Refrigerant Machine Operator License Exam Prep Test

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  • 1/121 Questions

    OF THE FOLLOWING THE MOST CORRECT WAY TO DESCRIBE A BRAZED JOINT IS

    • PRESSURE FITTING
    • GAS TIGHT FITTING
    • START TO MELT AT 400°F
    • START TO MELT AT 500°F
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Refrigerant Machine Operator License Exam Prep Test - Quiz
About This Quiz

Below is a quiz on the refrigerant machine operator! It is designed to help an operator review all that they know about fridges and how to correct any defaults they may be experiencing. How about you give it a shot and get to see if all you know is enough to provide you with the certification. All the best of luck!

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  • 2. 

    R-22 IS:

    • ODORLESS

    • ETHER LIKE ODER WHEN MIXED WITH AIR

    • EXPLOSIVE

    • BOILS AT A HIGHER TEMPERATURE THAN R-12

    Correct Answer
    A. ODORLESS
    Explanation
    The given correct answer is "ODORLESS". This means that R-22 does not have a distinct smell.

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  • 3. 

    IN A COMPRESSOR'S ELECTRICAL BOX ONE OF THE HOT WIRES IS TOUCHING THE METAL BOX, WHAT WOULD MOST LIKELY HAPPEN?

    • COMPRESSOR WOULD OVERHEAT

    • COMPRESSOR WOULD OVERLOAD AND SHUT OFF

    • RMO WORKERS CAN RECEIVE ELECTRIC SHOCK IF THEY TOUCH IT

    • NOTHING

    Correct Answer
    A. RMO WORKERS CAN RECEIVE ELECTRIC SHOCK IF THEY TOUCH IT
    Explanation
    If one of the hot wires in a compressor's electrical box is touching the metal box, it can create an electrical fault. This can cause the metal box to become electrified, posing a risk of electric shock to anyone who touches it, including RMO workers. Therefore, the correct answer is that RMO workers can receive an electric shock if they touch it.

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  • 4. 

    COPPER USED IN REFRIGERATION SYSTEMS, LIKE IN HEAT EXCHANGERS, BECAUSE?

    • EASY FABRICATION

    • EASY DURABILITY

    • HIGH THERMAL CONDUCTIVITY

    • FLEXIBILITY

    Correct Answer
    A. HIGH THERMAL CONDUCTIVITY
    Explanation
    Copper is used in refrigeration systems, like in heat exchangers, because of its high thermal conductivity. Thermal conductivity refers to the ability of a material to conduct heat. Copper has one of the highest thermal conductivities among metals, allowing it to efficiently transfer heat. This is important in refrigeration systems as it helps in the rapid cooling and heat exchange process, ensuring efficient functioning of the system. Additionally, copper is also easy to fabricate and has good durability, but its high thermal conductivity is the main reason for its use in refrigeration systems.

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  • 5. 

    AS AN RMO IN CHARGE, YOU ARE REQUESTED TO REPLACE THE GAUGE ON THE HIGH SIDE OF THE REFRIGERATION SYSTEM.  THE PRESSURE GRADUATION RATE SHOULD BE

    • 1.2 OF DESIGN PRESSURE (AT LEAST)

    • THE RUPTURE GUARD HAS TO BE REPLACED ALSO

    • THE GAUGE HAS TO BE A COMPOUND GAUGE

    • THE GAUGE SHOULD BE GRADUATED TO PRESSURE

    Correct Answer
    A. 1.2 OF DESIGN PRESSURE (AT LEAST)
    Explanation
    The correct answer is 1.2 OF DESIGN PRESSURE (AT LEAST). This means that the pressure graduation rate of the new gauge should be at least 1.2 times the design pressure of the refrigeration system. This ensures that the gauge can accurately measure the pressure within the system and can handle the maximum pressure that the system is designed for. By replacing the gauge with one that meets this requirement, the RMO in charge can ensure the safe and efficient operation of the refrigeration system.

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  • 6. 

    YOU ARE AN RMO ASSIGNED TO FACILITY WHERE A REFRIGERANT HAS BEEN RECENTLY CHANGED FROM A FLAMMABLE REFRIGERANT TO R-22, AT THE MOMENT YOU ARE PLANNING TO BRAZE METAL.  ON SUCH MAKING A REPAIR IN THE MACHINERY ROOM, UNDER THESE CIRCUMSTANCES YOU:

    • MUST ENSURE THE FLAME IS ENCLOSED AND VENTED TO OPEN AIR

    • MAY MAKE REPAIRS AT LEAST 25 FEET FROM THE REFRIGERANT UNIT

    • MAY MAKE REPAIRS WITHOUT ANY RESTRICTIONS IF THE REFRIGERATING UNIT IS SHUT DOWN

    • MAY NOT MAKE REPAIR UNDER ANY CIRCUMSTANCES

    Correct Answer
    A. MUST ENSURE THE FLAME IS ENCLOSED AND VENTED TO OPEN AIR
    Explanation
    When working in a facility where the refrigerant has been changed to R-22, it is important to ensure safety when brazing metal. The correct answer states that the flame must be enclosed and vented to open air. This means that any flame used during the repair process should be contained within a safe enclosure and any fumes or gases produced should be vented to the open air. This is crucial to prevent any potential ignition or release of flammable gases that may be present due to the change in refrigerant. It prioritizes safety and minimizes the risk of accidents or hazards.

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  • 7. 

    WHEN INSTALLING A SERVICE VALVE TO ISOLATE A DUAL PRESSURE DEVICE WHILE KEEPING SYSTEM IN SERVICE, YOU WOULD USE A 

    • TWO WAY VALVE

    • THREE WAY VALVE

    • PLUG VALVE

    • STOP VALVE

    Correct Answer
    A. THREE WAY VALVE
    Explanation
    When installing a service valve to isolate a dual pressure device while keeping the system in service, a three-way valve would be used. A three-way valve has three ports, allowing for the diversion of flow between two different paths. In this case, the three-way valve would be able to redirect the flow from the dual pressure device to either the system or to a bypass line, effectively isolating the device without interrupting the system's operation.

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  • 8. 

    WHY IS SPRING LOADED PRV BETTER TO USE THAN A FUSIBLE PLUG?

    • LESS EXPENSIVE

    • EASY AVAILABILITY

    • FUSIBLE PLUG CANNOT RESET

    • LARGER

    Correct Answer
    A. FUSIBLE PLUG CANNOT RESET
    Explanation
    The reason why a spring-loaded PRV (Pressure Relief Valve) is better to use than a fusible plug is that the fusible plug cannot reset. Once the fusible plug melts and releases pressure, it cannot be reused or reset. On the other hand, a spring-loaded PRV can be reset after it has relieved pressure, making it more convenient and cost-effective in the long run. Additionally, spring-loaded PRVs are generally easier to find and readily available compared to fusible plugs.

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  • 9. 

    WHEN INSTALLING A PIPELINE AND YOU NEED TO MAKE A 90° ELBOW, WHICH IS THE BEST WAY?

    • BEND PIPE

    • USE FACTORY MADE 90° ELBOW AND BRAZE

    • USE FLEXIBLE TUBING

    • USE TWO 45° ELBOWS

    Correct Answer
    A. USE FACTORY MADE 90° ELBOW AND BRAZE
    Explanation
    Using a factory-made 90° elbow and brazing is the best way to make a 90° elbow when installing a pipeline. This method ensures a secure and reliable connection between the pipes, as the factory-made elbow is designed specifically for this purpose. Brazing helps to create a strong joint between the elbow and the pipes, ensuring that it can withstand the pressure and flow of the fluid or gas passing through the pipeline. Using a factory-made elbow also saves time and effort compared to bending the pipe or using multiple 45° elbows.

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  • 10. 

    SEMI-HERMETIC COMPRESSORS MAY BE BETTER TO USE THAN HERMETIC COMPRESSORS BECAUSE HERMETIC COMPRESSORS:

    • ARE FULLY ENCLOSED AND CANNOT BE SERVICED ON SITE

    • ARE EASIER TO GET TO

    • ARE MORE DIFFICULT TO GET TO

    • ARE MORE EXPENSIVE

    Correct Answer
    A. ARE FULLY ENCLOSED AND CANNOT BE SERVICED ON SITE
    Explanation
    Semi-hermetic compressors may be better to use than hermetic compressors because hermetic compressors are fully enclosed and cannot be serviced on site. This means that if there is any issue or maintenance required, the entire compressor unit needs to be replaced, which can be time-consuming and costly. In contrast, semi-hermetic compressors can be serviced on site, allowing for easier maintenance and potentially reducing downtime and costs.

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  • 11. 

    WHAT SAFETY GROUP DOES AMMONIA BELONG?

    • GROUP 2, B2

    • GROUP 1, A1

    • GROUP 3, B1

    • BOTH A1 AND B1

    Correct Answer
    A. GROUP 2, B2
    Explanation
    Ammonia belongs to Safety Group 2, B2. This classification indicates that ammonia is a hazardous substance, but with proper handling and precautions, it can be safely used. The B2 designation suggests that ammonia is a flammable gas, which means it can ignite and burn in certain conditions. It is important to follow safety protocols and guidelines when working with ammonia to prevent accidents and ensure the well-being of individuals and the environment.

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  • 12. 

    WHEN CHANGING WATER TO ICE, WHAT MUST BE REMOVED?

    • SPECIFIC HEAT

    • SUPER HEAT

    • LATENT HEAT

    • SENSIBLE HEAT

    Correct Answer
    A. LATENT HEAT
    Explanation
    When changing water to ice, latent heat must be removed. Latent heat is the heat energy required to change the state of a substance without changing its temperature. In the case of water, when it is cooled below its freezing point, the latent heat must be removed in order for it to solidify and become ice. This heat energy is used to break the intermolecular bonds between water molecules, allowing them to arrange themselves in a solid crystalline structure.

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  • 13. 

    A MOTOR HAS 4 BELTS, THE CENTER BELT IS WORN, YOU WOULD

    • CHANGE THE CENTER BELT

    • CHANGE CENTER BELT AND ALL OTHER BELTS

    • CHANGE THE OTHER BELTS

    • CHANGE TO DIRECT DRIVE SYSTEM

    Correct Answer
    A. CHANGE CENTER BELT AND ALL OTHER BELTS
    Explanation
    The correct answer is to change the center belt and all other belts. This is because if the center belt is worn, it is likely that the other belts are also worn and may need to be replaced. Changing all the belts ensures that the motor will function properly and reduces the risk of any further belt-related issues.

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  • 14. 

    OF THE FOLLOWING CHARACTERISTICS OF REFRIGERANT, THE ONE THAT BEST DESCRIBES REFRIGERANT 22 IS:

    • ODORLESS WHEN MIXED WITH AIR

    • AN ETHER LIKE ODOR WHEN MIXED WITH AIR

    • EXPLOSIVE WHEN MIXED WITH AIR

    • BOILS AT HIGHER TEMP THAT R-12

    Correct Answer
    A. ODORLESS WHEN MIXED WITH AIR
    Explanation
    Refrigerant 22 is described as odorless when mixed with air. This means that it does not have a distinct smell when it is in the air.

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  • 15. 

    ACCORDING TO NYC FIRE CODE CLASSIFICATION OF REFRIGERANT, AMMONIA WOULD FALL UNDER WHICH GROUP?

    • GROUP 1

    • GROUP 2

    • GROUP 3

    • GROUP 4

    Correct Answer
    A. GROUP 2
    Explanation
    Ammonia would fall under Group 2 according to the NYC Fire Code classification of refrigerant. This means that it is classified as a moderately hazardous material.

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  • 16. 

    OF THE FOLLOWING, WHICH REFRIGERANT REQUIRES THE APPROVAL FOR USE BY THE NYC FIRE DEPT?

    • R-22

    • R-12

    • CARBON DIOXIDE

    • BUTANE

    Correct Answer
    A. BUTANE
    Explanation
    Butane is the correct answer because it is a flammable refrigerant that requires approval for use by the NYC Fire Department. R-22 and R-12 are both commonly used refrigerants but do not require special approval. Carbon dioxide is a non-flammable refrigerant and also does not require approval.

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  • 17. 

    ACCORDING TO THE SAFETY HAND BOOK, HOW MUCH REFRIGERANT CAN BE RECOVERED INTO A 60 LB CONTAINER?

    • 60 LBS

    • 45 LBS

    • 30 LBS

    • 15 LBS

    Correct Answer
    A. 45 LBS
    Explanation
    According to the safety handbook, a 60 lb container can recover up to 45 lbs of refrigerant.

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  • 18. 

    WHAT REFRIGERANT SYSTEMS ARE MOST LIKELY TO LEAK REFRIGERANT IN BUILDING SPACES THAT ARE BEING COOLED?

    • INDIRECT SYSTEMS

    • DIRECT SYSTEMS

    • INDIRECT CLOSED SYSTEMS

    • INDRIECT OPEN SYSTEMS

    Correct Answer
    A. DIRECT SYSTEMS
    Explanation
    Direct systems are most likely to leak refrigerant in building spaces that are being cooled. This is because direct systems have direct contact between the refrigerant and the building space being cooled, which increases the chances of leaks occurring. In contrast, indirect systems have a separate closed loop for the refrigerant, reducing the likelihood of leaks.

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  • 19. 

    WHEN CHARGING AN R-12 RECIPROCATING REFRIGERATION SYSTEM, AN OPERATOR WOULD WANT TO USE WARM WATER TO INCREASE THE RELEASE RATE OF REFRIGERANT FROM THE DRUM.  TO PERFORM THIS OPERATION THE WATER TEMP. SHOULD NOT EXCEED THE DEGREE °F OF

    • 80°F

    • 90°F

    • 110°F

    • 130°F

    Correct Answer
    A. 90°F
    Explanation
    When charging an R-12 reciprocating refrigeration system, using warm water can increase the release rate of refrigerant from the drum. However, the water temperature should not exceed 90°F. If the water temperature is too high, it can cause the refrigerant to vaporize too quickly, leading to unstable charging and potential damage to the system. Therefore, it is important to use warm water within the specified temperature range to ensure safe and effective charging of the system.

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  • 20. 

    IN A REFRIGERATION PLANT, A SMALL INDUCTION REFRIGERATION MOTOR IS RUNNING ON AC CURRENT.  IN ORDER FOR THE OPERATOR TO DETERMINE THE TRUE POWER CONSUMPTION, ASSUMING THAT IF EVERY ELIGIBLE CHARACTERISTICS HAVE BEEN MEANT, OF THE FOLLOWING THE POWER CONSUMPTION IS DETERMINED BY THE APPLICATION OF THE FORMULA:

    • WATTS = VOLTS X AMPS X OHMS

    • WATTS = VOLTS X AMPS X HERTZ

    • WATTS = VOLTS X AMPS

    • WATTS = VOLTS X AMPS X POWER FACTOR

    Correct Answer
    A. WATTS = VOLTS X AMPS X POWER FACTOR
    Explanation
    The correct answer is WATTS = VOLTS X AMPS X POWER FACTOR. This formula is used to determine the true power consumption in a refrigeration plant when a small induction refrigeration motor is running on AC current. The power consumption is calculated by multiplying the voltage, current, and power factor. The power factor takes into account the phase difference between the voltage and current waveforms and represents the efficiency of the motor in converting electrical power into useful work. Therefore, including the power factor in the formula provides a more accurate measurement of the true power consumption.

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  • 21. 

    IN AN EMERGENCY IF YOU MUST DUMP REFRIGERANT INTO SEWER, YOU WILL DUMP ONLY WHEN

    • SEWER IS NOT CONNECTED TO A STORM DRAIN

    • FIRST CONFIRM THAT REFRIGERANT IS NOT FLAMMABLE

    • FACILITY MANAGER APPROVES IT

    • YOU DISCHARGE UNDER THE SUPERVISION OF THE FIRE DEPT.

    Correct Answer
    A. YOU DISCHARGE UNDER THE SUPERVISION OF THE FIRE DEPT.
    Explanation
    The correct answer is "YOU DISCHARGE UNDER THE SUPERVISION OF THE FIRE DEPT." because in an emergency situation where refrigerant needs to be dumped into the sewer, it is important to ensure that proper safety measures are followed. Discharging under the supervision of the fire department ensures that the process is carried out in a controlled manner, minimizing the risk of harm to the environment and individuals. The fire department can provide guidance and oversight to ensure that the disposal is done safely and in compliance with regulations.

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  • 22. 

    WHAT IS PURPOSE OF HAVING A SERVICE VALVE STEM CAP?

    • TO PROTECT FROM BEING INADVERTENTLY TURNED FROM ITS POSITION AND FROM BEING DAMAGED

    • TO LET YOU KNOW THE POSITION OF THE VALVE

    • TO LET YOU NOTICE VALVE FROM A DISTANCE

    • TO CAP OFF VALVE SO THAT UT CAN NEVER BE USED

    Correct Answer
    A. TO PROTECT FROM BEING INADVERTENTLY TURNED FROM ITS POSITION AND FROM BEING DAMAGED
    Explanation
    The purpose of having a service valve stem cap is to protect the valve from being inadvertently turned from its position and from being damaged. The cap acts as a protective cover that prevents any accidental movement or tampering of the valve, ensuring that it remains in its intended position. Additionally, the cap also provides a layer of protection against external elements that could potentially cause damage to the valve, such as dirt, debris, or moisture.

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  • 23. 

    WHICH OF THE FOLLOWING ASHRAE SAFETY GROUPS IS THE MOST DANGEROUS?

    • A1

    • A2

    • B2

    • B3

    Correct Answer
    A. B3
    Explanation
    The correct answer is B3. This implies that among the given options, the ASHRAE Safety Group B3 is the most dangerous. However, without further information, it is not possible to provide a specific explanation as to why B3 is considered the most dangerous.

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  • 24. 

    BECAUSE OF THE LATENT HEAT LOAD, REFRIGERATION MACHINE OPERATOR WAS INSTRUCTED TO START THE RECIPROCATING PLANT FOR AIR CONDITIONING.  OF THE FOLLOWING ACCORDING TO RECOMMENDED PRACTICE, THE FIRST THING TO DO IS

    • TURN ON CHILLED WATER PUMPS AND OPEN THE BYPASS TO LIGHTER LOAD

    • INSTALL LARGER FUSE TO TAKE THE INITIAL LOAD, AND THEN TURN ON THE COOLING TOWER FANS

    • TURN ON CHILLED WATER PUMP, CONDENSER WATER PUMPS AND COOLING TOWER FANS

    • SET THE THERMOSTAT A FEW DEGREES HIGHER

    Correct Answer
    A. TURN ON CHILLED WATER PUMP, CONDENSER WATER PUMPS AND COOLING TOWER FANS
    Explanation
    The correct answer is to turn on the chilled water pump, condenser water pumps, and cooling tower fans. This is because the latent heat load requires the refrigeration machine operator to start the reciprocating plant for air conditioning. To effectively handle this load, it is necessary to ensure the proper circulation of chilled water, condenser water, and cooling tower air. Therefore, turning on the chilled water pump, condenser water pumps, and cooling tower fans is the recommended practice to address the latent heat load.

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  • 25. 

    AN AUTOMATIC PURGE UNIT IS REQUIRED FOR THOSE REFRIGERATING SYSTEMS THAT HAVE

    • DOUBLE INDIRECT OPEN SPACE SYSTEMS

    • SYSTEMS OPERATING BELOW ATMOSPHERIC PRESSURE

    • ABSORPTION COMPRESSORS

    • OUTSIDE AIR DAMPERS

    Correct Answer
    A. SYSTEMS OPERATING BELOW ATMOSPHERIC PRESSURE
    Explanation
    An automatic purge unit is required for refrigerating systems operating below atmospheric pressure. This is because when a system operates below atmospheric pressure, there is a higher likelihood of air and moisture entering the system. The automatic purge unit helps to remove any air and moisture that may have entered the system, ensuring the system operates efficiently and effectively.

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  • 26. 

    A RMO WOULD EXPECT A RELIEF VALVE TO START FUNCTIONING (FOR THE SECTION OF REFRIGERATING SYSTEM BEING PROTECTED) AT A PRESSURE MOST CLOSEST TO:

    • 5% OVER DESIGN PRESSURE

    • THE DESIGN PRESSURE

    • RECOMMENDED OPERATING PRESSURE FOR NORMAL COOLING CONDITIONS

    • 20% BELOW DESIGN PRESSURE

    Correct Answer
    A. THE DESIGN PRESSURE
    Explanation
    A relief valve is designed to protect a refrigerating system from excessive pressure. It is set to open and release the excess pressure when it reaches a certain threshold. The design pressure is the maximum pressure that the system is designed to safely handle. Therefore, a RMO (Refrigeration Maintenance Operator) would expect the relief valve to start functioning at the design pressure, as this is the point where the system is at risk of being damaged or compromised.

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  • 27. 

    AN RMO NOTICES A KNOCKING RECIPROCATING COMPRESSOR.  THE RMO IS ASSURED THE COMPRESSOR HAS NO WORN PARTS.  THE MOST PROBABLE CAUSE OF THE KNOCKING IS:

    • INADEQUATE LUBRICATION

    • LIQUID SLUGGING

    • CRANKCASE PRESSURE TO LOW

    • SUCTION AND DISCHARGE NOT OPENING AND CLOSING

    Correct Answer
    A. LIQUID SLUGGING
    Explanation
    The most probable cause of the knocking in the reciprocating compressor is liquid slugging. Liquid slugging occurs when liquid refrigerant enters the compressor, causing damage to the internal components and resulting in knocking or banging noises. This can happen due to factors such as improper refrigerant charge, liquid refrigerant entering the suction line, or a malfunctioning expansion valve. It is important to address this issue promptly to prevent further damage to the compressor.

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  • 28. 

    AN OPERATOR HAS BEEN ASSIGNED TO RUN A CENTRIFUGAL COMPRESSOR.  OF THE FOLLOWING ACTIONS A CAPACITY CONTROL IS MOST LIKELY TO ACHIEVE IS THROUGH

    • BYPASS DISCHARGE GAS

    • ADJUSTMENT OF THE IMPELLER INLET GUIDE PRE-ROTATION VANES

    • CONDENSER PRESSURE VARIATION

    • ADDING RE-EXPANSION VOLUME

    Correct Answer
    A. ADJUSTMENT OF THE IMPELLER INLET GUIDE PRE-ROTATION VANES
    Explanation
    Adjustment of the impeller inlet guide pre-rotation vanes is most likely to achieve capacity control in a centrifugal compressor. By adjusting the vanes, the flow of gas into the impeller can be controlled, thereby affecting the compressor's capacity. This allows the operator to regulate the amount of gas being compressed, ensuring that the compressor operates at the desired capacity. Bypass discharge gas, condenser pressure variation, and adding re-expansion volume may have other functions in a centrifugal compressor system, but they are not specifically related to capacity control.

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  • 29. 

    Is [your statement here] true or false?

    • True

    • False

    Correct Answer
    A. True
    Explanation
    The given correct answer is true.

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  • 30. 

    AN OPERATOR HAS BEEN ASSIGNED TO RUN  A RECIPROCATING COMPRESSOR.  THE FOLLOWING ACTION CAPACITY CONTROL WOULD MOST LIKELY BE ACHIEVED THROUGH:

    • OPENING THE SUCTION VALVES WITH SOME FORM OF CONTROL

    • CONTROLLING THE DISCHARGE PRESSURE

    • CHANGING THE STROKE AND ADDING RE-EXPANSION VOLUME

    • RETURNING THE DISCHARGE GAS TO SUCTION

    Correct Answer
    A. OPENING THE SUCTION VALVES WITH SOME FORM OF CONTROL
    Explanation
    The action of capacity control in a reciprocating compressor is most likely achieved by opening the suction valves with some form of control. By adjusting the opening of the suction valves, the amount of gas entering the compressor can be controlled, thus regulating the capacity of the compressor. This allows for flexibility in matching the compressor's output to the required demand, ensuring efficient operation.

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  • 31. 

    R-11 AND R-123 REFRIGERANTS ARE

    • OXYGEN DEPLETING

    • HEAVIER THAN AIR

    • ARE CLASS-1 AND CLASS-2 SUBSTANCES DEFINED BY EPA

    • ALL OF THE ABOVE

    Correct Answer
    A. ALL OF THE ABOVE
    Explanation
    The correct answer is "ALL OF THE ABOVE". R-11 and R-123 refrigerants are known to be oxygen depleting, meaning they can reduce the amount of oxygen available in an area. They are also heavier than air, which means they tend to sink and accumulate in low-lying areas. Additionally, R-11 and R-123 are classified as Class-1 and Class-2 substances by the Environmental Protection Agency (EPA), indicating that they are considered to be potentially harmful to human health and the environment.

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  • 32. 

    WHAT IS THE TEV DIApHRAM MADE OF

    • RUBBER

    • METAL

    • PLASTIC

    • GRAPHITE

    Correct Answer
    A. METAL
    Explanation
    The explanation for the correct answer, METAL, is that the TEV diaphragm is typically made of a flexible metal material. This is because a metal diaphragm provides better durability and resistance to high pressures and temperatures compared to other materials like rubber, plastic, or graphite. The metal diaphragm also ensures a more accurate and reliable operation of the TEV, which is essential for regulating the flow of refrigerant in cooling systems.

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  • 33. 

    IF YOU JUST PURCHASED A THERMOMETER AND NEED TO CHECK TO SEE IF ITS WORKING PROPERLY, HOW WOULD YOU DO IT?

    • TOUCH IT IN A POT OF BOILING WATER

    • TOUCH IT TO BUCKET OF ICE / ICE WATER

    • COMPARE TO 2 OTHER THERMOMETERS

    • COMPARE TO ANOTHER RMO THERMOMETER

    Correct Answer
    A. TOUCH IT TO BUCKET OF ICE / ICE WATER
    Explanation
    To check if a newly purchased thermometer is working properly, you can touch it to a bucket of ice or ice water. This is because the melting point of ice is known to be 0 degrees Celsius or 32 degrees Fahrenheit. By placing the thermometer in the ice water, you can verify if it accurately reads this temperature. If the thermometer displays a different reading, it may indicate a malfunction or calibration issue. Comparing it to other thermometers or an RMO thermometer can also be helpful in determining its accuracy.

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  • 34. 

    THE ADVANTAGE OF FORCED DRAFT OVER NATURAL DRAFT COOLING TOWER IS:

    • THE POSSIBILITY OF LOWER WATER OUT TEMP

    • THERE IS NO DEPENDENCE ON NATURAL WIND VELOCITY

    • USE OF A SMALLER TOWER SIZE

    • ALL OF THE ABOVE

    Correct Answer
    A. ALL OF THE ABOVE
    Explanation
    Forced draft cooling towers have the advantage of lower water outlet temperature compared to natural draft cooling towers. This is because forced draft towers use fans to force air through the tower, resulting in better heat transfer and lower water temperatures. Additionally, forced draft towers are not dependent on natural wind velocity, allowing for more consistent cooling performance. Lastly, the use of fans in forced draft towers allows for a smaller tower size, making them more space-efficient. Therefore, all of the above statements are advantages of forced draft over natural draft cooling towers.

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  • 35. 

    WITH RESPECT TO FIRE SAFETY, THE ANSI/ASHRAE REFRIGERANT SAFETY CLASSIFICATION THAT IS MOST DANGEROUS IS

    • A1

    • B2

    • A3

    • B1

    Correct Answer
    A. A3
    Explanation
    The correct answer is A3. In terms of fire safety, the ANSI/ASHRAE refrigerant safety classification that is most dangerous is A3. Refrigerants classified as A3 are highly flammable and can pose a significant fire hazard if not handled properly. It is important to take appropriate precautions and follow safety guidelines when working with A3 refrigerants to minimize the risk of fire accidents.

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  • 36. 

    A PUMP AFFECTS THE PRESSURE OF A FLUID OR GAS BY: 

    • REDUCING PRESSURE

    • RAISING PRESSURE

    • REGULATING PRESSURE

    • STABILIZING PRESSURE

    Correct Answer
    A. RAISING PRESSURE
    Explanation
    A pump affects the pressure of a fluid or gas by raising the pressure. When a pump is used, it applies force to the fluid or gas, increasing its pressure. This is typically done by increasing the velocity of the fluid or gas and then converting that velocity into pressure. As a result, the pressure of the fluid or gas is raised, allowing it to flow or be used in various applications.

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  • 37. 

    A RMO NEEDED TO VARY THE FLOW OF REFRIGERANT IN A SYSTEM.  A CONTINUOUS VARIATION IN THE FLOW OF THE SYSTEM DOES NOT INCLUDE THE:

    • SOLENOID VALVE

    • HIGH SIDE FLOAT

    • THERMAL EXPANSION VALVE

    • CAPILLARY TUBE

    Correct Answer
    A. SOLENOID VALVE
    Explanation
    The solenoid valve is not capable of providing a continuous variation in the flow of refrigerant in a system. It can only be either fully open or fully closed, resulting in a binary on/off flow. Therefore, it is not included in the options for a continuous variation in flow.

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  • 38. 

    WHEN PROPERLY PURGING YOU SHOULD

    • PURGE AT RAPID RATE

    • PURGE WITH COMPRESSOR ON

    • STOP WHEN PRESSURE CEASES TO DROP

    • RUN THE CONDENSER AS MUCH AS POSSIBLE

    Correct Answer
    A. STOP WHEN PRESSURE CEASES TO DROP
    Explanation
    When properly purging, you should stop when the pressure ceases to drop. This means that all the unwanted gases or contaminants have been successfully removed from the system. Continuing to purge beyond this point would be unnecessary and a waste of time and resources.

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  • 39. 

    GIVEN A REFRIGERATION SYSTEM WHICH INCLUDES A FORCED DRAFT COOLING TOWER, AN ECONOMIZER AND CHILLED WATER AS THE COOLING MEDIUM, THE HEAT THAT IS REMOVED FROM THE BUILDING IS FINALLY REJECTED:

    • AS HEAT OF EVAPORATION OF THE COOLING TOWER

    • IN THE ECONOMIZER

    • IN THE EVAPORATOR

    • CONDENSER WATER OUTLET

    Correct Answer
    A. AS HEAT OF EVAPORATION OF THE COOLING TOWER
    Explanation
    The correct answer is "AS HEAT OF EVAPORATION OF THE COOLING TOWER". In a refrigeration system with a forced draft cooling tower, the cooling tower removes heat from the building by evaporating water. As the water evaporates, it absorbs heat from the building, effectively cooling it down. This heat is then rejected into the atmosphere, making the heat of evaporation of the cooling tower the final destination for the heat removed from the building.

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  • 40. 

    WHICH IS NOT USED AS A COOLING MEDIUM IN AN INDIRECT SYSTEM

    • R-22

    • CALCIUM CHLORIDE

    • GLOCOL

    • SODIUM CHLORIDE

    Correct Answer
    A. R-22
    Explanation
    R-22 is not used as a cooling medium in an indirect system. R-22 is a hydrochlorofluorocarbon (HCFC) refrigerant that was commonly used in air conditioning and refrigeration systems. However, due to its harmful effects on the ozone layer, its production and use have been phased out in many countries. In indirect cooling systems, other cooling mediums such as calcium chloride, glycol, or sodium chloride are used instead.

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  • 41. 

    MACHINE ROOM SAFETY STANDARDS HAVE BEEN ESTABLISHED BY

    • ARI-700

    • ARI-740

    • ASHRAE 34

    • ASHRAE 15

    Correct Answer
    A. ASHRAE 15
    Explanation
    ASHRAE 15 is the correct answer because it is a standard developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) specifically for safety requirements in refrigeration systems. It provides guidelines and regulations for the design, construction, installation, and operation of refrigeration systems to ensure the safety of personnel working in machine rooms. ARI-700 and ARI-740 are not related to machine room safety, and while ASHRAE 34 is a standard for refrigerant classification, it does not specifically address machine room safety.

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  • 42. 

    ONE DISADVANTAGE IN USING BRINES AS A COOLING MEDIUM IS CORROSION.  IN COMMERCIAL PRACTICE CORROSION AND THE AMOUNT OF RUST FORMED IS REDUCED BY THE ADDITION TO THE BRINE SOLUTION OF:

    • WEAK ACID SOLUTION

    • ZINC COMPOUNDS

    • GLYCOLS

    • DI-CHROMATES

    Correct Answer
    A. DI-CHROMATES
    Explanation
    The use of di-chromates in brine solutions helps to reduce corrosion and the formation of rust. Di-chromates have anti-corrosive properties and can form a protective layer on metal surfaces, preventing them from coming into contact with the brine solution and reducing the likelihood of corrosion. This makes di-chromates an effective additive for maintaining the integrity and longevity of cooling systems that use brines as a cooling medium.

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  • 43. 

    WHICH TYPE OF PUMP IS CONSIDERED A NON-POSITIVE DISPLACEMENT PUMP?

    • RECIPROCATING

    • ROTORY, SCREW

    • SCROLL

    • CENTRIFUGAL

    Correct Answer
    A. CENTRIFUGAL
    Explanation
    A centrifugal pump is considered a non-positive displacement pump because it uses centrifugal force to move fluid rather than trapping and displacing a fixed amount of fluid with each rotation, like positive displacement pumps do. Instead, a centrifugal pump uses an impeller to spin the fluid, creating a centrifugal force that pushes the fluid outward. This design allows for a continuous flow of fluid, making it more suitable for applications where a constant flow rate is required.

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  • 44. 

    DUE TO A COLD FRONT, THERE WAS A SHARP DROP IN O.A.T., THE MOST LIKELY EFFECT OF THIS CONDITION ON THE OPERATION OF THE RECIPROCATING MACHINE WOULD BE THAT THE THERMOSTAT CAUSES SOLENOID VALVE TO:

    • CLOSE, THE COMPRESSOR PUMPS DOWN AND SHUTS DOWN ON LOW PRESSURE

    • CLOSE AND THE COMPRESSOR WILL START ON HIGH PRESSURE

    • OPEN AND COMPRESSOR WILL PUMP DOWN AND GO OFF ON HIGH PRESSURE

    • OPEN AND COMPRESSOR WILL CONTINUE TO RUN AT REDUCED SPEED

    Correct Answer
    A. CLOSE, THE COMPRESSOR PUMPS DOWN AND SHUTS DOWN ON LOW PRESSURE
    Explanation
    The cold front caused a sharp drop in outside air temperature (O.A.T.), which would activate the thermostat. In response, the thermostat would cause the solenoid valve to close. As a result, the compressor would pump down and shut down due to low pressure. This is the most likely effect because when the solenoid valve closes, it restricts the flow of refrigerant, causing the compressor to pump down and reach low pressure, leading to a shutdown.

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  • 45. 

    OF THE FOLLOWING THE MOST COMMON METERING DEVICE USED TODAY IN A RECIPROCATING COMMERCIAL REFRIGERATION SYSTEM OVER 3 TONS IS

    • AUTOMATIC EXPANSION VALVE

    • THERMOSTATIC EXPANSION VALVE

    • LOW SIDE FLOAT

    • HIGH SIDE FLOAT

    Correct Answer
    A. THERMOSTATIC EXPANSION VALVE
    Explanation
    The most common metering device used today in a reciprocating commercial refrigeration system over 3 tons is the thermostatic expansion valve. This valve is designed to control the flow of refrigerant into the evaporator based on the temperature and pressure conditions. It ensures that the right amount of refrigerant is supplied to the evaporator to maintain optimum cooling efficiency. The thermostatic expansion valve is preferred over other options like automatic expansion valve, low side float, and high side float due to its ability to provide precise control and better performance in a wide range of operating conditions.

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  • 46. 

    IF YOU WERE RUNNING THREE COMPRESSORS, WHICH BEST DESCRIBES THE STATE OF REFRIGERANT LEAVING THE THIRD COMPRESSOR?

    • MOSTLY LIQUID, SOME VAPOR

    • MOSTLY VAPOR, SOME LIQUID

    • SLIGHTLY SUPERHEATED VAPOR

    • HIGHLY SUPERHEATED VAPOR

    Correct Answer
    A. HIGHLY SUPERHEATED VAPOR
    Explanation
    When running three compressors, the refrigerant leaving the third compressor would be in a highly superheated vapor state. This means that the refrigerant has been heated above its saturation temperature, resulting in a gas-like state with no liquid present. Superheating occurs when the refrigerant absorbs additional heat after it has completely evaporated, leading to an increase in temperature. In this case, the refrigerant leaving the third compressor has undergone significant superheating, indicating that it is mostly in a vapor form with very little or no liquid content.

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  • 47. 

    THE AMOUNT OF REFRIGERANT THAT FLOWS THROUGH THE ORIFICE PLATE IS DETERMINED BY:

    • THE NUMBER OF ECONOMIZER STAGES

    • THE NUMBER OF COMPRESSION STAGES

    • TEMPERATURE OF REFRIGERANT IN THE HIGH SIDE

    • DIFFERENCE IN PRESSURE BETWEEN HIGH AND LOW SIDES

    Correct Answer
    A. DIFFERENCE IN PRESSURE BETWEEN HIGH AND LOW SIDES
    Explanation
    The amount of refrigerant that flows through the orifice plate is determined by the difference in pressure between the high and low sides. This is because the pressure difference creates a pressure drop across the orifice plate, which in turn controls the flow rate of the refrigerant. The higher the pressure difference, the greater the flow rate of the refrigerant through the orifice plate. Conversely, a lower pressure difference will result in a lower flow rate of refrigerant. The number of economizer stages, the number of compression stages, and the temperature of the refrigerant in the high side do not directly affect the flow rate of the refrigerant through the orifice plate.

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  • 48. 

    HOW MANY BTUs WOULD BE REMOVED IN A 30 TON SYSTEM?

    • 12,000 PER HOUR

    • 360,000 PER MINUTE

    • 12,000 PER MINUTE

    • 360,000 PER HOUR

    Correct Answer
    A. 360,000 PER HOUR
    Explanation
    In a 30 ton system, the correct answer is 360,000 BTUs per hour. This means that the system has the capacity to remove 360,000 BTUs of heat energy from the space it is cooling every hour. The other options, such as 12,000 BTUs per hour or 360,000 BTUs per minute, are not correct as they do not accurately represent the capacity of a 30 ton system.

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  • 49. 

    IF AN ELECTRIC MOTOR IS REWOUND TO CUT RESISTANCE BY 1/2, ALL OTHER FACTORS BEING EQUAL, THE MOTOR POWER WOULD:

    • REDUCE BY 1/2

    • INCREASE BY A FACTOR OF 2

    • STAY THE SAME

    • INCREASE BY A FACTOR OF 4

    Correct Answer
    A. INCREASE BY A FACTOR OF 2
    Explanation
    When an electric motor is rewound to cut resistance by 1/2, it means that the resistance in the motor circuit has been reduced. Since power is directly proportional to the square of the current and inversely proportional to the resistance, reducing the resistance by 1/2 will result in a doubling of the current. As a result, the power of the motor will increase by a factor of 2.

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Quiz Review Timeline (Updated): Apr 15, 2024 +

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  • Current Version
  • Apr 15, 2024
    Quiz Edited by
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  • Mar 01, 2019
    Quiz Created by
    Popemountvernon

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