Free Practice Quiz Question List

2 Refrigerant Pressures and Pressure-Temperature Charts Online Quiz Questions

Use this free practice quiz with 20 questions to review 2 Refrigerant Pressures and Pressure-Temperature Charts, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

For the same refrigerant, increasing pressure raises its saturation temperature.

A
True
B
False

Choose one

1 point

At 70°F saturation, about what pressure does the cited Sporlan chart list for R-134a?

A
About 121.4 psig
B
About 71.1 psig
C
About 201.8 psig
D
About 14.7 psig

Written response

1 point

At saturation, which two phases of a refrigerant can coexist?

Fill in the blank

1 point

For some refrigerant blends, the temperature difference during evaporation or condensation at nearly constant pressure is called .

Choose one

1 point

A technician needs to compare a pressure reading in psia with a value from the cited Sporlan chart, which reports psig at sea level. What should the technician do first?

A
Compare the numbers directly because psig and psia are interchangeable near sea level.
B
Convert the readings to the same pressure reference before comparing them.
C
Add the refrigerant’s saturation temperature to the psia reading.
D
Use a different refrigerant’s chart column to compensate for the unit difference.

Written response

1 point

Near sea level, use $P_{\text{psia}} \approx P_{\text{psig}} + 14.7\ \text{psi}$ . A gauge reads 38 psig. What is the approximate absolute pressure?

Choose all

1 point

Select all correct statements about dew point and bubble point for refrigerant blends.

A
Dew point is the saturated-vapor boundary used when calculating superheat.
B
Dew point is the saturated-liquid boundary used when calculating subcooling.
C
Bubble point is the saturated-liquid boundary used when calculating subcooling.
D
Bubble point is the saturated-vapor boundary used when calculating superheat.

Fill in the blank

1 point

In a typical vapor-compression system, the evaporator refrigerant must be cool enough to , while the condenser refrigerant must be warm enough to .

True or false

1 point

True or false: If a P–T chart gives a saturation temperature for a measured pressure, that result alone confirms that the system is correctly charged.

A
True
B
False

Choose one

1 point

A technician measures different pressures at a compressor and an evaporator coil. Which explanation is consistent with the material?

A
Pressure is always identical throughout a system when the refrigerant is saturated.
B
Compressor pressure must match the coil pressure if both readings use psig.
C
Pressure at the compressor may differ from pressure at a coil because of pressure drop in the lines.
D
The difference means the P–T chart must be for the wrong refrigerant.

Choose all

1 point

Select all factors listed in the material that can shift a system’s operating pressures.

A
Indoor and outdoor temperatures
B
Heating or cooling load
C
Airflow and coil cleanliness
D
The color of the equipment cabinet
E
Compressor operation, metering-device control, refrigerant charge, or pressure drop

Open ended

1 point

A technician sees a suction-pressure reading that differs from a value they expected and concludes that the system must be incorrectly charged. Explain why that conclusion is not justified by pressure alone, and describe what information or measurements should be considered instead.

Choose one

1 point

In a typical vapor-compression system, which statement best describes what suction and discharge pressures reflect?

A
Suction pressure reflects evaporator conditions, while discharge or condensing pressure reflects condenser conditions.
B
Suction pressure reflects condenser conditions, while discharge pressure reflects evaporator conditions.
C
Both pressures are determined only by the refrigerant name, not system conditions.
D
Discharge pressure is always a fixed value for a given system.

True or false

1 point

Near sea level, a pressure in psia is approximately the corresponding pressure in psig plus 14.7 psi.

A
True
B
False

Written response

1 point

The cited Sporlan chart lists about what saturation pressure for R-134a at 70°F? Enter the numeric value in psig; no conversion is needed.

Choose one

1 point

A technician finds a measured pressure on the correct refrigerant’s P–T chart. What temperature does the chart provide?

A
The refrigerant’s actual temperature at every point in the system.
B
The temperature of the compressor discharge line.
C
The refrigerant’s saturation temperature at that pressure.
D
The outdoor air temperature at the condenser.

Written response

1 point

For a refrigerant blend with temperature glide, which saturation boundary should be used when calculating superheat?

Choose one

1 point

A pressure measured at the compressor differs from a pressure measured at the evaporator coil. Which explanation is supported by the material?

A
Pressure drop through refrigerant lines may cause pressure at the compressor to differ from pressure at the coil.
B
Pressure at the compressor must always equal pressure at the coil.
C
A difference between the readings proves that the pressure gauge is faulty.
D
The coil pressure can be inferred exactly without considering line conditions.

Choose one

1 point

A system’s pressure readings change after its operating conditions change. Which conclusion is justified?

A
A system’s operating pressure is fixed once its refrigerant is selected.
B
Changes in operating conditions can shift the system’s operating pressures.
C
Only refrigerant charge can change operating pressure.
D
Outdoor conditions affect discharge pressure but cannot affect suction pressure.

Choose one

1 point

Which condition must the refrigerant’s saturation temperatures support for a typical vapor-compression system to transfer heat as intended?

A
The evaporator must be warmer than the space, and the condenser cooler than outdoor air.
B
Both the evaporator and condenser refrigerant must be at the same temperature as their surroundings.
C
The evaporator refrigerant must be cool enough to absorb heat, and the condenser refrigerant warm enough to reject it.
D
The condenser refrigerant must absorb heat, while the evaporator refrigerant rejects it.

2 Refrigerant Pressures and Pressure-Temperature Charts Online Quiz Questions

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