Question 1

Manifold gauge should be calibrated for accuracy on a regular basis. A good quality gauge will be accurate to within ______ over the range of its scale when properly calibrated.&#10;A) 1%&#10;B) 2%&#10;C) 3%&#10;D) 4%

Accepted Answer

A good quality gauge will be accurate to within 2% over the range of its scale when properly calibrated. Therefore, option B is the best choice. The other options are either too low or too high, which does not reflect the accuracy of a well-calibrated manifold gauge.

Question 2

Of the following refrigerant leak detection methods which one would be the most sensitive?&#10;A) Flame type leak detector&#10;B) Electronic leak detector&#10;C) Ultraviolet leak detector&#10;D) Soapsud solution

Accepted Answer

Electronic leak detectors are known to be the most sensitive of the options listed, able to detect minute leaks of refrigerant. Flame type leak detectors rely on a flame reacting to the presence of refrigerant, which may not be as reliable or sensitive. Ultraviolet leak detectors require the use of a special dye added to the refrigerant, and may not be as effective at detecting small leaks. Soapsud solution is a low-tech method that involves applying soapy water to potential leak areas and looking for bubbles, but this is also not as reliable or sensitive as an electronic leak detector.

Question 3

When a technician uses a manifold gauge set to evacuate an air conditioning system what position should the technician position the hand valves in order to evacuate both sides of the system?&#10;A) High pressure hand valve open and low press hand valve closed&#10;B) High pressure hand valve closed and low pressure hand valve open&#10;C) High pressure hand valve open and low pressure hand valve open&#10;D) High pressure hand valve closed and low pressure hand valve closed

Accepted Answer

To evacuate both sides of an air conditioning system effectively, a technician should open both the high pressure and low pressure hand valves on the manifold gauge set. This allows the vacuum pump to remove air and moisture from both the high and low sides of the system.

Question 4

Which of the following statements regarding changing vacuum pump oil change interval is NOT correct?&#10;A) Vacuum pump oil should be changed whenever a system is evacuated on a system known to have high moisture content.&#10;B) Vacuum pump oil should be changed whenever a system is known to have been contaminated is evacuated.&#10;C) Vacuum pump oil should be changed after each use.&#10;D) Vacuum pump oil should be changed whenever the pump will not pull to the desired level of vacuum.

Accepted Answer

Vacuum pump oil does not need to be changed after each use. The interval for oil changes depends on the individual system and the type of oil being used. It is important to regularly monitor the oil's condition and change it as necessary based on the manufacturer's recommendations.

Question 5

What would the recommended vacuum pump size be for a typical truck air conditioning system?&#10;A) 1 to 2 cubic feet per minute&#10;B) 2 to 3 cubic feet per minute&#10;C) 3 to 4 cubic feet per minute&#10;D) 4 to 6 cubic feet per minute

Accepted Answer

A vacuum pump between 4 and 6 cubic feet per minute is the recommended size for a typical truck air conditioning system. This is because the larger size will be able to quickly pull a deep vacuum and remove any moisture or air from the system, leading to better performance and longevity of the AC system.

Question 6

Of the following refrigerant leak detection methods which one would work best for detecting hot or cold leaks?&#10;A) Flame type leak detector&#10;B) Electronic leak detector&#10;C) Ultraviolet leak detector&#10;D) Soapsud solution

Accepted Answer

Ultraviolet leak detectors work by using a UV dye that is added to the refrigerant. When the dye leaks out with the refrigerant, it can be detected under UV light. This method is best for detecting both hot and cold leaks as the dye remains visible even at very low temperatures.

Question 7

A compressor can be removed from an air conditioning system without removing all the refrigerant from the system if ________ are used.&#10;A) Schrader valves&#10;B) R-134a style refrigerant valves&#10;C) Stem type service valves&#10;D) Manifold service valves

Accepted Answer

Stem type service valves can be closed to isolate the section of the system that contains the compressor, allowing it to be removed without losing refrigerant from the entire system. Schrader valves and R-134a style refrigerant valves are used for accessing the refrigerant system for pressure readings and adding or removing refrigerant, but they do not allow for isolation of specific parts of the system. Manifold service valves are used for connecting gauges and other tools for testing and servicing the system, but they also do not allow for isolation of specific parts of the system.

Question 8

Which of the following is NOT true when evacuating an air conditioning system?&#10;A) Air is removed&#10;B) Moisture is removed&#10;C) Contaminates are removed&#10;D) Refrigerant is removed

Accepted Answer

Evacuating an air conditioning system involves removing air, moisture, and contaminants from the system. However, refrigerant is not supposed to be removed during the evacuation process.

Question 9

Identify the INCORRECT procedure when charging and air conditioning system with a manifold gauge set and an accurate weigh scale.&#10;A) Purge the yellow service hose from the refrigerant cylinder to the manifold.&#10;B) Charge using liquid refrigerant through the red high pressure hose.&#10;C) Finish charging with vaporous refrigerant through the blue low pressure hose with the vehicles compressor running until the correct charge by weight is installed.&#10;D) Finish charging with liquid refrigerant through the blue low pressure hose with the vehicles compressor running until the correct charge by weight is installed.

Accepted Answer

Finishing the charging process with liquid refrigerant through the blue low pressure hose is incorrect because it can cause liquid slugging in the compressor. The correct procedure is to finish charging with vaporous refrigerant through the blue low pressure hose with the vehicle's compressor running until the correct charge by weight is installed.

Question 10

If charging a vehicle using a refrigerant charging cylinder you may not need to operate the vehicles compressor if the cylinder is equipped with a ____________?&#10;A) Pump&#10;B) Heater&#10;C) Pressurization cylinder&#10;D) Compressed air fitting

Accepted Answer

A heater in the refrigerant charging cylinder can increase the pressure of the refrigerant, allowing it to flow into the vehicle's air conditioning system without the need for the vehicle's compressor to operate. This is because heating the refrigerant increases its pressure, pushing it into the system.

Question 11

A standard manifold gauge set has three color coded hoses attached to the manifold. Of the following, identify the INCORRECT statement.&#10;A) The red line will cause the high pressure gauge to read pressure when attached to a source.&#10;B) The blue line will cause the compound gauge to read low pressure or vacuum when attached to a source.&#10;C) The yellow line is the service line and is used for evacuation or to add or remove refrigerant.&#10;D) The green line attaches to the port of the accumulator and will read the systems high pressure.

Accepted Answer

The answer of A standard manifold gauge set has three...

Question 12

Refrigerant identifies are used to test the purity of refrigerant in an air conditioning system. What would be the minimum acceptable level of purity?&#10;A) 100%&#10;B) 99%&#10;C) 98%&#10;D) 97%

Accepted Answer

The answer of Refrigerant identifies are used to test the...

Question 13

What tool would be the best choice to ensure that there are no leaks in an air conditioning system?&#10;A) A vacuum pump&#10;B) A refrigerant identifier&#10;C) The compound gauge on the manifold&#10;D) A thermistor vacuum gauge

Accepted Answer

The answer of What tool would be the best choice...

Question 14

Of the following refrigerant leak detection methods which one would be the simplest?&#10;A) Flame type leak detector&#10;B) Electronic leak detector&#10;C) Ultraviolet leak detector&#10;D) Soapsud solution

Accepted Answer

The answer of Of the following refrigerant leak detection methods...

Question 15

When installing a gauge hose on a R-134a system the gauge will only read system pressure once:&#10;A) The spring loaded collar has been pulled back&#10;B) The coupler has been installed and the hand valve has been back seated&#10;C) The coupler has been installed and hand valve had been front seated&#10;D) The protective valve cap has been removed

Accepted Answer

The answer of When installing a gauge hose on a...

Deck 7: Service Procedures