Question 1

The TXV sensing bulb is mounted ____.

Accepted Answer

A)   on the liquid line between the condenser and the TXV
B)   at the inlet to the condenser
C)   on the suction line between the evaporator and the compressor
D)   on the compressor discharge lineE) B) and C)
F) A) and D)

Question 2

Explain the recommended method of charging a system with a capillary tube system.

Accepted Answer

Manufacturers do not recommend...

Question 3

When the evaporator pressure drops, the automatic expansion valve will open to allow more refrigerant to enter the evaporator .

Accepted Answer

A) True 
 B)False  True

Question 4

Why should the TXV be adjusted to maintain a low superheat ?

Accepted Answer

To ensure that the majority of...

Question 5

Balanced port TXVs are used to ____ ambient temperatures .

Accepted Answer

A)   feed refrigerant at a normal rate with low
B)   feed refrigerant at a normal rate with high
C)   stop refrigerant flow with high
D)   stop refrigerant flow with lowE) A) and D)
F) B) and C)

Question 6

A capillary tube metering device controls the refrigerant flow by pressure drop .

Accepted Answer

A) True 
 B)False

Question 7

The purpose of an external equalizer in a TXV is to ____.

Accepted Answer

A)   compensate for excessive evaporator pressure drop
B)   allow system to equalize faster
C)   prevent the expansion valve from frosting up
D)   allow refrigerant to expand in the compressorE) A) and B)
F) A) and C)

Question 8

Pressure entering the compressor that is too high will cause the density of suction gases entering the compressor to increase .

Accepted Answer

A) True 
 B)False

Question 9

When is an external equalizer-type TXV required?

Accepted Answer

This is required whe...

Question 10

The purpose of a capillary tube is to ____.

Accepted Answer

A)   regulate the refrigerant flow into the evaporator
B)   lower the pressure of the liquid refrigerant
C)   lower the boiling point of the refrigerant
D)   All of the above.E) A) and B)
F) B) and C)

Question 11

The step-motor valve uses a small motor to control the valve's port, which in turn controls evaporator superheat.

Accepted Answer

A) True 
 B)False

Question 12

The solid-state controlled step-motor valve has a temperature sensor, or thermistor, as one of its inputs .

Accepted Answer

A) True 
 B)False

Question 13

If a thermostatic expansion valve's thermal bulb came loose from the suction line at the outlet of the evaporator, which of the following could result?

Accepted Answer

A)   The bulb pressure would increase and the thermostatic expansion valve would open.
B)   The superheat in the evaporator would decrease.
C)   The evaporating pressure and the compressor's suction pressure would increase .
D)   All of the above are correct.E) B) and C)
F) All of the above

Question 14

What two pressures control the operation of an automatic expansion valve?

Accepted Answer

They are the spring pressure and evaporator pressure.

Question 15

As the evaporator load increases, an automatic expansion valve will ____________________ to maintain the suction pressure at the set point .

Accepted Answer

The answer of As the evaporator load increases, an automatic...

Question 16

The TXV maintains a constant ____________________ in the evaporator .

Accepted Answer

The answer of The TXV maintains a constant ____________________ in...

Question 17

When the load on the evaporator increases, the TXV ____.

Accepted Answer

A)   increases the flow of refrigerant
B)   decreases the flow of refrigerant
C)   maintains constant head pressure
D)   decreases the pressure drop across the evaporatorE) B) and C)
F) A) and B) A

Question 18

The two pressures that push to close a thermostatic expansion valve are the ____________________ pressure and the evaporator pressure.

Accepted Answer

The answer of The two pressures that push to close...

Question 19

The cross liquid charge bulb at the TXV contains fluid that ____.

Accepted Answer

A)   has similar characteristics to the system fluid to prevent liquid refrigerant from entering the suction line
B)   has different characteristics from the system fluid
C)   causes the valve to stay open during the off cycle
D)   follows the system's pressure-temperature relationshipE) All of the above
F) None of the above

Question 20

An automatic expansion valve uses a thermal bulb to help control the amount of refrigerant being fed into the evaporator.

Accepted Answer

A) True 
 B)False

Exam 24: Expansion Devices

The TXV sensing bulb is mounted ____.

Correct AnswerverifiedShow Answer

Explain the recommended method of charging a system with a capillary tube system.

Correct AnswerverifiedManufacturers do not recommend...View AnswerShow Answer

When the evaporator pressure drops, the automatic expansion valve will open to allow more refrigerant to enter the evaporator .

Correct AnswerverifiedTrue

Why should the TXV be adjusted to maintain a low superheat ?

Correct AnswerverifiedTo ensure that the majority of...View AnswerShow Answer

Balanced port TXVs are used to ____ ambient temperatures .

Correct AnswerverifiedShow Answer

A capillary tube metering device controls the refrigerant flow by pressure drop .

Correct AnswerverifiedShow Answer

The purpose of an external equalizer in a TXV is to ____.

Correct AnswerverifiedShow Answer

Pressure entering the compressor that is too high will cause the density of suction gases entering the compressor to increase .

Correct AnswerverifiedShow Answer

When is an external equalizer-type TXV required?

Correct AnswerverifiedThis is required whe...View AnswerShow Answer

The purpose of a capillary tube is to ____.

Correct AnswerverifiedShow Answer

The step-motor valve uses a small motor to control the valve's port, which in turn controls evaporator superheat.

Correct AnswerverifiedShow Answer

The solid-state controlled step-motor valve has a temperature sensor, or thermistor, as one of its inputs .

Correct AnswerverifiedShow Answer

If a thermostatic expansion valve's thermal bulb came loose from the suction line at the outlet of the evaporator, which of the following could result?

Correct AnswerverifiedShow Answer

What two pressures control the operation of an automatic expansion valve?

Correct AnswerverifiedThey are the spring pressure and evaporator pressure.

As the evaporator load increases, an automatic expansion valve will ____________________ to maintain the suction pressure at the set point .

Correct AnswerverifiedShow Answer

The TXV maintains a constant ____________________ in the evaporator .

Correct AnswerverifiedShow Answer

When the load on the evaporator increases, the TXV ____.

Correct AnswerverifiedA

The two pressures that push to close a thermostatic expansion valve are the ____________________ pressure and the evaporator pressure.

Correct AnswerverifiedShow Answer

The cross liquid charge bulb at the TXV contains fluid that ____.

Correct AnswerverifiedShow Answer

An automatic expansion valve uses a thermal bulb to help control the amount of refrigerant being fed into the evaporator.

Correct AnswerverifiedShow Answer

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Manufacturers do not recommend...
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True

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To ensure that the majority of...
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This is required whe...
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They are the spring pressure and evaporator pressure.

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A

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