Free Practice Quiz Question List

3 Evacuating Low-Pressure Systems Online Quiz Questions

Use this free practice quiz with 20 questions to review 3 Evacuating Low-Pressure Systems, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

A conventional compound gauge can reliably measure the deep vacuum needed for chiller dehydration.

A
True
B
False

Choose one

1 point

During refrigerant removal from a low-pressure chiller, how should a technician protect the heat-exchanger water circuits?

A
Always drain every water circuit before refrigerant removal, regardless of the manufacturer’s procedure.
B
Maintain or remove water as the manufacturer specifies to prevent freezing in heat-exchanger tubes.
C
Leave water in the circuits and use compressed air to protect the tubes.

Choose all

1 point

Which choices are appropriate parts of a dehydration-evacuation setup? Select all that apply.

A
Use clean pump oil.
B
Use a conventional compound gauge as the instrument for measuring deep vacuum.
C
Use vacuum-rated, large-diameter hoses.
D
Use suitable isolation valves or a vacuum manifold.

Choose all

1 point

Why is it important to remove moisture from a low-pressure chiller? Select all supported effects.

A
It can freeze.
B
It can corrode components.
C
It guarantees that leaks will draw refrigerant out of a low-pressure system.
D
It can contribute to acid and sludge formation.

Choose one

1 point

Where should the micron gauge be placed during dehydration evacuation, and why?

A
At the vacuum pump, because the pump-side reading represents the chiller’s actual vacuum.
B
At the chiller, or as close to it as practical, because hose pressure drop can make the pump-side reading appear better than the system’s actual vacuum.
C
At the far end of the longest hose, because maximizing pressure drop improves measurement accuracy.
D
On a conventional compound gauge, because it reliably measures deep vacuum.

Written response

1 point

The listed EPA recovery evacuation level for low-pressure appliances is 25 mm Hg absolute. Express this level in microns.

Fill in the blank

1 point

Removing air and moisture after a system is sealed and leak-tested is ; removing refrigerant before the system is opened is .

Choose one

1 point

A valve is left closed between the pump and one section that requires evacuation. What is the likely consequence?

A
The vacuum pump will automatically evacuate the isolated section through the closed valve.
B
The isolated section will dry faster because it is protected from the pump.
C
The isolated section may remain undried because it is not connected to the pump.
D
The micron gauge will measure the isolated section’s pressure regardless of its location.

True or false

1 point

A standing vacuum test can help assess system tightness and dryness behavior, but it cannot by itself identify the location of a leak.

A
True
B
False

Written response

1 point

What instrument is used to measure absolute pressure during deep-vacuum evacuation?

Fill in the blank

1 point

In triple evacuation, the vacuum is broken with , and the process is repeated at .

Open ended

1 point

Describe how to perform and evaluate a standing-vacuum check after evacuating a chiller. Include the pump and gauge positions, what to observe, and what to do if the check fails.

True or false

1 point

When breaking a vacuum, dry nitrogen may be used as directed, but oxygen and compressed air must not be used.

A
True
B
False

Choose one

1 point

During dehydration, a pump-side reading suggests a deeper vacuum than expected at the chiller. Where should the micron gauge be placed to monitor the system’s actual vacuum most reliably?

A
Place the micron gauge beside the vacuum pump.
B
Place the micron gauge at the chiller, or as close to it as practical.
C
Use a compound gauge at the pump instead of a micron gauge.
D
Disconnect the gauge once the pump reaches its target.

Written response

1 point

For an EPA Section 608 refrigerant-recovery requirement, what absolute pressure, expressed in microns, is the listed evacuation level for a low-pressure appliance? Enter the numeric value in microns.

Choose one

1 point

A low-pressure system has been exposed to moisture during substantial repair, and the applicable procedure calls for the example triple-evacuation sequence described in the material. Which sequence matches that example?

A
Reach 500 microns, break the vacuum with oxygen, then stop without checking the system.
B
Pressurize with compressed air, evacuate once to 1,500 microns, and leave the pump connected.
C
Evacuate to 1,500 microns, isolate the pump and break the vacuum with dry nitrogen; repeat at 1,000 microns and then 500 microns, followed by a standing-vacuum check.
D
Evacuate to 1,000 microns, open the system to atmosphere, and finish at 1,500 microns.

Written response

1 point

What type of pressure does a micron gauge measure?

Choose one

1 point

During a standing-vacuum check, pressure rises slowly and continues to rise. Which set of causes is consistent with this behavior?

A
Moisture outgassing, refrigerant remaining in oil, or a leak.
B
A confirmed leak at the exact location of the gauge.
C
A normal result that proves the system is dry and leak-free.
D
A compound gauge converting the reading from absolute pressure.

Choose one

1 point

A technician must break a vacuum during a staged dehydration procedure. Which action is consistent with the material’s safety guidance?

A
Use oxygen because it contains no moisture, and pressurize until the system reaches atmospheric pressure.
B
Use compressed air at a pressure above the system’s allowable limit to speed the process.
C
Use any available gas if the pump is isolated first.
D
Use dry nitrogen safely according to equipment instructions, without exceeding the system’s allowable pressure.

Choose one

1 point

After leak testing, a technician discovers that a closed valve has isolated one section that must be dehydrated. What should be done before evacuation proceeds?

A
Leave the valve closed because the vacuum pump will evacuate the isolated section through the chiller walls.
B
Open or isolate valves as directed by the manufacturer so every section requiring evacuation is connected to the pump.
C
Close every valve and evacuate only the section nearest the pump.
D
Remove the micron gauge so the isolated section can equalize.

3 Evacuating Low-Pressure Systems Online Quiz Questions

Related study packs and tools