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313d

AC prep questions

313d
230問 • 1年前AC prep questions
  • Modder One
    • 通報

    問題一覧

  • 1

    The amount of latent heat required to change 1 lb of water to 1 lb of steam

    970 btu

  • 2

    The amount of latent heat required to change one pound of water to 1 lb of ice

    144 btu

  • 3

    Which method of charging should be used when working on an air conditioning system utilizing a TX valve

    Sub cooling method

  • 4

    Which method of charging should be used when working on an air conditioning system utilizing a fixed orifice

    super heat method

  • 5

    A heat pump with a reversing valve that is leaking internally will cause

    high suction pressure and low discharge pressure

  • 6

    If a new air conditioning system is installed with a 45-ft line set and the unit is pre-charged with a refrigerant for a 15-ft line set in the insulation instructions indicate to add 6 oz for each additional foot of line set to correctly charge the equipment the technician would

    at 18 Oz (1 lb 2 oz) of refrigerant

  • 7

    The most common type of compressor found in a residential air conditioning is

    permanent split capacitor

  • 8

    The type of soft copper used in residential air conditioning system is

    type L

  • 9

    The capacitor on a capacitor start induction run compressor is

    in series with the start winding

  • 10

    The vacuum pump is used too

    remove oxygen and moisture from the air conditioning system

  • 11

    A clogged furnace air filter will cause

    low suction line pressure

  • 12

    Which revision listed below will not deplete the ozone layer

    R410A

  • 13

    HFC refrigerant do not contain

    Chlorine

  • 14

    When the line set on an installed air conditioning system is longer than 50 ft and length the technician should

    refer to the insulation instructions

  • 15

    The term LRA stands for

    locked rotor amperage

  • 16

    The electrical supply to residential gas furnace is

    120v, 1 phase, 60 Hz

  • 17

    The contacts on a potential relay are?

    normally closed

  • 18

    Cooling anticipators are resistors in the thermostat that

    provide a false heat load in the off-cycle of the air conditioning system

  • 19

    The minimum CFM required across an evaporator in an air conditioning system

    350 CFM

  • 20

    If an air conditioning system is not functioning in your call to a service equipment the following parameters are found 1. Compressor not operating 2. condenser fan not operating 3. 24 volts found across the contactor coil 4. 240 volts found on the line side of the contactor 5. 120 volts found across contacts 6. 1.2ohms reading across condenser fan motor windings 7. 1.5ohms reading across compressor R & C windings, 3ohms S and R compressor S and C windings and 4.5ohms across S and R windings 8. Compressor capacitor reads 33uf (35 is normal) 9. Condenser fan capacitor reads 4.8uf (5 is normal) What is the problem?

    the contactor is defective

  • 21

    If an air conditioning system is not functioning in your call to the service the equipment the following parameters are found X. Compressor not operating XI. Condenser fan operating XII. 24 volts found across contactor coil XIII. 240 volts found on the line side of the contactor XIV. 0 volts found across contactors contacts XV. 1.2ohms reading across condenser fan motor windings XVI. Infinity ohms reading a cross compressor RNC windings, Infinity readig across S & C windings, 4.5ohms reading across S&R compressor windings XVII. Compressor capacitor reads 33ohms (35 is normal) XVIII. Condenser fan capacitor reads 4.8 ohms (5 is normal)

    the compressor has thermal overload

  • 22

    If an air conditioning system is not functioning in your your call to a service equipment the following parameters are found 1. Compressor not operating 2. Condenser fan operating 3. 24 volts found across contact coil 4. 240 volts found on the line side of the contactor 5. 0 volts found a cross contactor contacts 6. 1.2ohms reading across condenser fan motor windings 7. 1.5ohms reading across compressor R & C windings, 3.0ohms reading across compressor S & C windings, 4.5ohms reading across S & R windings 8. Compressor capacitor reads OL (35uF is normal) 9. Condenser fan capacitor reading 4.8uF (5uF is normal)

    the compressor capacitor is defective

  • 23

    Relays are not available in what?

    triple throw models

  • 24

    On a combination fan and limit control the three tabs represent looking from left to right on the control

    fan off, fan on, high limit

  • 25

    The w terminal on the board of a furnace is used to

    enable the gas valve

  • 26

    Which of the following terms best describes recovery

    take refrigerant out of the air conditioning unit and place it in an approved container

  • 27

    Which of the following terms best describes recycle

    take refrigerant out of the air conditioning unit and place it and approved container put the refrigerant through an on-site oil separation distillation process and return the refrigerant to the system once prepared

  • 28

    Hcfc refrigerants will not be available after

    in January 1st 2030

  • 29

    CFC refrigerants will not be available after

    CFC refrigerants are already banned

  • 30

    Which of the following terms best describe reclaim

    take refrigerant out of the air conditioning unit and place it in approved container send refrigerant off site for oil separation and distillation process in the refrigerant is sold back to the industry as a new refrigerant

  • 31

    Which method of charging should be used when working on air conditioning system utilizing a TX valve

    subcooling method

  • 32

    Which method of charging should be used when working on an air conditioning system utilizing a fixed orifice

    superheat method

  • 33

    Which of the following terms best to scratch reuse

    take refrigerant out of the air conditioning unit and place it in an approved container and return the refrigerant to the system once repaired

  • 34

    Heating and cooling thermostats react to

    sensible heat only

  • 35

    The closing force of the TX valve is provided by

    evaporator pressure

  • 36

    The opening force of a TX valve is provided by

    the sensing ball pressure

  • 37

    What condition could cause liquid refrigerant to load backup to the condenser

    metering device offices to restrictive

  • 38

    If an a evaporator coil is found with one half frosting and the other half condensating what is the problem

    one of the capillary tubes is plugged

  • 39

    If the water regulating valve on a water cool condensers restricted the head pressure will

    increase

  • 40

    If a 5uf capacitor and 15uf capacitors are placed in series with each other the resulting capacitance will be

    3.75uf

  • 41

    If a 5uf capacitor in a 15uf good pastor our place in parallel with each other the resulting capacitor will be

    20uf

  • 42

    Condensing refrigerant

    change of States not temperature

  • 43

    The amount of latent heat required to change 1 lb of water to 1 lb of steam is

    970 BTU

  • 44

    The amount of latent heat required to change 1 lb of water to 1 lb of ice is

    144 BTU

  • 45

    Sensible heat is defined as

    a change of temperature of a substance without change of state

  • 46

    Latent heat is defined as

    a change of state of a substance without a change of temperature

  • 47

    Enthalpy is defined as

    the total amount of heat removed to change the substance

  • 48

    A 35uf, 440v capacitor is faulty in a residential air conditioning unit the technician could replace a capacitor with which of the following choices placed in parallel with each other

    20uf, 440v capacitor, 12.5uf 570v capacitor

  • 49

    The technician must replace a 40uf, 440v capacitor,

    38uf, 440v capacitor

  • 50

    Heat anticipators are

    installed in series with the gas valve

  • 51

    No suction pressure in the air conditioning system could be caused by

    all the above

  • 52

    Evaporating substance

    will absorb heat

  • 53

    Superheat is found

    in the suction line

  • 54

    Proper amount of subcooling indicates

    proper refrigerant charge, condenser functioning properly

  • 55

    Proper amount of superheat indicates

    proper refrigerant charge, evaporator functioning properly

  • 56

    Which of the following refrigerants is a blend of different refrigerants

    R 410A

  • 57

    Crankcase heater is used for

    prevents liquid from migrating in the compressor

  • 58

    Electricity is the flow of

    Valencia electrons

  • 59

    The motor and compressor loads require which types of fuses

    Type D fuse

  • 60

    Fuse are connected

    in series with the load being protected

  • 61

    A reading of 0 volts is obtained across an energized fuse which means

    fuse is good

  • 62

    Fuse will blow if excessive................. is present?

    amperage

  • 63

    Electromotive force is measured using

    voltmeter

  • 64

    The wiring found in a residential breaker panel is

    240/120 volt, 1 phase, 60 Hz

  • 65

    As a humidity and a condition space rises, the temperature difference across evaporator will?

    decrease

  • 66

    When fresh air is introduced to a home for ventilation purposes

    all of the above

  • 67

    Which of the following gases is the most dangerous to pressure test and air conditioning system wet

    oxygen

  • 68

    fractionation is a concern when using?

    R410A

  • 69

    Which of the following instruments is used to measure inches of water column?

    manometer

  • 70

    Which of the following instrument utilizes a hot wire?

    Anemomter

  • 71

    Which of the following instruments is used to measure wet bulb temperature?

    psychrometer

  • 72

    On the diagram on the previous page the refrigerant should be in what state at point a

    low pressure, medium temperature, vapor

  • 73

    On the diagram on the previous page the refrigerant should be in what state at point b

    high pressure, high temperature, vapor

  • 74

    On the diagram on the previous page the refrigerant should be in what state at point C

    high pressure, medium temperature, liquid

  • 75

    In the diagram the refrigerant should be at what state at point D

    low pressure, low temperature, liquid

  • 76

    Which of the following devices would help solve low suction pressure conditions

    low ambient control

  • 77

    A magnahelic gauge can be used to determine

    duck static pressure CFM

  • 78

    If an air conditioning system has a non-bleed t type TXV valve installed, what component should also be installed on the compressor

    hard start kit

  • 79

    Which of the following conditions will cause the head pressure to rise

    low condenser air flow

  • 80

    Which of the following conditions can cause evaporator to freeze up

    Open bypass humidifier damper

  • 81

    If a technician finds a zone damper motor that is seized what should be done?

    replace the damper motor, reactivate, and test the damper motor

  • 82

    A zone damper that fails to open could cause

    can cause low suction pressure for a heat pump in cooling mode

  • 83

    A reversing valve on a heat pump has

    2 inlets and 2 outlets

  • 84

    The main reason for nitrogen spewing during grazing is

    to remove oxygen from inside at the tubing

  • 85

    A reversing valve that has an internal leak will cause

    decrease in the liquid temperature in the condenser

  • 86

    The first law of thermodynamics states

    heat cannot be created or destroyed

  • 87

    Which of the following is a concern with r410a

    operating pressures are much higher than r22

  • 88

    How much refrigerant pressure is required to change the position of the reversing valve on a heat pump

    75 PSI

  • 89

    The definition of BTU is?

    the amount of heat required to raise 1 lb of water 1° f

  • 90

    If the suction pressure is 72 PSIG in the suction temperature line is 42° f in a r22 system the compressor is safe?

    no, because liquid vision could enter the compressor

  • 91

    An equalizing line on an external equalizing TX valve will connect the valve body to

    evaporate outlet downstream of the sensing bulb

  • 92

    The reversing valve is found?

    on a heat pump system

  • 93

    He probably operating reversing valve well

    only change positions on a call for a cooling

  • 94

    Charging system with r410a

    both A and C

  • 95

    Is it ever acceptable to install an evaporator in the return air duct of a furnace

    yes

  • 96

    When implying heat to a joint being a braised what vision will indicate that joint is hot enough to add filler alloy

    the flux will turn to a clear liquid

  • 97

    Copper tubing glows red in color at what temperature

    1800 degrees Fahrenheit

  • 98

    When checking for continuity the meter use would be

    ohmmeter

  • 99

    When checking for current the meter use would be

    ammeter

  • 100

    When checking for resistance the meter use would be

    ohm meter

    • 313 4th attempt

    313 4th attempt

    Modder One · 124問 · 1年前

    313 4th attempt

    313 4th attempt

    124問 • 1年前
    Modder One

    問題一覧

  • 1

    The amount of latent heat required to change 1 lb of water to 1 lb of steam

    970 btu

  • 2

    The amount of latent heat required to change one pound of water to 1 lb of ice

    144 btu

  • 3

    Which method of charging should be used when working on an air conditioning system utilizing a TX valve

    Sub cooling method

  • 4

    Which method of charging should be used when working on an air conditioning system utilizing a fixed orifice

    super heat method

  • 5

    A heat pump with a reversing valve that is leaking internally will cause

    high suction pressure and low discharge pressure

  • 6

    If a new air conditioning system is installed with a 45-ft line set and the unit is pre-charged with a refrigerant for a 15-ft line set in the insulation instructions indicate to add 6 oz for each additional foot of line set to correctly charge the equipment the technician would

    at 18 Oz (1 lb 2 oz) of refrigerant

  • 7

    The most common type of compressor found in a residential air conditioning is

    permanent split capacitor

  • 8

    The type of soft copper used in residential air conditioning system is

    type L

  • 9

    The capacitor on a capacitor start induction run compressor is

    in series with the start winding

  • 10

    The vacuum pump is used too

    remove oxygen and moisture from the air conditioning system

  • 11

    A clogged furnace air filter will cause

    low suction line pressure

  • 12

    Which revision listed below will not deplete the ozone layer

    R410A

  • 13

    HFC refrigerant do not contain

    Chlorine

  • 14

    When the line set on an installed air conditioning system is longer than 50 ft and length the technician should

    refer to the insulation instructions

  • 15

    The term LRA stands for

    locked rotor amperage

  • 16

    The electrical supply to residential gas furnace is

    120v, 1 phase, 60 Hz

  • 17

    The contacts on a potential relay are?

    normally closed

  • 18

    Cooling anticipators are resistors in the thermostat that

    provide a false heat load in the off-cycle of the air conditioning system

  • 19

    The minimum CFM required across an evaporator in an air conditioning system

    350 CFM

  • 20

    If an air conditioning system is not functioning in your call to a service equipment the following parameters are found 1. Compressor not operating 2. condenser fan not operating 3. 24 volts found across the contactor coil 4. 240 volts found on the line side of the contactor 5. 120 volts found across contacts 6. 1.2ohms reading across condenser fan motor windings 7. 1.5ohms reading across compressor R & C windings, 3ohms S and R compressor S and C windings and 4.5ohms across S and R windings 8. Compressor capacitor reads 33uf (35 is normal) 9. Condenser fan capacitor reads 4.8uf (5 is normal) What is the problem?

    the contactor is defective

  • 21

    If an air conditioning system is not functioning in your call to the service the equipment the following parameters are found X. Compressor not operating XI. Condenser fan operating XII. 24 volts found across contactor coil XIII. 240 volts found on the line side of the contactor XIV. 0 volts found across contactors contacts XV. 1.2ohms reading across condenser fan motor windings XVI. Infinity ohms reading a cross compressor RNC windings, Infinity readig across S & C windings, 4.5ohms reading across S&R compressor windings XVII. Compressor capacitor reads 33ohms (35 is normal) XVIII. Condenser fan capacitor reads 4.8 ohms (5 is normal)

    the compressor has thermal overload

  • 22

    If an air conditioning system is not functioning in your your call to a service equipment the following parameters are found 1. Compressor not operating 2. Condenser fan operating 3. 24 volts found across contact coil 4. 240 volts found on the line side of the contactor 5. 0 volts found a cross contactor contacts 6. 1.2ohms reading across condenser fan motor windings 7. 1.5ohms reading across compressor R & C windings, 3.0ohms reading across compressor S & C windings, 4.5ohms reading across S & R windings 8. Compressor capacitor reads OL (35uF is normal) 9. Condenser fan capacitor reading 4.8uF (5uF is normal)

    the compressor capacitor is defective

  • 23

    Relays are not available in what?

    triple throw models

  • 24

    On a combination fan and limit control the three tabs represent looking from left to right on the control

    fan off, fan on, high limit

  • 25

    The w terminal on the board of a furnace is used to

    enable the gas valve

  • 26

    Which of the following terms best describes recovery

    take refrigerant out of the air conditioning unit and place it in an approved container

  • 27

    Which of the following terms best describes recycle

    take refrigerant out of the air conditioning unit and place it and approved container put the refrigerant through an on-site oil separation distillation process and return the refrigerant to the system once prepared

  • 28

    Hcfc refrigerants will not be available after

    in January 1st 2030

  • 29

    CFC refrigerants will not be available after

    CFC refrigerants are already banned

  • 30

    Which of the following terms best describe reclaim

    take refrigerant out of the air conditioning unit and place it in approved container send refrigerant off site for oil separation and distillation process in the refrigerant is sold back to the industry as a new refrigerant

  • 31

    Which method of charging should be used when working on air conditioning system utilizing a TX valve

    subcooling method

  • 32

    Which method of charging should be used when working on an air conditioning system utilizing a fixed orifice

    superheat method

  • 33

    Which of the following terms best to scratch reuse

    take refrigerant out of the air conditioning unit and place it in an approved container and return the refrigerant to the system once repaired

  • 34

    Heating and cooling thermostats react to

    sensible heat only

  • 35

    The closing force of the TX valve is provided by

    evaporator pressure

  • 36

    The opening force of a TX valve is provided by

    the sensing ball pressure

  • 37

    What condition could cause liquid refrigerant to load backup to the condenser

    metering device offices to restrictive

  • 38

    If an a evaporator coil is found with one half frosting and the other half condensating what is the problem

    one of the capillary tubes is plugged

  • 39

    If the water regulating valve on a water cool condensers restricted the head pressure will

    increase

  • 40

    If a 5uf capacitor and 15uf capacitors are placed in series with each other the resulting capacitance will be

    3.75uf

  • 41

    If a 5uf capacitor in a 15uf good pastor our place in parallel with each other the resulting capacitor will be

    20uf

  • 42

    Condensing refrigerant

    change of States not temperature

  • 43

    The amount of latent heat required to change 1 lb of water to 1 lb of steam is

    970 BTU

  • 44

    The amount of latent heat required to change 1 lb of water to 1 lb of ice is

    144 BTU

  • 45

    Sensible heat is defined as

    a change of temperature of a substance without change of state

  • 46

    Latent heat is defined as

    a change of state of a substance without a change of temperature

  • 47

    Enthalpy is defined as

    the total amount of heat removed to change the substance

  • 48

    A 35uf, 440v capacitor is faulty in a residential air conditioning unit the technician could replace a capacitor with which of the following choices placed in parallel with each other

    20uf, 440v capacitor, 12.5uf 570v capacitor

  • 49

    The technician must replace a 40uf, 440v capacitor,

    38uf, 440v capacitor

  • 50

    Heat anticipators are

    installed in series with the gas valve

  • 51

    No suction pressure in the air conditioning system could be caused by

    all the above

  • 52

    Evaporating substance

    will absorb heat

  • 53

    Superheat is found

    in the suction line

  • 54

    Proper amount of subcooling indicates

    proper refrigerant charge, condenser functioning properly

  • 55

    Proper amount of superheat indicates

    proper refrigerant charge, evaporator functioning properly

  • 56

    Which of the following refrigerants is a blend of different refrigerants

    R 410A

  • 57

    Crankcase heater is used for

    prevents liquid from migrating in the compressor

  • 58

    Electricity is the flow of

    Valencia electrons

  • 59

    The motor and compressor loads require which types of fuses

    Type D fuse

  • 60

    Fuse are connected

    in series with the load being protected

  • 61

    A reading of 0 volts is obtained across an energized fuse which means

    fuse is good

  • 62

    Fuse will blow if excessive................. is present?

    amperage

  • 63

    Electromotive force is measured using

    voltmeter

  • 64

    The wiring found in a residential breaker panel is

    240/120 volt, 1 phase, 60 Hz

  • 65

    As a humidity and a condition space rises, the temperature difference across evaporator will?

    decrease

  • 66

    When fresh air is introduced to a home for ventilation purposes

    all of the above

  • 67

    Which of the following gases is the most dangerous to pressure test and air conditioning system wet

    oxygen

  • 68

    fractionation is a concern when using?

    R410A

  • 69

    Which of the following instruments is used to measure inches of water column?

    manometer

  • 70

    Which of the following instrument utilizes a hot wire?

    Anemomter

  • 71

    Which of the following instruments is used to measure wet bulb temperature?

    psychrometer

  • 72

    On the diagram on the previous page the refrigerant should be in what state at point a

    low pressure, medium temperature, vapor

  • 73

    On the diagram on the previous page the refrigerant should be in what state at point b

    high pressure, high temperature, vapor

  • 74

    On the diagram on the previous page the refrigerant should be in what state at point C

    high pressure, medium temperature, liquid

  • 75

    In the diagram the refrigerant should be at what state at point D

    low pressure, low temperature, liquid

  • 76

    Which of the following devices would help solve low suction pressure conditions

    low ambient control

  • 77

    A magnahelic gauge can be used to determine

    duck static pressure CFM

  • 78

    If an air conditioning system has a non-bleed t type TXV valve installed, what component should also be installed on the compressor

    hard start kit

  • 79

    Which of the following conditions will cause the head pressure to rise

    low condenser air flow

  • 80

    Which of the following conditions can cause evaporator to freeze up

    Open bypass humidifier damper

  • 81

    If a technician finds a zone damper motor that is seized what should be done?

    replace the damper motor, reactivate, and test the damper motor

  • 82

    A zone damper that fails to open could cause

    can cause low suction pressure for a heat pump in cooling mode

  • 83

    A reversing valve on a heat pump has

    2 inlets and 2 outlets

  • 84

    The main reason for nitrogen spewing during grazing is

    to remove oxygen from inside at the tubing

  • 85

    A reversing valve that has an internal leak will cause

    decrease in the liquid temperature in the condenser

  • 86

    The first law of thermodynamics states

    heat cannot be created or destroyed

  • 87

    Which of the following is a concern with r410a

    operating pressures are much higher than r22

  • 88

    How much refrigerant pressure is required to change the position of the reversing valve on a heat pump

    75 PSI

  • 89

    The definition of BTU is?

    the amount of heat required to raise 1 lb of water 1° f

  • 90

    If the suction pressure is 72 PSIG in the suction temperature line is 42° f in a r22 system the compressor is safe?

    no, because liquid vision could enter the compressor

  • 91

    An equalizing line on an external equalizing TX valve will connect the valve body to

    evaporate outlet downstream of the sensing bulb

  • 92

    The reversing valve is found?

    on a heat pump system

  • 93

    He probably operating reversing valve well

    only change positions on a call for a cooling

  • 94

    Charging system with r410a

    both A and C

  • 95

    Is it ever acceptable to install an evaporator in the return air duct of a furnace

    yes

  • 96

    When implying heat to a joint being a braised what vision will indicate that joint is hot enough to add filler alloy

    the flux will turn to a clear liquid

  • 97

    Copper tubing glows red in color at what temperature

    1800 degrees Fahrenheit

  • 98

    When checking for continuity the meter use would be

    ohmmeter

  • 99

    When checking for current the meter use would be

    ammeter

  • 100

    When checking for resistance the meter use would be

    ohm meter