Refrigerant Machine Operator Trivia Test #2

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  • 1/100 Questions

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

    • EASY FABRICATION
    • EASY DURABILITY
    • HIGH THERMAL CONDUCTIVITY
    • FLEXIBILITY
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Refrigerant Machine Operator Trivia Test #2 - Quiz
About This Quiz

Dive into the REFRIGERANT MACHINE OPERATOR Trivia TEST #2, designed to assess key skills in handling and operating refrigerant systems. This quiz evaluates knowledge on refrigerant characteristics, system operations, and safety practices, essential for professionals in HVAC and refrigeration.

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  • 2. 

    WHAT IS A METHOD USED TO CALIBRATE A THERMOMETER?

    • PLACE THERMOMETER IN CUP OF ICE

    • PLACE THERMOMETER IN SUPERHEATED STEAM

    • LOWER TEMPERATURE ON THERMOMETER

    • RAISE TEMPERATURE ON THERMOMETER

    Correct Answer
    A. PLACE THERMOMETER IN CUP OF ICE
    Explanation
    Placing the thermometer in a cup of ice is a method used to calibrate a thermometer because ice has a known temperature of 0 degrees Celsius or 32 degrees Fahrenheit. By placing the thermometer in the ice, it allows the thermometer to adjust to the temperature of the ice and ensures that it is accurately measuring the temperature. This method helps to verify the accuracy of the thermometer and allows for any necessary adjustments to be made.

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  • 3. 

    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 best described as odorless when mixed with air. This means that when Refrigerant 22 is released into the air and mixed with it, it does not produce any distinct smell. This characteristic is important for safety reasons, as an odorless refrigerant can be difficult to detect in case of a leak or release. It is crucial to be aware of the characteristics of refrigerants to ensure proper handling and maintenance of refrigeration systems.

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  • 4. 

    WHEN DRY BULB IS 75°F AND WET BULB IS 75°F:

    • NOT POSSIBLE

    • VERY LOW HUMIDITY

    • THERMOMETER IS DEFECTIVE

    • 100% RELATIVE HUMIDITY

    Correct Answer
    A. 100% RELATIVE HUMIDITY
    Explanation
    When the dry bulb temperature and wet bulb temperature are both 75°F, it indicates that the air is saturated with moisture and cannot hold any more water vapor. This means that the relative humidity is at its maximum level of 100%.

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  • 5. 

    WHAT REFRIGERANTS ARE YOU NOT ABLE TO DUMP?

    • CFC

    • HCFC

    • HFC

    • ANY REFRIGERANT CONTAINING CHLORINE OR FLUORINE

    Correct Answer
    A. ANY REFRIGERANT CONTAINING CHLORINE OR FLUORINE
    Explanation
    Refrigerants that contain chlorine or fluorine cannot be dumped. CFCs, HCFCs, and HFCs are all types of refrigerants that contain either chlorine or fluorine. These substances are harmful to the environment and contribute to ozone depletion and global warming. Therefore, it is important to properly dispose of refrigerants and not dump them into the environment.

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  • 6. 

    REGARDLESS OF SAFETY CLASSIFICATION OF THE REFRIGERANT IN USE, IN THE EVENT OF REFRIGERANT ESCAPE, THE RMO SHOULD BE AWARE OF:

    • A REFRIGERANT FIRE

    • REFRIGERANT POISONING

    • OXYGEN DEPRIVATION

    • ATMOSPHERIC SUPERHEATING

    Correct Answer
    A. OXYGEN DEPRIVATION
    Explanation
    In the event of a refrigerant escape, the RMO (Responsible Managing Officer) should be aware of oxygen deprivation. When a refrigerant escapes, it can displace the oxygen in the surrounding area, leading to a decrease in oxygen levels. This can be dangerous for anyone present in the area, as it can cause suffocation or other respiratory issues. Therefore, it is important for the RMO to be aware of this potential hazard and take appropriate measures to ensure the safety of individuals in the vicinity.

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  • 7. 

    WHEN OPERATING A RECIPROCATING REFRIGERATION SYSTEM WITH A BELT DRIVEN COMPRESSOR, AN RMO NOTICES THAT ONE OF THE 4 BELTS IS BROKEN.  OF THE FOLLOWING, THE MOST ADVISABLE COURSE OF ACTION FOR THE RMO WOULD BE TO

    • PUT MORE GREASE ON THE REMAINING BELTS

    • REPLACE ALL 4 BELTS WITH A NEW SET

    • REPLACE THE BROKEN BELT ONLY

    • OPERATE WITH THE 3 REMAINING BELTS

    Correct Answer
    A. REPLACE ALL 4 BELTS WITH A NEW SET
    Explanation
    When operating a reciprocating refrigeration system with a belt-driven compressor, if one of the four belts is broken, the most advisable course of action for the RMO would be to replace all four belts with a new set. This is because the belts work together to drive the compressor, and if one belt is broken, it indicates that the other belts may also be worn or damaged. By replacing all four belts, the RMO ensures that the system will continue to operate efficiently and effectively.

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  • 8. 

    WHEN YOU PLAN ON OVERHAULING A SYSTEM AND YOU HAVE RECOVERED ALL LIQUID REFRIGERANT, WHAT IS NEXT?

    • GO AHEAD AND DO THE WORK

    • RECOVER ALL VAPOR, THEN DO WORK

    • SEND LIQUID NITROGEN THROUGH

    • EVACUATE SYSTEM

    Correct Answer
    A. RECOVER ALL VAPOR, THEN DO WORK
    Explanation
    After recovering all the liquid refrigerant, the next step is to recover all the vapor before proceeding with the work. This is important to ensure that all the refrigerant is properly removed from the system, preventing any potential leaks or contamination. Once all the vapor is recovered, then the work can be safely carried out.

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  • 9. 

    A REFRIGERATION UNIT IS MEASURED IN:

    • WATTS

    • VOLTS

    • BTUs

    • TEMPERATURE

    Correct Answer
    A. BTUs
    Explanation
    A refrigeration unit is measured in BTUs (British Thermal Units). BTUs are a unit of measurement used to quantify the amount of heat energy required to raise the temperature of one pound of water by one degree Fahrenheit. In the context of a refrigeration unit, BTUs are used to measure the cooling capacity of the unit. The higher the BTU rating, the more cooling power the unit has. Watts and volts are units of measurement for electrical power, while temperature is a measure of the degree of hotness or coldness of an object or environment.

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  • 10. 

    IF HAD TO INSTALL A SOLENOID VALVE TO A SYSTEM WHICH USES 110 VOLTS AND NEEDED TO CONVERT IT TO 24 VOLTS, WHAT WOULD YOU USE?

    • STEP UP TRANSFORMER

    • STEP DOWN TRANSFORMER

    • AC TO DC RECTIFICATION

    • REWIRE CIRCUIT WITH SMALLER GAUGE WIRE

    Correct Answer
    A. STEP DOWN TRANSFORMER
    Explanation
    A step-down transformer is used to convert a higher voltage to a lower voltage. In this case, the system uses 110 volts and needs to be converted to 24 volts, so a step-down transformer would be the appropriate choice. This transformer would reduce the voltage from 110 volts to 24 volts, allowing the solenoid valve to operate safely and effectively within the system.

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  • 11. 

    COMPOUND GAUGES CAN MEASURE:

    • ABOVE ATMOSPHERIC

    • BELOW ATMOSPHERIC

    • TEMPERATURE

    • ALL OF THE ABOVE

    Correct Answer
    A. ALL OF THE ABOVE
    Explanation
    Compound gauges are capable of measuring pressure both above and below atmospheric pressure. They can also measure temperature. Therefore, the correct answer is "ALL OF THE ABOVE".

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  • 12. 

    THE REFRIGERATION UNIT WHICH YOU HAVE BEEN ASSIGNED TO IS BEING TAKEN OUT OF SERVICE FOR MAJOR REPAIRS.  YOU HAVE BEEN ASSIGNED TO WITHDRAW REFRIGERANT FOR STORAGE IN SUITABLE CONTAINERS.  ACCORDING TO THE NYC FIRE LAW HANDBOOK YOU MUST ENSURE THAT CONTAINERS:

    • ARE APPROVED BY THE U.S. DEPT. OF TRANSPORTATION

    • ARE APPROVED BY THE FACILITIES MANAGER

    • DO NOT WEIGH MORE THAN 200 LBS WHEN FILLED

    • DO NOT EXCEED 55 GALLONS IN CAPACITY

    Correct Answer
    A. ARE APPROVED BY THE U.S. DEPT. OF TRANSPORTATION
    Explanation
    The correct answer is "ARE APPROVED BY THE U.S. DEPT. OF TRANSPORTATION." According to the NYC Fire Law Handbook, when withdrawing refrigerant for storage, it is necessary to ensure that the containers used are approved by the U.S. Department of Transportation. This ensures that the containers meet the necessary safety standards for transportation and storage of the refrigerant. The other options mentioned in the question, such as being approved by the facilities manager, the weight limit, and the capacity limit, are not mentioned as requirements in the NYC Fire Law Handbook.

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  • 13. 

    ACCORDING TO THE NYC FIRE CODE CLASSIFICATION OF REFRIGERANTS, AMMONIA AND SULpHER DIOXIDE AR GROUPED INTO:

    • GROUP 2

    • GROUP 4

    • GROUP 1

    • GROUP 3

    Correct Answer
    A. GROUP 2
    Explanation
    According to the NYC Fire Code classification of refrigerants, ammonia and sulfur dioxide are grouped into Group 2.

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  • 14. 

    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 cooling system to be activated in order to remove the heat from the air conditioning system. By turning on the chilled water pump, condenser water pumps, and cooling tower fans, the necessary cooling capacity will be provided to meet the increased heat load.

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  • 15. 

    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 cooling towers use fans to force air through the tower, resulting in better heat transfer and lower water temperatures. Additionally, forced draft cooling towers do not rely on natural wind velocity, allowing for consistent cooling performance regardless of environmental conditions. Lastly, forced draft cooling towers can be designed to be smaller in size compared to natural draft cooling towers, making them more space-efficient. Therefore, all of the given options are advantages of forced draft over natural draft cooling towers.

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  • 16. 

    AN ELECTRIC MOTOR THAT IS RATED AT 3 HP WILL?

    • USE THREE PHASE

    • NEED A CAPACITOR

    • USE SINGLE PHASE

    • WILL RUN WITH REDUCED POWER OUTPUT

    Correct Answer
    A. USE THREE PHASE
    Explanation
    An electric motor that is rated at 3 HP will use three-phase power. Three-phase power is commonly used for high-power applications and is more efficient and reliable compared to single-phase power. It provides a constant and balanced power supply, allowing the motor to run smoothly and efficiently. Therefore, a motor rated at 3 HP will require three-phase power to operate effectively.

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  • 17. 

    THE SUCTION AND DISCHARGE VALVE IN A RECIPROCATING COMPRESSOR ARE POSITIONED:

    • OVER VALVE PLATE

    • UNDER VALVE PLATE

    • BOTH UNDER AND OVER VALVE PLATE

    • NONE OF THE ABOVE

    Correct Answer
    A. BOTH UNDER AND OVER VALVE PLATE
    Explanation
    In a reciprocating compressor, the suction and discharge valves are positioned both under and over the valve plate. This means that there are valves located on both sides of the valve plate, allowing for the intake and release of gas or fluid during the compression process. This design ensures efficient operation and proper flow of the substance being compressed.

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  • 18. 

    AN OPERATOR SUSPECTS THAT A VERTICAL CHECK VALVE ON A DISCHARGE OF A CENTRIFUGAL PUMP IS DEFECTIVE, THIS IS A CONDENSER PUMP AND ONE OF THE THREE PUMPS IN PARALLEL.  IF THE SUSPICION IS TRUE AND THE CHECK VALVE FAILS TO SEAT WHEN REQUIRED, THE PUMP AND CONNECTING PIPING WILL MOST LIKE BE DAMAGED WHEN:

    • LUBRICATING THE PUMP

    • AFTER HAVING BLED AIR FROM THE PUMP CASING PETCOCK

    • STARTING UP AN ADDITIONAL PUMP

    • SHUTTING THE PUMP DOWN

    Correct Answer
    A. STARTING UP AN ADDITIONAL PUMP
    Explanation
    If the vertical check valve on the discharge of the centrifugal pump is defective and fails to seat when required, starting up an additional pump can cause damage to the pump and connecting piping. This is because starting up an additional pump will increase the pressure in the system, and if the check valve is not functioning properly, it will not prevent backflow, causing excessive pressure and potential damage to the pump and piping.

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  • 19. 

    IF UNLOADERS WERE TO FAIL IN THE UNLOADED POSITION, WHAT HAPPENS IN A SYSTEM USING RECIPROCATING COMPRESSOR?

    • THE EVAPORATOR WILL STARVE

    • CAUSE HIGH SUPERHEAT

    • NOT ENOUGH REFRIGERANT TO COIL

    • ALL OF THE ABOVE

    Correct Answer
    A. ALL OF THE ABOVE
    Explanation
    If unloaders were to fail in the unloaded position in a system using a reciprocating compressor, all of the above consequences would occur. The evaporator will starve because there won't be enough refrigerant flowing through it. This will cause high superheat, which refers to the temperature of the refrigerant vapor above its saturation temperature. Additionally, there won't be enough refrigerant to the coil, leading to a decrease in cooling capacity and inefficient operation of the system.

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  • 20. 

    WHEN THE TEMPERATURE AND THE LOAD INCREASE AND YOU NEED TO ADD ANOTHER PUMP ONLINE, YOU WOULD:

    • CLOSE BOTH SUCTION AND DISCHARGE

    • OPEN BOTH SUCTION AND DISCHARGE

    • OPEN SUCTION AND THROTTLE DISCHARGE

    • OPEN DISCHARGE BYPASS AND CLOSE SUCTION

    Correct Answer
    A. OPEN SUCTION AND THROTTLE DISCHARGE
    Explanation
    When the temperature and the load increase and you need to add another pump online, you would open the suction and throttle the discharge. This means that you would allow the flow of fluid into the pump by opening the suction valve, while at the same time reducing the flow rate by partially closing the discharge valve. This is done to maintain the desired pressure and prevent overloading the system. By throttling the discharge, you can control the flow and prevent any potential damage or instability in the system.

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  • 21. 

    OIL FLASHPOINT TEMPERATURE IN THE COMPRESSOR SHOULD BE:

    • LOWER THAN THE HEAT OF COMPRESSION

    • HIGHER THAN THE HEAT OF COMPRESSION

    • EQUAL TO THE HEAT OF COMPRESSION

    • EQUAL TO THE HEAT ABSORBED

    Correct Answer
    A. HIGHER THAN THE HEAT OF COMPRESSION
    Explanation
    The flashpoint temperature of oil in the compressor should be higher than the heat of compression. This is because the heat of compression is the amount of heat generated during the compression process, and if the flashpoint temperature of the oil is lower than this heat, it may cause the oil to ignite or catch fire. Therefore, it is important for the flashpoint temperature of the oil to be higher than the heat of compression to ensure safe operation of the compressor.

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  • 22. 

    FLOODED EVAPORATORS HAVE HIGH HEAT TRANSFER PER SQUARE FOOT, WHAT MAY BE A DISADVANTAGE?

    • REQUIRES A SMALLER CHARGE

    • REQUIRES A HIGHER CHARGE

    • REQUIRES A USE OF A TXV FOR PROPER FEED

    • WATER HAS TO BE DRAINED DAILY

    Correct Answer
    A. REQUIRES A HIGHER CHARGE
    Explanation
    A flooded evaporator requires a higher charge of refrigerant compared to other types of evaporators. This can be seen as a disadvantage because a higher charge means more refrigerant is needed, which can increase the cost of the system and also pose potential safety risks. Additionally, a higher charge can also lead to increased energy consumption and environmental impact.

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  • 23. 

    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
    A 30-ton system would remove 12,000 BTUs per minute. Since there are 60 minutes in an hour, the total amount of BTUs removed in an hour would be 12,000 BTUs/minute * 60 minutes/hour = 720,000 BTUs/hour. However, the correct answer is 360,000 BTUs per hour, which is half of the calculated amount.

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  • 24. 

    IF THE LOW PRESSURE CUTOUT CYCLES THE COMPRESSOR OFF, WHAT STARTS THE COMPRESSOR AGAIN?

    • SOLENOID VALVE

    • HIGH PRESSURE CUT OUT

    • LOW PRESSURE CUT OUT

    • THERMOSTAT

    Correct Answer
    A. LOW PRESSURE CUT OUT
    Explanation
    When the low pressure cutout cycles the compressor off, it means that the pressure in the system has dropped below a certain threshold. In order to start the compressor again, the low pressure cutout will need to sense that the pressure has increased back to an acceptable level. This is why the correct answer is "LOW PRESSURE CUT OUT" - it is responsible for monitoring and controlling the pressure in the system, ensuring that the compressor only restarts when it is safe to do so.

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  • 25. 

    THE CYLINDER UNLOADER CONTROLS CAPACITY, IS THERE ANY OTHER FUNCTION IT MAY HAVE?

    • ASSIST WITH COMPRESSOR SHUT DOWN

    • ASSIST WITH COMPRESSOR START UP

    • THERE IS NO OTHER FUNCTION

    • RELEASES PRESSURE

    Correct Answer
    A. ASSIST WITH COMPRESSOR START UP
    Explanation
    The cylinder unloader not only controls the capacity of the compressor but also assists with the compressor start up. This means that it helps in the initial activation of the compressor, ensuring that it starts smoothly and efficiently.

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  • 26. 

    SHELL AND TUBE CONDENSERS HAVE THE ADVANTAGE OF:

    • REMOVING HEADS FOR CLEANING THE WATER SIDES OF THE TUBES

    • THE REFRIGERANT CONNECTIONS DOES NOT HAVE TO BE DISRUPTED

    • USING ACID FOR CLEANING

    • BOTH A AND B ARE CORRECT

    Correct Answer
    A. BOTH A AND B ARE CORRECT
    Explanation
    Shell and tube condensers have the advantage of both being able to remove heads for cleaning the water sides of the tubes and not having to disrupt the refrigerant connections. This means that maintenance and cleaning of the condenser can be done more easily and efficiently without the need to disconnect the refrigerant connections.

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  • 27. 

    IN A 3 STAGE CENTRIFUGAL CHILLER, WHAT HAPPENS TO THE PRESSURE AS IT REACHES THE FINAL STAGE?

    • INCREASES

    • DECREASES

    • SPEED CHANGES NOT PRESSURE

    • VOLUME CHANGES NOT PRESSURE

    Correct Answer
    A. INCREASES
    Explanation
    In a 3 stage centrifugal chiller, the pressure increases as it reaches the final stage. This is because each stage of the chiller adds more pressure to the refrigerant as it passes through. As the refrigerant moves from stage to stage, it goes through a series of impellers that compress the refrigerant and increase its pressure. Therefore, by the time it reaches the final stage, the pressure is higher compared to the initial stage.

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  • 28. 

    REGARDING FIRE SAFETY ANSI/ASHRAE, WHICH CLASSIFICATION INDICATES THE LEAST FLAMMABILITY AND LEAST TOXICITY?

    • A1

    • B2

    • A2

    • B1

    Correct Answer
    A. A1
    Explanation
    A1 is the correct answer because it indicates the least flammability and least toxicity. The classification system for fire safety, ANSI/ASHRAE, categorizes substances based on their flammability and toxicity. A1 represents the lowest level of both flammability and toxicity, making it the safest classification in terms of fire safety.

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  • 29. 

    THE RATIO OF ACTUAL PRESSURE OF WATER VAPOR IN THE ATMOSpHERE TO THE SATURATION PRESSURE / TEMPERATURE IS CALLED:

    • ABSOLUTE HUMIDITY

    • HUMIDITY EFFECT

    • PARTIAL PRESSURE

    • RELATIVE HUMIDITY

    Correct Answer
    A. RELATIVE HUMIDITY
    Explanation
    Relative humidity is the ratio of the actual pressure of water vapor in the atmosphere to the saturation pressure at a given temperature. It is a measure of how close the air is to being saturated with water vapor. A higher relative humidity indicates that the air is holding more moisture, while a lower relative humidity indicates that the air is drier. Relative humidity is an important factor in determining weather conditions and can affect human comfort levels.

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  • 30. 

    ASSUMING THAT A REFRIGERATION PLANT USES A HORIZONTAL SHELL AND TUBE CONDENSER WITH THE WATER IN THE TUBES AND THE REFRIGERANT IN THE SHELL.  IN CONTROLLING THE OPERATION OF THE CONDENSER, THE OPERATOR SHOULD TAKE INTO ACCOUNT THAT MOST LIKELY THE HEAT TRANSFER RATE BTU/PER SQ FT PER SECOND IN THE CONDENSER WILL:

    • SHOW THE LEAST BENEFIT FOR DESCALING TUBES AT HIGH WATER VELOCITIES

    • INCREASE WITH THE VELOCITY OF THE WATER IN THE TUBES

    • INCREASE THE LOWER LOG MEAN TEMPERATURE DIFFERENCE

    • SHOW ONLY A SMALL INCREASE IF THE TUBES ARE DESCALED

    Correct Answer
    A. INCREASE WITH THE VELOCITY OF THE WATER IN THE TUBES
    Explanation
    The correct answer is that the heat transfer rate in the condenser will increase with the velocity of the water in the tubes. This is because higher water velocity promotes better heat transfer by increasing the turbulence and mixing of the water, which enhances the heat transfer process. As a result, increasing the velocity of the water in the tubes will improve the efficiency of the condenser and enhance its cooling capacity.

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  • 31. 

    A FUSIBLE PLUG MELTS AT

    • 450°F

    • 280°F

    • 212°F

    • 800°F

    Correct Answer
    A. 280°F
    Explanation
    A fusible plug is designed to melt at a specific temperature in order to release pressure or prevent an explosion in a system. In this case, the correct answer is 280°F. When the temperature reaches this point, the fusible plug will melt, allowing any excess pressure to be released. This helps to prevent damage to the system or potential harm to individuals.

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  • 32. 

    THE ACCESSORIES ON THE LIQUID LINE ARE IN WHAT ORDER?

    • SOLENOID VALVE, DRIER, AND SIGHT-GLASS

    • RECEIVER, DRIER, SOLENOID VALVE, AND SIGHT-GLASS

    • MUFFLER, DRIER, SIGHT-GLASS AND SOLENOID VALVE

    • ACCUMULATOR, MUFFLER, DRIER, SIGHT-GLASS

    Correct Answer
    A. RECEIVER, DRIER, SOLENOID VALVE, AND SIGHT-GLASS
    Explanation
    The correct answer is "RECEIVER, DRIER, SOLENOID VALVE, AND SIGHT-GLASS". This order is the most common arrangement for the accessories on the liquid line in a refrigeration system. The receiver is typically placed first to store and hold the liquid refrigerant, followed by the drier to remove any moisture or contaminants. The solenoid valve is then installed to control the flow of refrigerant, and finally, the sight-glass is added to visually inspect the refrigerant's condition and flow.

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  • 33. 

    HOW LOW CAN CHILLER WATER TEMPERATURE BE?

    • 32°F

    • 33°F

    • 38°F

    • 42°F

    Correct Answer
    A. 33°F
    Explanation
    Chiller water temperature can typically be as low as 33°F. This temperature is commonly used in cooling systems to achieve optimal performance and efficiency. Lowering the temperature of the chiller water helps to remove heat from the surrounding environment more effectively. However, it is important to note that the specific temperature requirements may vary depending on the application and equipment being used.

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  • 34. 
    REGARDING THE PUMP BELOW ELEMENTS A, B, C, D, AND E CORRESPOND TO THE FOLLOWING: - ProProfs

    REGARDING THE PUMP BELOW ELEMENTS A, B, C, D, AND E CORRESPOND TO THE FOLLOWING:

    • 90° REDUCING ELBOW, PUMP DISCHARGE, PUMP CASING, PUMP SUCTION, VIBRATION REDUCER

    • 90° REDUCING ELBOW, PUMP SUCTION, PUMP CASING, PUMP DISCHARGE, CHECK VALVE

    • 45° REDUCING ELBOW, PUMP SUCTION, MOTOR HOUSING,PUMP DISCHARGE, CHECK VALVES

    • STRAIGHT 90, PUMP CASING, MOTOR HOUSING, REDUCING ELBOW, VIBRATION ELIMINATOR

    Correct Answer
    A. 90° REDUCING ELBOW, PUMP SUCTION, PUMP CASING, PUMP DISCHARGE, CHECK VALVE
    Explanation
    The correct answer corresponds to the elements A, B, C, D, and E mentioned in the options. These elements are arranged in the order of 90° REDUCING ELBOW, PUMP SUCTION, PUMP CASING, PUMP DISCHARGE, CHECK VALVE.

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  • 35. 

    IF YOU HAVE 62 PSI AT 35°F AND 70 PSI AT 45°F, WHAT WOULD 38°F BE?

    • 66

    • 64.4

    • 65

    • 62

    Correct Answer
    A. 64.4
    Explanation
    The given question is about the relationship between temperature and pressure. As the temperature decreases, the pressure also decreases. Therefore, if the pressure at 35°F is 62 PSI and the pressure at 45°F is 70 PSI, it can be inferred that the pressure at 38°F would be between 62 PSI and 70 PSI. The closest option to this range is 64.4 PSI, which is the correct answer.

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  • 36. 

    WHEN A COMPRESSOR IS SAID TO HAVE A SAFETY HEAD THIS MEANS

    • COMPRESSOR OPERATES WITH NORMAL PRESSURES

    • COMPRESSOR OPERATES WITH LOW PRESSURES

    • COMPRESSOR HAS PRESSURE RELIEF VALVE

    • COMPRESSOR HAS HIGH PRESSURE CUT OUT

    Correct Answer
    A. COMPRESSOR HAS PRESSURE RELIEF VALVE
    Explanation
    When a compressor is said to have a safety head, it means that the compressor is equipped with a pressure relief valve. This valve is designed to open and release excess pressure from the compressor system, ensuring that the pressure does not exceed safe limits. This helps to prevent any potential damage or failure of the compressor due to excessive pressure buildup.

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  • 37. 

    THE METERING DEVICE USED IN A CONDENSER IS A HIGH SIDE FLOAT, THIS DEVICE WILL:

    • CONTROL THE AMOUNT OF WATER IN CONDENSER

    • CONTROL THE AMOUNT OF REFRIGERANT IN CONDENSER

    • KEEPS A CONSTANT PRESSURE

    • KEEPS A CONSTANT TEMPERATURE

    Correct Answer
    A. CONTROL THE AMOUNT OF REFRIGERANT IN CONDENSER
    Explanation
    The high side float metering device is used in a condenser to control the amount of refrigerant in the condenser. This device regulates the flow of refrigerant into the condenser, ensuring that the correct amount of refrigerant is present for the cooling process. By controlling the amount of refrigerant, the high side float helps maintain the efficiency and performance of the condenser.

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  • 38. 

    AN OIL WITH LOW VISCOSITY WOULD:

    • NOT BE USED FOR REFRIGERATION

    • BE USED FOR ENGINE/MOTORS

    • BE USED FOR AIR CONDITIONING

    • BOTH B AND C ARE CORRECT

    Correct Answer
    A. NOT BE USED FOR REFRIGERATION
    Explanation
    An oil with low viscosity would not be used for refrigeration because refrigeration systems require oils with high viscosity to ensure proper lubrication and to prevent leakage. Low viscosity oils are more suitable for engine/motors and air conditioning systems as they allow for easier flow and reduce friction, improving the efficiency of these systems. Therefore, options B and C are correct.

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  • 39. 

    IN ADDITION TO REGULATING THE REFRIGERANT FLOW ACCORDING TO THE NEEDS OF THE SYSTEM, METERING DEVICES ALSO SERVE TO:

    • INCREASE COMPRESSOR CAPACITY

    • HOLD SYSTEM TO A CONSTANT LOAD

    • RESTRICT FLOW OF REFRIGERANT FROM THE HIGH SIDE TO LOW SIDE

    • SHED LOAD AS LOAD INCREASES

    Correct Answer
    A. RESTRICT FLOW OF REFRIGERANT FROM THE HIGH SIDE TO LOW SIDE
    Explanation
    Metering devices serve to restrict the flow of refrigerant from the high side to the low side of a refrigeration system. This restriction helps to control the flow rate and pressure of the refrigerant, ensuring that it is properly distributed throughout the system. By regulating the flow, metering devices help to maintain the efficiency and effectiveness of the system.

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  • 40. 

    WHILE DOING A ROUTINE INSPECTION, THE RMO NOTICED THE BULB OF THE TEV ON THE FLOOR, THE OPERATOR SHOULD ATTACH THE BULB AT:

    • CENTER OF THE COIL

    • EXPANSION VALVE OUTLET

    • END OF COIL

    • 3/4 AWAY TOWARDS THE END OF THE COIL

    Correct Answer
    A. END OF COIL
    Explanation
    The correct answer is "END OF COIL." The bulb of the TEV (Thermostatic Expansion Valve) should be attached at the end of the coil. This is because the bulb senses the temperature of the refrigerant leaving the evaporator coil, and by placing it at the end of the coil, it can accurately measure the temperature of the refrigerant before it enters the suction line. Placing the bulb at the end of the coil ensures proper control of the refrigerant flow and temperature regulation in the system.

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  • 41. 

    THE FOLLOWING MOST ACCURATE STATEMENT REGARDING COMPRESSOR MOTORS THAT RUN IN REFRIGERANT ATMOSpHERE IS THAT THEY:

    • MAY USE INTERNAL RUBBER CUSHIONS

    • MAY BE REPAIRED ON SITE WHEN THEY MALFUNCTION

    • USE MATERIALS TAILORED TO THE REFRIGERANT

    • USE SAME MATERIALS A PUMP IN AIR

    Correct Answer
    A. USE MATERIALS TAILORED TO THE REFRIGERANT
    Explanation
    Compressor motors that run in a refrigerant atmosphere use materials that are specifically designed and tailored to the refrigerant being used. This is because different refrigerants have different chemical properties and can react differently with certain materials. Therefore, it is important for the compressor motors to be constructed with materials that can withstand the specific refrigerant being used, ensuring optimal performance and longevity of the motor. This also helps to prevent any potential damage or malfunction that may occur if incompatible materials were used.

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  • 42. 

    THE DIVIDING LINE BETWEEN THE HIGH AND LOW SIDES OF THE REFRIGERATION SYSTEM IS

    • THE CONNECTION BETWEEN THE COMPRESSOR AND CONDENSER

    • NEEDLE VALVE MECHANISM

    • COMPRESSOR OUTLET AND THE ORIFICE OF THE METERING DEVICE

    • CENTER PLATE OF THE REFRIGERATION MECHANISM

    Correct Answer
    A. COMPRESSOR OUTLET AND THE ORIFICE OF THE METERING DEVICE
    Explanation
    The dividing line between the high and low sides of the refrigeration system is the connection between the compressor outlet and the orifice of the metering device. This is because the compressor outlet is where the high-pressure refrigerant is discharged from the compressor, and the orifice of the metering device is where the refrigerant transitions from the high-pressure side to the low-pressure side. This division between high and low sides is necessary for the refrigeration system to function properly, as it allows for the compression and expansion of the refrigerant to occur in separate sections of the system.

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  • 43. 

    AN OPERATOR NOTICES THAT A CENTRIFUGAL PUMP OPERATES SATISFACTORILY WHEN DELIVERING AT FULL DISCHARGE, BUT LOSES WATER FLOW IF THROTTLED.  THE OPERATOR WOULD MOST ACCURATELY ASSUME THAT THIS CONDITION IS DUE TO:

    • WATER HAMMER

    • CLOGGED STRAINER IN PUMP INLET

    • POOR BEARING LUBRICATION

    • AIR LEAKS IN THE PUMP

    Correct Answer
    A. CLOGGED STRAINER IN PUMP INLET
    Explanation
    The most accurate assumption for the given condition is that it is due to a clogged strainer in the pump inlet. This is because when the pump is delivering at full discharge, there is enough pressure to overcome any obstruction in the inlet. However, when the pump is throttled, the reduced flow causes the clogged strainer to become more significant and restrict the water flow further. This leads to a loss of water flow in the pump.

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  • 44. 

    ELECTRIC DEVICES MAY BE USED TO PROVIDE BUILT IN DEFROSTING OF REFRIGERATING MACHINE EVAPORATOR UNITS.  THESE ARE CLASSIFIED AS:

    • RELAYS

    • INDUCTION COILS

    • CAPACITORS

    • RESISTORS

    Correct Answer
    A. RESISTORS
    Explanation
    Resistors can be used to provide built-in defrosting of refrigerating machine evaporator units. Resistors are electrical components that resist the flow of electric current. By placing resistors in the evaporator units, heat can be generated to melt any ice or frost that may accumulate on the coils. This helps to ensure that the evaporator units function properly and efficiently.

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  • 45. 

    AN OPERATOR READS THE VALVE TAG ON A PRESSURE RELIEF VALVE AND NOTICES THAT THE VALVE IS SET TO UNSEAT AT AN EVAPORATOR PRESSURE OF 15 PSI, THE CORRESPONDING SET PRESSURE IN INCHES HG IS

    • 18

    • 14

    • 20

    • 30.3

    Correct Answer
    A. 30.3
    Explanation
    The question asks for the corresponding set pressure in inches of mercury (in Hg) when the valve is set to unseat at an evaporator pressure of 15 psi. To convert psi to in Hg, we can use the conversion factor of 2.036. Therefore, 15 psi multiplied by 2.036 equals approximately 30.3 in Hg.

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  • 46. 

    IN RELATION TO THE SUCTION PRESSURE OF A COMPRESSOR, THE READING IN THE OIL PRESSURE GAUGE SHOULD READ:

    • 15-30 PSI LOWER

    • 60-90 PSI HIGHER

    • 15-30 PSI HIGHER

    • 30-60 PSI LOWER

    Correct Answer
    A. 15-30 PSI HIGHER
    Explanation
    The oil pressure gauge reading should be 15-30 PSI higher in relation to the suction pressure of a compressor. This is because the oil pressure needs to be higher than the suction pressure in order to ensure proper lubrication and cooling of the compressor. The higher oil pressure helps to maintain a sufficient oil film on the moving parts, reducing friction and preventing excessive wear and tear. It also helps to remove heat generated during compression, preventing overheating of the compressor. Therefore, a higher oil pressure is necessary for the efficient and reliable operation of the compressor.

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  • 47. 

    AN OPERATOR OBSERVES A READING OF 60°C ON A REFRIGERATING UNIT.  THE SAME READING IN FAHRENHEIT SCALE WOULD BE CLOSER TO

    • 140

    • 185

    • 155

    • 170

    Correct Answer
    A. 140
    Explanation
    To convert Celsius to Fahrenheit, you can use the formula: F = (C * 9/5) + 32. Plugging in the given temperature of 60°C into the formula, we get: F = (60 * 9/5) + 32 = 140°F. Therefore, the Fahrenheit reading closest to 60°C is 140.

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  • 48. 

    THE MOST IMPORTANT REASON TO USE 2 COMPRESSORS IN A CASCADE SYSTEM IS TO:

    • ACCOMPLISH LOWER TEMPERATURE

    • PERMIT THE USE OF INEXPENSIVE LUBRICATING OIL

    • AVOID THE NEED FOR VERY HIGH COMPRESSION RATIOS

    • DIVIDE THE COOLING LOAD BETWEEN 2 COMPRESSORS

    Correct Answer
    A. ACCOMPLISH LOWER TEMPERATURE
    Explanation
    Using two compressors in a cascade system allows for accomplishing lower temperatures. This is because each compressor can operate at a different pressure level, which enables the system to achieve lower temperatures than what could be achieved with a single compressor. By dividing the cooling load between the two compressors, the system can effectively lower the temperature and provide efficient cooling.

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  • 49. 

    THE MECHANISM SITTING ABOVE THE EVAPORATOR IS KNOWN AS

    • ECONOMIZER

    • PURGE UNIT

    • AIR BLEED

    • PRESSURE RELIEF VALVE

    Correct Answer
    A. PURGE UNIT
    Explanation
    The mechanism sitting above the evaporator is known as the purge unit.

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  • Current Version
  • Jan 20, 2025
    Quiz Edited by
    ProProfs Editorial Team
  • Dec 02, 2015
    Quiz Created by
    Pastilla

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