Refrigerant Machine Operator Test # 4

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  • 1/66 Questions

    The sole refrigeration engineer on duty in a building is permitted to leave the building refrigeration system is in operation only when

    • Lunch or dinner occur
    • System is in automatic operation 
    • Relieved by another licensed refrigeration engineer 
    • The assistant provides coverage or supervision
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About This Quiz

Refrigerant Machine Operator Test #4 evaluates knowledge on HVAC systems, focusing on cooling towers, temperature conversions, steam eductors, and refrigerant flow. It's designed for operators to understand system dynamics and operational adjustments under varying conditions.

Refrigerant Machine Operator Test # 4 - Quiz

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  • 2. 

    When changing water to ice, what must be removed?

    • Specific heat 

    • Latent heat 

    • Sensible heat 

    • N/A

    Correct Answer
    A. Latent heat 
    Explanation
    When changing water to ice, latent heat must be removed. Latent heat is the energy required to change the state of a substance without changing its temperature. In the case of water, when it reaches its freezing point and changes from a liquid to a solid (ice), latent heat must be removed from the water in order for this phase change to occur.

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  • 3. 

    Vice-President of operations comes in on a cold winter day and ask the RMO to go shovel snow.  What should he do?

    • Obey the manger and go out and shovel snow with radio communication 

    • As long as you check in every 45 minutes

    • Do not go out and shovel snow until another licensed engineer relieves you 

    • Call the union shop and fill out a report, but shovel snow 

    Correct Answer
    A. Do not go out and shovel snow until another licensed engineer relieves you 
    Explanation
    The correct answer advises against going out to shovel snow until another licensed engineer relieves you. This is because shoveling snow can be a hazardous task, especially in cold winter conditions. It is important to ensure that there is always a licensed engineer present to handle any potential emergencies or issues that may arise during the snow shoveling process. Waiting for another licensed engineer to relieve you helps to maintain safety and ensure that operations can continue smoothly.

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  • 4. 

    If R134 contact your skin, what would you do?

    • Nothing, it is HFC

    • Use body oil on skin 

    • Flush with water until removed

    • Make sure you have proper air movement over skin to evaporate 

    Correct Answer
    A. Flush with water until removed
    Explanation
    If R134 contacts your skin, the best course of action would be to flush it with water until it is completely removed. R134 is a type of HFC (hydrofluorocarbon), which is commonly used in refrigeration and air conditioning systems. While HFCs are generally considered to be safe, it is still important to take precautions if it comes into contact with your skin. Flushing with water helps to dilute and remove the substance, reducing the risk of any potential irritation or adverse effects.

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  • 5. 

    The orifice plate meters the refrigerant.  What else can be said about the vessel that contains the orifice plate?

    • It is a vapor recycler 

    • It cleans the refrigerant 

    • It economizes

    • It acts as a condenser for subcooling 

    Correct Answer
    A. It economizes
    Explanation
    The vessel that contains the orifice plate economizes. This means that it helps to save or reduce the usage of resources, in this case, the refrigerant. It likely achieves this by controlling the flow of refrigerant through the orifice plate, ensuring that only the necessary amount is used for the system to function efficiently.

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  • 6. 

    If the city water is too expensive, you can use water from:

    • Well

    • Lake

    • All answers are correct

    • River 

    Correct Answer
    A. All answers are correct
    Explanation
    All the options listed (well, lake, river) can be used as alternative sources of water if the city water is too expensive. This means that any of these sources can be accessed and utilized as a substitute for city water, depending on availability and feasibility.

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  • 7. 

    Which of the following statements should be imprinted on the body of a fusible plug?

    • Temperature at which the fusible member melts 

    • Date manufactured

    • Busting pressure 

    • Maximum operating pressure 

    Correct Answer
    A. Temperature at which the fusible member melts 
    Explanation
    The correct answer is "temperature at which the fusible member melts". This statement should be imprinted on the body of a fusible plug because it is crucial information for the proper functioning of the plug. The fusible member is designed to melt at a specific temperature, allowing for the release of pressure in the event of overheating or excessive pressure. Knowing this temperature is essential for maintaining the safety and effectiveness of the fusible plug.

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  • 8. 

    What is the most common metering device on a reciprocating system?

    • Thermostatic expansion valve 

    • Automatic expansion valve 

    • Orifice 

    • Capillary tube 

    Correct Answer
    A. Thermostatic expansion valve 
    Explanation
    The most common metering device on a reciprocating system is the thermostatic expansion valve. This valve regulates the flow of refrigerant into the evaporator coil based on the temperature and pressure conditions. It ensures that the right amount of refrigerant is supplied to the evaporator, allowing for efficient cooling and preventing any potential damage to the system. The other options mentioned, such as the automatic expansion valve, orifice, and capillary tube, are also used as metering devices in some systems, but the thermostatic expansion valve is the most commonly used.

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  • 9. 
    What is this used for:  - ProProfs

    What is this used for: 

    • CO2

    • O2

    • Halogen

    • Leak detection 

    Correct Answer
    A. Leak detection 
    Explanation
    This list of substances (CO2, O2, Halogen) suggests that the purpose of this item is leak detection. These substances are commonly used in leak detection systems to detect leaks in various systems or equipment. By monitoring the presence or absence of these substances, it is possible to identify and locate leaks accurately.

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  • 10. 

    The use of oil in the refrigeration machine is to 

    • Mix the oil with liquid refrigerant 

    • Add non condensables to refrigerant 

    • Reduce friction in the compressor parts 

    • None of the above 

    Correct Answer
    A. Reduce friction in the compressor parts 
    Explanation
    The use of oil in the refrigeration machine is to reduce friction in the compressor parts. Oil is added to the compressor to lubricate the moving parts and reduce friction, which helps in the smooth operation of the compressor and extends its lifespan. Without oil, the compressor parts would experience increased friction, leading to wear and tear, decreased efficiency, and potential breakdown of the machine.

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  • 11. 

    After completing repair to a refrigeration system, you leak check the system with your electronic leak detector.  After no leaks are found, proper disposal of the R-22 and nitrogen mix to :

    • Separate refrigerant from nitrogen and vent 

    • Recover the mixture and mark to be destroyed 

    • Vent the mixture to the outside air 

    • You cannot use R-22 for this purpose 

    Correct Answer
    A. Vent the mixture to the outside air 
    Explanation
    After completing the repair to the refrigeration system and confirming that there are no leaks, the proper disposal method for the R-22 and nitrogen mix is to vent the mixture to the outside air. This means releasing the mixture into the atmosphere. This is the correct answer because venting the mixture is a common practice for disposing of refrigerants, especially when there are no leaks present. However, it is important to note that venting refrigerants is not environmentally friendly and should be avoided whenever possible.

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  • 12. 

    Oil that has been separated from the refrigerant is returned to the compressor and tied into the  

    • Oil charging valve 

    • Discharge service valve 

    • Oil pump suction 

    • Compressor crankcase

    Correct Answer
    A. Compressor crankcase
    Explanation
    The oil that has been separated from the refrigerant is returned to the compressor crankcase. This is where the oil is stored and circulated within the compressor. By returning the oil to the crankcase, it ensures that the compressor has a sufficient supply of oil for lubrication and cooling. This helps to maintain the efficiency and longevity of the compressor.

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  • 13. 

    When conducting a routine tour of the plant, an RMO notices a significant increase in superheat for a reciprocating compressor. Of the following, the most likely cause of this would be?

    • Scale particles lodged in the TEV

    • Unraveling of the insulation covering the thermal bulb of the TEV

    • Overcharge of refrigerant 

    • Noncondensables in the system 

    Correct Answer
    A. Scale particles lodged in the TEV
    Explanation
    The most likely cause of the significant increase in superheat for a reciprocating compressor is scale particles lodged in the TEV. Scale particles can obstruct the flow of refrigerant through the thermal expansion valve (TEV), causing it to malfunction and leading to an increase in superheat. This can result in inefficient cooling and potential damage to the compressor. The other options - unraveling of the insulation covering the thermal bulb of the TEV, overcharge of refrigerant, and noncondensables in the system - may also cause issues in the system, but they are not as likely to directly cause an increase in superheat as scale particles lodged in the TEV.

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  • 14. 

    An RMO is inspecting a centrifugal pump and he notices excessive water leaking from the mechanical seal.  The RMO should:

    • Tighten evenly to get a steady drip 

    • This is normal for a mechanical seal

    • Shut down the pump, turn on the standby and call for pump service 

    • Order a new pump because mechanical seals cannot be replaced

    Correct Answer
    A. Shut down the pump, turn on the standby and call for pump service 
    Explanation
    The correct answer is to shut down the pump, turn on the standby, and call for pump service. Excessive water leaking from the mechanical seal indicates a problem with the seal, which can lead to further damage if not addressed. Shutting down the pump and turning on the standby ensures that the pump is not running while the issue is being resolved. Calling for pump service is necessary to have a professional inspect and repair the mechanical seal.

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  • 15. 

    A systems condenser  water pump has been shut down for service.  When it is turned back on, it is discovered that it is not moving water.  What should the RMO do?

    • Check the shaft bearings for grease

    • Check the contacts with the voltmeter for correct voltage 

    • Open the petcock and bleed air from volute 

    • Bleed excess water pressure from the bottom plug 

    Correct Answer
    A. Open the petcock and bleed air from volute 
    Explanation
    The RMO should open the petcock and bleed air from the volute. When the condenser water pump is shut down for service, air can enter the system and become trapped in the volute, preventing the pump from moving water. Bleeding the air from the volute will allow water to flow properly through the pump. Checking the shaft bearings for grease, checking the contacts with a voltmeter for correct voltage, and bleeding excess water pressure from the bottom plug are not relevant actions in this scenario.

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  • 16. 

    As and RMO in charge of a refrigeration machine in your building controlling the capacity of the machine, how does the solenoid valve unloader get activated?

    • With spring pressure 

    • With pneumatic pressure

    • With electric current in a coil causing the plunger to lift 

    • None of the above 

    Correct Answer
    A. With electric current in a coil causing the plunger to lift 
    Explanation
    The solenoid valve unloader gets activated with electric current in a coil causing the plunger to lift. This is because a solenoid valve is an electromechanical device that uses an electric current to create a magnetic field, which in turn moves the plunger and controls the flow of fluid or gas. When the electric current is applied to the coil, the magnetic field is generated, causing the plunger to lift and activate the solenoid valve unloader.

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  • 17. 

    What is the minimum required times that the RMO needs to perform rounds on equipment and fill out the log book, per NYC Fire Dept.

    • Once per shift

    • Once a day 

    • Every two hours 

    • Every hour 

    Correct Answer
    A. Once per shift
    Explanation
    The minimum required times that the RMO needs to perform rounds on equipment and fill out the log book, as per the NYC Fire Dept, is once per shift. This means that the RMO is expected to perform the rounds and fill out the log book only once during their entire shift.

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  • 18. 

    When considering the rate of BTUs rejected by the condenser, an important point for the operator to remember is:

    • Will increase if you oversize the tower 

    • Will decrease as the water temperature goes down

    • Will increase as the velocity goes up

    • Will show no difference as long as the water temperature is the same

    Correct Answer
    A. Will increase as the velocity goes up
    Explanation
    The correct answer is "will increase as the velocity goes up." This means that the rate of BTUs rejected by the condenser will increase when the velocity of the water flowing through the condenser increases. This is because higher velocity leads to better heat transfer between the water and the condenser, resulting in more BTUs being rejected.

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  • 19. 
    The valve that is shown is used to: - ProProfs

    The valve that is shown is used to:

    • Add oil 

    • Remove oil

    • Charge refrigerant 

    • Add and remove oil

    Correct Answer
    A. Add and remove oil
    Explanation
    The valve shown is designed to both add and remove oil. It is commonly used in refrigeration systems where oil is required for lubrication. The valve allows for easy access to add oil when needed and also provides a means to remove excess or contaminated oil from the system. This helps to maintain the proper oil levels and quality, ensuring the efficient and smooth operation of the system.

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  • 20. 

    A valve that will not provide continuos flow of refrigerant through the circuit is the:

    • Globe valve

    • Service valve

    • Solenoid valve

    • TXV

    Correct Answer
    A. Solenoid valve
    Explanation
    A solenoid valve is a type of valve that is controlled by an electric current. It is commonly used in refrigeration systems to control the flow of refrigerant. Unlike other valves such as globe valves and service valves, a solenoid valve can be opened or closed rapidly, allowing for precise control of the refrigerant flow. However, it is not designed to provide continuous flow of refrigerant through the circuit. It is typically used to regulate the flow or completely shut off the refrigerant when needed. Therefore, a solenoid valve is the correct answer.

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  • 21. 

    What is the state of the refrigerant as it enters and exits the compressor?

    • Low temperature liquid in and high temperature liquid out 

    • Low temperature vapor in and high temperature vapor out 

    • Low temperature in and high temperature out 

    • Low pressure in and high pressure out 

    Correct Answer
    A. Low temperature vapor in and high temperature vapor out 
    Explanation
    As the refrigerant enters the compressor, it is in a low temperature vapor state. This means that it is in a gaseous form but at a low temperature. As the refrigerant exits the compressor, it is still in a vapor state but now at a high temperature. This indicates that the refrigerant has been compressed and its temperature has increased.

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  • 22. 

    After condensate water leaves the recirculation valve, where does it go?

    • Back to the boiler 

    • Down the drain back 

    • Back to the hot well for priming 

    • Back to turbine 

    Correct Answer
    A. Back to the hot well for priming 
    Explanation
    After condensate water leaves the recirculation valve, it goes back to the hot well for priming. The hot well is a reservoir that collects and stores condensate water from various parts of the system. Priming refers to the process of returning the condensate water back to the boiler for reuse. This ensures that the water is properly treated and heated before being circulated back into the system.

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  • 23. 

    It has been determined that the oil level in a particular refrigeration system is low, additional oil should be charged into the system by 

    • Pumping it through the suction service valve 

    • Pumping it into the compressor crankcase 

    • Pumping it into the king valve 

    • Using the gauge manifold to draw through both service valves simultaneously

    Correct Answer
    A. Pumping it into the compressor crankcase 
    Explanation
    When the oil level in a refrigeration system is low, additional oil should be charged into the system by pumping it into the compressor crankcase. The compressor crankcase is the part of the system where the compressor is located, and it is designed to hold and distribute the oil throughout the system. By pumping the oil directly into the compressor crankcase, it ensures that the oil will be properly distributed to lubricate the compressor and other components of the system, preventing damage and ensuring efficient operation.

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  • 24. 

    Solenoid valves are characterized by an electromagnet.  Which of the following will take place when a normally close solenoid is energized?

    • Valve disc will rotate 180 degrees 

    • Valve will meter flow of refrigerant to evaporator 

    • Valve plunger will lift off the seat 

    • Magnetic force will close contact 

    Correct Answer
    A. Valve plunger will lift off the seat 
    Explanation
    When a normally closed solenoid is energized, the valve plunger will lift off the seat. This is because the electromagnetic force generated by the solenoid causes the plunger to move upwards, creating an opening between the plunger and the seat. This allows the flow of fluid or gas through the valve, enabling the passage of refrigerant to the evaporator or any other intended application.

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  • 25. 

    Which one of the following will connect to the middle port on a gauge manifold?

    • Solenoid valve 

    • King valve 

    • Vacuum pump 

    • Suction or discharge service valves 

    Correct Answer
    A. Vacuum pump 
    Explanation
    A gauge manifold is used to measure and control pressure in a system. The middle port on a gauge manifold is typically connected to a vacuum pump. A vacuum pump is used to remove air and other gases from a system, creating a vacuum. By connecting the vacuum pump to the middle port on the gauge manifold, the pressure in the system can be accurately measured and controlled. Solenoid valves, king valves, and suction or discharge service valves are not typically connected to the middle port on a gauge manifold.

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  • 26. 

    On a water cooled chiller, the heat that is absorbed by the chilled water is:

    • Rejected to the ambient air as sensible heat 

    • Rejected as latent and sensible heat heat to the ambient air

    • Minimal in comparison to the volume of water 

    • Rejected by the compressor

    Correct Answer
    A. Rejected as latent and sensible heat heat to the ambient air
    Explanation
    The heat absorbed by the chilled water in a water cooled chiller is rejected to the ambient air as both latent and sensible heat. This means that the heat is transferred to the surrounding air in two forms - sensible heat, which can be felt and measured by a thermometer, and latent heat, which is released when water vapor condenses. This dual rejection of heat helps to cool down the chilled water and maintain the desired temperature in the chiller system.

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  • 27. 

    The recirculation valve on a surface condenser is controlled by the: 

    • Hot well level control 

    • The condensate pumps 

    •  pneumatic controller 

    • Oil pump pressure 

    Correct Answer
    A. Hot well level control 
    Explanation
    The recirculation valve on a surface condenser is controlled by the hot well level control. The hot well level control is responsible for maintaining the desired level of water in the hot well, which is the collection point for condensed steam. By controlling the hot well level, the recirculation valve can be adjusted to regulate the flow of condensed steam back into the condenser, ensuring efficient operation and preventing overflow or underflow in the hot well.

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  • 28. 

    Why is it important to minimize moisture in the inlet steam to a turbine?

    • Prevent damage to turbine blades

    • It takes longer to warm up with moisture 

    • Acids can form in the surface condenser

    • Moisture has no effect, steam is heated moisture 

    Correct Answer
    A. Prevent damage to turbine blades
    Explanation
    It is important to minimize moisture in the inlet steam to a turbine in order to prevent damage to turbine blades. Moisture in the steam can cause erosion and corrosion of the blades, leading to decreased efficiency and potential failure of the turbine. By minimizing moisture, the risk of damage to the turbine blades is reduced, ensuring the smooth operation and longevity of the turbine.

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  • 29. 

    You are the RMO of a facility which contains a 750 ton centrifugal Trane chiller.  The chief ask you to order extra refrigerant for the upcoming season.  If the machine charge is determined to be 1500lbs, how much refrigerant can you store without being in violation of the code?

    • Whatever the chief engineer deems safe 

    • Whatever can be tied down and stored safely 

    • 200lbs of refrigerant 

    • 330 lbs of refrigerant 

    Correct Answer
    A. 330 lbs of refrigerant 
    Explanation
    The correct answer is 330 lbs of refrigerant. This is because the question asks for the maximum amount of refrigerant that can be stored without violating the code. Since the machine charge is determined to be 1500 lbs, it is safe to store up to 330 lbs of refrigerant without violating the code.

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  • 30. 

    An automatic oil trap is installed in the high side of a refrigeration system.  When the float of the traps lifts it allows:

    • Hot oil to defrost the coils 

    • Hot oil to go through the stuffing box 

    • Oil to drain off into the receiver reservoir 

    • Oil to leave the trap and return to the compressor

    Correct Answer
    A. Oil to leave the trap and return to the compressor
    Explanation
    The automatic oil trap is designed to separate the oil from the refrigerant in the high side of the refrigeration system. When the float of the trap lifts, it allows the oil to leave the trap and return to the compressor. This ensures that the oil is properly circulated and lubricates the compressor, preventing any potential damage or wear. By returning the oil to the compressor, the system can operate efficiently and effectively.

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  • 31. 

    What is the diaphragm of the power assembly of a TEV made of? 

    • Copper 

    • Flexible rubber 

    • Flexible steel

    • N/A

    Correct Answer
    A. Flexible steel
    Explanation
    The diaphragm of the power assembly of a TEV is made of flexible steel. This material is chosen because it allows for movement and flexibility while maintaining strength and durability. The flexible steel diaphragm is able to withstand the pressure and temperature changes that occur in the power assembly of a TEV, ensuring proper functioning and efficient control of the refrigerant flow.

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  • 32. 

    There are two refrigerating systems. System "A" operates with a suction pressure of 18 PSIG and a speed of 230 RPM.  It is absorbing 800 BTUs per minute in its evaporator.  The second system "B" is operating with a suction pressure of 22 PSIG and a speed of 300 RPM.  It is absorbing 600 BTUs per minute from a brine tank.  From the data given it can be said that:

    • "A" is producing three tons and "B" is producing for tons

    • "A" is producing four tons and "B" is producing four tons 

    • "A" is producing four tons and "B" is producing three tons 

    • "A" is producing three tons and "B" is producing three tons 

    Correct Answer
    A. "A" is producing four tons and "B" is producing three tons 
    Explanation
    Based on the given information, the cooling capacity of a refrigerating system is directly proportional to the amount of heat absorbed per unit of time. System "A" is absorbing 800 BTUs per minute, while system "B" is absorbing 600 BTUs per minute. Therefore, system "A" has a higher cooling capacity than system "B". Since one ton of refrigeration is equivalent to 12,000 BTUs per hour, it can be concluded that system "A" is producing four tons (48,000 BTUs per hour) and system "B" is producing three tons (36,000 BTUs per hour).

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  • 33. 

    What is the most used regulation book in the U.S. used by the RMO?

    • NFPA

    • USEPA

    • Federal Regulation book 

    • NYC building code 

    Correct Answer
    A. USEPA
    Explanation
    The correct answer is USEPA. USEPA stands for the United States Environmental Protection Agency. It is the most used regulation book in the U.S. used by the RMO (Responsible Managing Officer) as it covers a wide range of environmental regulations and guidelines that need to be followed in order to protect the environment and public health. The USEPA regulations cover various areas such as air quality, water quality, hazardous waste management, and pollution prevention. Compliance with USEPA regulations is crucial for businesses and industries to ensure they are operating in an environmentally responsible manner.

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  • 34. 

    You notice that the second stage compressor on your reciprocating chiller has foaming in the oil sight glass.  As an operator you should check for:

    • Excessive charge 

    • Burnt out crankcase heater

    • Moisture in the system 

    • Too much oil 

    Correct Answer
    A. Burnt out crankcase heater
    Explanation
    Foaming in the oil sight glass of the second stage compressor indicates a potential issue with the crankcase heater. The crankcase heater is responsible for preventing the oil from becoming too cold and thick, which can lead to foaming. If the crankcase heater is burnt out or not functioning properly, it can result in foaming. Therefore, as an operator, it is important to check for a burnt out crankcase heater when encountering foaming in the oil sight glass.

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  • 35. 

    The medium/mediums for cooling in an evaporative condenser is/are:

    • Air only 

    • Refrigerant and water 

    • Water and air 

    • Glycol and air 

    Correct Answer
    A. Water and air 
    Explanation
    The correct answer is water and air. Evaporative condensers use water and air as the mediums for cooling. The process involves the evaporation of water which absorbs heat from the refrigerant, thereby cooling it. The water is circulated over a heat exchanger while air is blown through the exchanger, facilitating the evaporation process and dissipating the heat. This combination of water and air is essential for efficient cooling in evaporative condensers.

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  • 36. 

    If the temperature outside drops b 8 deg.C, what is the equivalent drop in def.F?

    • 4 deg.F

    • 40 deg.F

    • 14 deg.F

    • 8 deg.F

    Correct Answer
    A. 14 deg.F
    Explanation
    If the temperature outside drops by 8 deg.C, the equivalent drop in def.F can be calculated using the formula: def.F = (9/5 * deg.C) + 32. Plugging in the value of -8 deg.C, we get def.F = (9/5 * -8) + 32 = 14 deg.F. Therefore, the correct answer is 14 deg.F.

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  • 37. 

    An RMO notices that the diameter of the suction line is 36" and the diameter of the discharge line is 18".  What can we determine from this statement?

    • The unit is piped wrong because the diameters should be opposite

    • The cold refrigerant vapor needs less space than a hot vapor 

    • The high pressure line needs more diameter to handle the pressure

    • The higher the vapor pressure is, the less volume is needed

    Correct Answer
    A. The higher the vapor pressure is, the less volume is needed
    Explanation
    The correct answer suggests that the higher the vapor pressure, the less volume is needed. This means that the diameter of the suction line being larger than the discharge line is intentional and correct. It indicates that the system is designed to handle high vapor pressure, which requires less volume.

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  • 38. 

    When looking at a large semi-hermetic reciprocating compressor,  you would expect to find:

    • Suction and discharge lines parallel to each other

    • Suction and discharge lines perpendicular to each other 

    • Depends on the amount of cylinders

    • Suction on top and discharge off the bottom 

    Correct Answer
    A. Suction and discharge lines perpendicular to each other 
    Explanation
    In a large semi-hermetic reciprocating compressor, the suction and discharge lines are expected to be perpendicular to each other. This configuration allows for efficient flow of the refrigerant through the compressor. The perpendicular arrangement helps to minimize pressure drop and maximize the compressor's performance.

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  • 39. 

    An automatic purge unit is required on units:

    • With centrifugal compressors

    • Containing low pressure refrigerants

    • Absorption systems 

    • Double indirect open spray systems 

    Correct Answer
    A. Containing low pressure refrigerants
    Explanation
    An automatic purge unit is required on units containing low pressure refrigerants because low pressure refrigerants have a higher tendency to leak compared to high pressure refrigerants. The automatic purge unit helps to remove any non-condensable gases that may accumulate in the system, which can lead to reduced efficiency and potential damage to the equipment. By continuously purging these gases, the unit ensures that the system operates at its optimal level and prevents any potential safety hazards.

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  • 40. 

    Shaft glands on a steam turbine are located:

    • Front and rear of turbine 

    • Wherever the shaft emerges from the casing or steam could leak 

    • Wherever air could leak out of the turbine 

    • Wherever oil can leak from the lubrication system 

    Correct Answer
    A. Wherever the shaft emerges from the casing or steam could leak 
    Explanation
    Shaft glands on a steam turbine are located wherever the shaft emerges from the casing or steam could leak. This is because the shaft glands are designed to prevent steam leakage from the turbine. By placing the glands at the point where the shaft emerges from the casing, any potential steam leakage can be effectively controlled and prevented.

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  • 41. 

    While inspecting the machine room, the compressor is cycling on and off, what is causing the compressor to cycle on and off? 

    • Refrigerant overcharge 

    • Refrigerant undercharge 

    • Compressor valves problems 

    • Non condensables in the system 

    Correct Answer
    A. Refrigerant undercharge 
    Explanation
    The compressor is cycling on and off because of a refrigerant undercharge. When there is not enough refrigerant in the system, the compressor does not receive enough refrigerant vapor to compress and circulate through the system. As a result, the compressor shuts off until it detects a need for cooling again, causing the cycling on and off.

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  • 42. 

    As an RMO running a reciprocating chiller, you notice oil foaming the sight glass.  The cause for this condition could be:  

    • A sudden drop in crankcase pressure 

    • A faulty crankcase heater 

    • Liquid refrigerant mixing with the oil in the off cycle 

    • All of the above 

    Correct Answer
    A. All of the above 
    Explanation
    The correct answer is "all of the above". This means that all three options mentioned in the question could be the cause for the condition of oil foaming in the sight glass of the reciprocating chiller. A sudden drop in crankcase pressure, a faulty crankcase heater, and liquid refrigerant mixing with the oil in the off cycle can all contribute to the foaming of oil in the sight glass.

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  • 43. 

    Packing glands on centrifugal pumps are typically made out of what types of materials?

    • Graphite impregnated rope or string 

    • Ceramic and carbon with rubber retainers

    • Centrifugal pumps do not need packing glands 

    • Stuffing box filled with grease 

    Correct Answer
    A. Graphite impregnated rope or string 
    Explanation
    Packing glands on centrifugal pumps are typically made out of graphite impregnated rope or string. This material is commonly used because it has good lubrication properties and can withstand high temperatures and pressures. It also provides a tight seal to prevent leakage of the pumped fluid. Ceramic and carbon with rubber retainers may also be used in some cases, but graphite impregnated rope or string is the more common choice. Centrifugal pumps do require packing glands to ensure proper sealing, so the option stating that they do not need packing glands is incorrect. A stuffing box filled with grease is not a typical material for packing glands on centrifugal pumps.

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  • 44. 

    Mechanical seals are typically made of:

    • Carbon and stainless steel 

    • Ceramic and carbon 

    • Ceramic and graphite 

    • Graphite impregnated rope or string 

    Correct Answer
    A. Carbon and stainless steel 
    Explanation
    Mechanical seals are typically made of carbon and stainless steel because these materials offer excellent durability and resistance to corrosion. Carbon is used for the seal faces because it has self-lubricating properties and can withstand high temperatures. Stainless steel is used for the other components of the seal, such as the springs and housing, because it provides strength and resistance to chemical attacks. The combination of carbon and stainless steel ensures a reliable and long-lasting seal in various industrial applications.

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  • 45. 

    The primary function of the steam eductors on the surface condenser is to:

    • Condense the steam

    • Create a vacuum

    • Separate the steam and air

    • Safety device only

    Correct Answer
    A. Create a vacuum
    Explanation
    The primary function of the steam eductors on the surface condenser is to create a vacuum. Steam eductors use high-pressure steam to create a low-pressure area, which helps in drawing out air and other non-condensable gases from the condenser. This vacuum is necessary for efficient condensation of steam and optimal performance of the condenser. By creating a vacuum, the steam eductors ensure that the pressure inside the condenser is lower than the surrounding atmosphere, facilitating the removal of air and enhancing the condensation process.

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  • 46. 

    When looking at a wiring diagram for a 20 ton split system, you would expect to find the following information.

    • The path that current takes through the system 

    • A point to point detail of how the wires are run 

    • A pictorial of component position 

    • Amp ratings for all loads 

    Correct Answer
    A. A point to point detail of how the wires are run 
    Explanation
    When looking at a wiring diagram for a 20 ton split system, you would expect to find a point to point detail of how the wires are run. This means that the diagram would provide a clear and specific description of how the wires connect and run throughout the system. It would show the starting point and ending point of each wire, as well as any junctions or connections along the way. This information is crucial for understanding the electrical connections and ensuring proper installation and troubleshooting of the system.

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  • 47. 

    What is the cooling medium of the cooling towers?

    • Air

    • Water

    • Air and water 

    • Fan 

    Correct Answer
    A. Air
    Explanation
    Cooling towers use air as the cooling medium. The purpose of a cooling tower is to remove heat from a system by transferring it to the surrounding air. Water is typically circulated through the tower, and as the water flows over the tower's fill material, it is exposed to the air. The heat from the water is then transferred to the air through evaporation and convection, cooling the water in the process. Therefore, air is the main medium used for cooling in cooling towers.

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  • 48. 

    Types of steam turbines include all of the following except:

    • Impulse steam turbines

    • Reaction steam turbines

    • Impulse reaction steam turbine

    • None of the above

    Correct Answer
    A. None of the above
    Explanation
    The correct answer is "none of the above" because all three types of steam turbines mentioned in the options are actually included in the types of steam turbines. Impulse steam turbines, reaction steam turbines, and impulse reaction steam turbines are all valid types of steam turbines. Therefore, none of the options listed are excluded from the types of steam turbines.

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  • 49. 

    The pressure in a pipe is 55 psi, there are 15 ft per floor.  How many floors are 

    • 5

    • 6

    • 7

    • 8

    Correct Answer
    A. 8
    Explanation
    The pressure in a pipe is 55 psi and there are 15 ft per floor. To determine the number of floors, we need to divide the pressure by the height per floor. So, 55 psi divided by 15 ft gives us approximately 3.67. Since we cannot have a fraction of a floor, we round up to the nearest whole number, which is 4. Therefore, the correct answer is 8 floors.

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Quiz Review Timeline (Updated): Jan 21, 2025 +

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  • Current Version
  • Jan 21, 2025
    Quiz Edited by
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  • Jan 30, 2020
    Quiz Created by
    Micperez

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