature of a reciprocating compressor should never be allowed to exceed how many degrees

    325 degrees

  • 73

    Vacuum pressure is measured in

    both inches of mercury in microns

  • 74

    During the defrost cycle of a heat pump the very heat is used to

    provide supplementing heating indoors

  • 75

    The normal compression ratio of a typical comfort Air conditioning application should be in the range of

    2 to 3

  • 76

    Which of the following is not a type of condenser

    absorptive

  • 77

    A thermostatic expansion valve controls

    evaporator superheat

  • 78

    A double suction riser is used to

    improve oil return as system capacity changes

  • 79

    A hot liquid line with low to normal high side pressure is an indication of

    a undercharge system

  • 80

    A technician is evacuating the system and knows the pressure drop decreasing this could indicate

    there is a leak or moisture remaining in the system

  • 81

    The amount of heat required to melt 1 lb of ice at 32° f

    180 BTUs

  • 82

    A grill equipped with a damper control is called

    a register

  • 83

    Which service valve should never be front seated while the compressor is operating

    compressor discharge service valve

  • 84

    Which type of compressor can be disassembled for repairs in the field

    semi hermetic compressor

  • 85

    The factor determining the correct quantity of air for each room in a building is

    calculate the heat load for each room

  • 86

    Why is it necessary to remove moisture from an HVAC system during evacuation

    to prevent ice formation inside the system

  • 87

    A customer's compressor has failed and they wish to replace the outer unit only to properly replace the unit it must be size to match

    the capacity of the evaporator

  • 88

    As the pressure over a liquid is lowered

    the boiling point of liquid decreases

  • 89

    High subcooling in a refrigerator system might indicate

    High evaporator air flow

  • 90

    On a residential AC units with a reciprocating compressor without any hard start kits or time to lay timers which of the following is true

    the pressures must be nearly equalized before the compressor can start

  • 91

    And oversized suction line could cause

    poor oil return to the compressor

  • 92

    Which is most likely application for a capacitor start capacitor one motor

    in an air conditioner

  • 93

    A 3 ampere low voltage fuse in a unit is found bypassed, the technician should

    investigate why the fuse was bypassed and repair

  • 94

    The primary reason for nitrogen sweeping while brazing is

    to displace oxygen from inside the joint being braised

  • 95

    Which of the following would occur if you could change the wiring for the high limit switch with the wiring for the fan switch on a furnace

    the fan will can run continuously the burner will not ignite

  • 96

    A compressor's purpose in the refrigeration cycle is to

    Raise the refrigerant's pressure and temperature

  • 97

    When using a three-position liquid line service valve, the back-seated position is intended for:

    Pumping down the system

  • 98

    Two basic methods for refrigerant removal from a system are:

    Active and passive

  • 99

    In an HVAC system, a duct system with significant leaks can result in

    Increased energy consumption and reduced efficiency

  • 100

    PLC stands for

    Programmable Logic Controller

  • 313d

    313d

    Modder One · 230問 · 1年前

    313d

    313d

    230問 • 1年前
    Modder One

    問題一覧

  • 1

    Heat, which is added to a vapor after the change of state occurs, is called

    superheat

  • 2

    The value of C.O.P in vapour compression cycle is usually

    always more than unity

  • 3

    . The contact points on an energized heater relay are being checked by a technician using a volt meter. If a small voltage is detected across the contacts, this would be an indication of

    pitted contact

  • 4

    What is equivalent to one PSI?

    27.7" WC

  • 5

    Thermocouple extension wire may be readily distinguished from regular thermocouple- grade wire by which of the following?

    outer sheath colour

  • 6

    A technician takes the temperature rise of an electric furnace. What is being measured?

    sensible heat only

  • 7

    What is the term used to describe the input side of a transformer?

    primary side

  • 8

    What effect does the fan have on the air?

    it heats it

  • 9

    The pressure at the inlet of a refrigerant compressor is called

    suction pressure

  • 10

    For air conditioning the operation theater in a hospital, the percentage of outside air in the air supplied is

    100

  • 11

    The superheated vapour region, in a pressure enthalpy chart, is represented by the space

    Between the saturated liquid line and saturated vapour line

  • 12

    A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be

    4 kw

  • 13

    A refrigerant release heat when

    it condenses

  • 14

    In vapour compression cycle, the condition of refrigerant is high pressure saturated liquid

    Before entering the expansion valve

  • 15

    Turbines run most efficiently at?

    high speed

  • 16

    What does a refrigeration system do with the heat in the refrigerated area?

    t moves the heat from the refrigerated area to another area.

  • 17

    Which of the following statement is correct?

    all of the above

  • 18

    What is blower door test equipment used for?

    A testing apparatus used for measuring building envelope air tightness.

  • 19

    When the air flow into a duct is reduced, what happens to the pressure drop across the filter?

    it decreases

  • 20

    Insulating the water heater and hot water piping is _________.

    one of the easiest ways to make an immediate impact on energy savings.

  • 21

    Category IV furnaces _______________.

    create positive pressure conveying flue gases to the outside

  • 22

    Freon group of refrigerants are

    Nontoxic and non-inflammable

  • 23

    Galvanize is made from?

    zinc

  • 24

    Latent heat is measured in:

    British Thermal Unit

  • 25

    Heat which causes a change in temperature of a substance is called

    Sensible heat

  • 26

    If a TEV sensing bulb has lost all of its charge, what effect would this have on the air conditioning system?

    It would cause the low side pressure to decrease.

  • 27

    If a system using a TXV has a suction of 3/4" diameter, where should the sensing bulb be placed?

    At the 12 o'clock position

  • 28

    A key element of a comprehensive safety and health program is one of the following?

    Hazard prevention and control.

  • 29

    What type of fire extinguisher should be used on electrical fires?

    class C

  • 30

    As a boiler deteriorates the safety factor?

    goes down

  • 31

    The relative coefficient of performance is equal to

    (Actual C.O.P.) /(Theoretical C.O.P.)

  • 32

    A 60AH 24V battery is supplying a 200W load. How many hours can the battery supply the load

    7.2

  • 33

    The coefficient of performance of Heat Pump is always _________ one.

    greater then

  • 34

    Using a three positions liquid line service valve, when is the back-seated position used?

    When the manifold gauge are disconnected

  • 35

    The type of compressor that allows access to the internal components is the _______.

    reciprocating semi-hermetic

  • 36

    When applying solder to a splice connection, what is the proper procedure you should do?

    The solder is applied to the splice after it has been heated for a few seconds.

  • 37

    An oversized heating and cooling system can cause which of the following?

    Moisture damage to a furnace heat exchanger and inadequate humidity removal during cooling cycles.

  • 38

    Short cycling during pump down can be caused by:

    a leaking compressor suction valve.

  • 39

    The greatest permissible pressure drop allowed would be in the?

    discharge line

  • 40

    To find the correct condenser saturation temperature for a given pressure of 407C, it’s best to use

    A pressure/temperature chart

  • 41

    The automatic expansion valve (AEV) maintains a constant ______ in the evaporator.

    pressure

  • 42

    If discharge pressure/suction pressure/Super heat is low/sub cooling is high what is the symptom

    over charged system

  • 43

    If discharge pressure is low/suction is low/super heat high/subcooling is low/Amps are low what is the symptom

    low on charge

  • 44

    If a heat pump defrost is fastened to the liquid line in the outdoor unit

    defrost will seldom occur

  • 45

    If a heat pump defrost thermostat (spst 27/80F) is jumperef out, bypassed: ("R" to "DFT")

    defrost will always engage when compressor run time elapses and will last the full 10 minutes

  • 46

    For residential air conditioning, one of the installed refrigerant lines is insulated

    primarily to prevent the excess absorption of super heat

  • 47

    In a series circuit the current

    is the same throughout the series path

  • 48

    Which of the following compressor oil types is generally considered the most compatible with hfc refrigerants

    POE

  • 49

    An oil separator must be mounted

    above the compressor crankcase

  • 50

    A rotating vein anometer measures

    FPM

  • 51

    The air you are breathing is

    superheated

  • 52

    Which of the following is the correct sequence of work

    recover the refrigerant, evacuate the system, replace the filter core, recharge the system

  • 53

    What does subcooling refer to in the refrigeration system

    the reduction of refrigerant temperature below the saturation point

  • 54

    The three methods of heat transfers are

    conduction, convection, and radiation

  • 55

    Which of the following is not a type of compressor

    lateral

  • 56

    A lockout relay can be reset by

    all of the above

  • 57

    A manifold gauge set is properly attached to the suction and discharge valves on a compressor in order to read the high and low side pressures of the system what position should the manifold valves be in?

    mid-seated

  • 58

    The condenser gives up

    sensible in Latent heat

  • 59

    5 lb of water is heated by 2° f how many BTUs were added to the water

    10 BTUs

  • 60

    Which type of copper tubing has the thickest wall

    type k

  • 61

    The total minimum open area for air to flow through on a supply Air register is called

    free area

  • 62

    Which of the following is not a type of expansion device

    centrifugal expansion valve

  • 63

    AR 22 air conditioning system is operating with a head pressure of 220 PSIG in the suction pressure of 68.5 PST. The temperature measurement to taken on the suction line 8 in from the suction service valve reads 60°. The temperature measurement taken on the liquid line leaving the condenser 90° fahrenheit. What is the low side superheat

    20° of superheats

  • 64

    The service technician measures a return air temperature of a degrees and a supply air temperature 55°? What if anything maybe wrong with this residential split system air conditioning unit

    low on evaporator airflow

  • 65

    A half-filled cylinder of refrigerant at 80° f will be

    saturated

  • 66

    Case coil should be mounted to furnace cabinets with

    duct tape

  • 67

    The higher the Merv writing of a filter dryer the?

    smaller the particulates the filters can entrap

  • 68

    On a psychometric chart what does the vertical axis typically represent

    dry bulb temperature

  • 69

    To change Fahrenheit to Celsius which formula is used?

    C = (F - 32) ÷ 1.8

  • 70

    0 lb gauge corresponds on absolute scale 2

    14.7

  • 71

    The position of the valve stem on the suction server valve is normally

    fully backseated

  • 72

    The discharge line temperature of a reciprocating compressor should never be allowed to exceed how many degrees

    325 degrees

  • 73

    Vacuum pressure is measured in

    both inches of mercury in microns

  • 74

    During the defrost cycle of a heat pump the very heat is used to

    provide supplementing heating indoors

  • 75

    The normal compression ratio of a typical comfort Air conditioning application should be in the range of

    2 to 3

  • 76

    Which of the following is not a type of condenser

    absorptive

  • 77

    A thermostatic expansion valve controls

    evaporator superheat

  • 78

    A double suction riser is used to

    improve oil return as system capacity changes

  • 79

    A hot liquid line with low to normal high side pressure is an indication of

    a undercharge system

  • 80

    A technician is evacuating the system and knows the pressure drop decreasing this could indicate

    there is a leak or moisture remaining in the system

  • 81

    The amount of heat required to melt 1 lb of ice at 32° f

    180 BTUs

  • 82

    A grill equipped with a damper control is called

    a register

  • 83

    Which service valve should never be front seated while the compressor is operating

    compressor discharge service valve

  • 84

    Which type of compressor can be disassembled for repairs in the field

    semi hermetic compressor

  • 85

    The factor determining the correct quantity of air for each room in a building is

    calculate the heat load for each room

  • 86

    Why is it necessary to remove moisture from an HVAC system during evacuation

    to prevent ice formation inside the system

  • 87

    A customer's compressor has failed and they wish to replace the outer unit only to properly replace the unit it must be size to match

    the capacity of the evaporator

  • 88

    As the pressure over a liquid is lowered

    the boiling point of liquid decreases

  • 89

    High subcooling in a refrigerator system might indicate

    High evaporator air flow

  • 90

    On a residential AC units with a reciprocating compressor without any hard start kits or time to lay timers which of the following is true

    the pressures must be nearly equalized before the compressor can start

  • 91

    And oversized suction line could cause

    poor oil return to the compressor

  • 92

    Which is most likely application for a capacitor start capacitor one motor

    in an air conditioner

  • 93

    A 3 ampere low voltage fuse in a unit is found bypassed, the technician should

    investigate why the fuse was bypassed and repair

  • 94

    The primary reason for nitrogen sweeping while brazing is

    to displace oxygen from inside the joint being braised

  • 95

    Which of the following would occur if you could change the wiring for the high limit switch with the wiring for the fan switch on a furnace

    the fan will can run continuously the burner will not ignite

  • 96

    A compressor's purpose in the refrigeration cycle is to

    Raise the refrigerant's pressure and temperature

  • 97

    When using a three-position liquid line service valve, the back-seated position is intended for:

    Pumping down the system

  • 98

    Two basic methods for refrigerant removal from a system are:

    Active and passive

  • 99

    In an HVAC system, a duct system with significant leaks can result in

    Increased energy consumption and reduced efficiency

  • 100

    PLC stands for

    Programmable Logic Controller