Refrigerant Machine Operator Trivia Test #2

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

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 conductivity values among commonly used metals, making it an ideal choice for transferring heat efficiently in refrigeration systems. This allows for effective cooling and temperature regulation, ensuring the proper functioning of the refrigeration system.

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Refrigerant Machine Operator Trivia Test #2 - 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... see moreoperations, and safety practices, essential for professionals in HVAC and refrigeration. see less

2. WHAT IS A METHOD USED TO CALIBRATE A THERMOMETER?

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:

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:

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?

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:

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

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?

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:

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?

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:

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:

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:

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

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:

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?

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:

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:

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?

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:

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:

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?

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?

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?

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?

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:

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?

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?

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:

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:

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

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?

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?

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:

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?

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

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:

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:

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:

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:

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:

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

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:

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:

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

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. WHEN RECOVERING R-22, WHAT COLOR WOULD THE CYLINDER BE THAT YOU ARE STORING THE REFRIGERANT IN?

Explanation

The correct answer is YELLOW TOPS. When recovering R-22 refrigerant, the cylinder used for storing it should have yellow tops. This is because yellow is the designated color for cylinders used for storing R-22 refrigerant. The color-coding system helps to easily identify the type of refrigerant stored in the cylinder, ensuring proper handling and preventing cross-contamination.

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47. IF A LOW SIDE FLOAT IS BEING USED:

Explanation

A low side float is a device used in refrigeration systems to control the flow of refrigerant. It is designed to maintain a constant level of refrigerant in the evaporator by opening or closing a valve based on the level of refrigerant. When the refrigerant level is low, the float opens the valve to allow more refrigerant into the evaporator. Conversely, when the level is high, the float closes the valve to restrict the flow. Therefore, the correct answer is that a low side float will control the flow of refrigerant.

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

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

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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50. THE RUPTURE DISK IS ALWAYS PIPED INTO THE

Explanation

The rupture disk is always piped into the low side of the system. This is because the low side of the system typically operates at a lower pressure than the high side. Placing the rupture disk in the low side ensures that it will rupture and relieve pressure when the pressure in the system exceeds a certain limit, preventing damage to the system.

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51. WHAT TYPE OF PUMP IS THIS?

Explanation

This pump is a centrifugal chilled water pump.

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52. WHEN A SYSTEM DOES NOT HAVE UNLOADERS, WHAT IS NEEDED?

Explanation

When a system does not have unloaders, other capacity control methods are needed. Unloaders are devices that regulate the refrigerant flow in a system to match the cooling load. Without unloaders, the system would not be able to adjust its capacity based on the demand, leading to inefficient operation. Therefore, other capacity control methods such as variable inlet guide vanes, an economizer, or a solenoid on the liquid line are required to ensure optimal performance and energy efficiency in the system.

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53. A RECIPROCATING SYSTEM USING AN EVAPORATIVE CONDENSER, THE MUFFLER IS INSTALLED BETWEEN THE:

Explanation

In a reciprocating system using an evaporative condenser, the muffler is installed between the compressor and the evaporative condenser. The muffler is a device that helps to reduce noise and vibrations in the system. By placing it between the compressor and the evaporative condenser, it helps to dampen the noise and vibrations produced by the compressor before they reach the condenser. This helps to improve the overall efficiency and performance of the system.

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

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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55. WHAT IS 29.92" HG IN KPA

Explanation

The correct answer is 101.3. This is because 29.92" HG is a unit of pressure commonly used in aviation and meteorology to measure atmospheric pressure. It is equivalent to 101.3 kilopascals (kPa), which is the standard atmospheric pressure at sea level.

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56. THE MECHANISM SITTING ABOVE THE EVAPORATOR IS KNOWN AS

Explanation

The mechanism sitting above the evaporator is known as the purge unit.

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57. WHILE USING A HALIDE TORCH TO CHECK FOR REFRIGERANT LEAKS, IF THE FLAME WAS TO TURN YELLOW, WHAT HAPPENED?

Explanation

If the flame of the halide torch turns yellow while using it to check for refrigerant leaks, it indicates a restriction in the tube. This means that there is a blockage or obstruction in the refrigerant line, preventing the proper flow of refrigerant. This restriction can cause issues with the cooling system and may need to be addressed to ensure proper functioning.

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58. ASSUME THAT A NEW VALVE PLATE HAS BEEN INSTALLED WHILE THEY ARE REPAIRING A RECIPROCATING COMPRESSOR IN A REFRIGERATING PLANT. THE INSTALLATION OF A NEW VALVE PLATE WILL REQUIRE THE REPLACEMENT OF

Explanation

When a new valve plate is installed in a reciprocating compressor in a refrigerating plant, it is necessary to replace all valve plates, springs, and some valve seats. This is because the valve plate is a critical component that helps regulate the flow of refrigerant in the compressor. By replacing all valve plates, springs, and some valve seats, it ensures that the compressor operates efficiently and effectively.

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59. CONCERNING LEAKAGE, WHICH STATEMENT IS MOST CORRECT?

Explanation

Gate valves cause more leakage. This is because gate valves have a sliding gate that moves up and down to control the flow of fluid. When the valve is closed, there is a small gap between the gate and the valve body, which can result in some leakage. Globe valves, on the other hand, have a plug that moves perpendicular to the flow of fluid, creating a tighter seal when closed and reducing the chances of leakage. Therefore, gate valves are more prone to leakage compared to globe valves.

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60. WHEN AN EVAPORATOR IS NOT EQUIPPED WITH AN EQUALIZER LINE, YOU WOULD MOST LIKELY FIND:

Explanation

When an evaporator is not equipped with an equalizer line, it is most likely that a distributor would be present. A distributor is used to evenly distribute the refrigerant flow to the different evaporator coils. Without an equalizer line, the distributor helps to ensure that each coil receives the same amount of refrigerant, preventing any imbalance in cooling performance.

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61. OF THE FOLLOWING ONE OF THE PRIMARY REASONS FOR THE INSULATION OF A CRANKCASE BREATHER LINE IS:

Explanation

The primary reason for the insulation of a crankcase breather line is to prevent oil slugging in the compressor. Insulating the breather line helps to maintain the temperature of the oil and prevent it from condensing and accumulating in the compressor. This is important because oil slugging can cause damage to the compressor and reduce its efficiency. By insulating the breather line, the oil is kept at a consistent temperature, reducing the risk of slugging and ensuring the compressor operates effectively.

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62. AN OPERATOR VERIFIES THAT A CONDENSER WATER PUMP IS CAVITATING IN A REFRIGERATION SYSTEM EMPLOYING R-22 REFRIGERANT.  OF THE FOLLOWING THE MOST LIKELY CAUSE FOR THIS CONDITION IS:

Explanation

The most likely cause for the condenser water pump to be cavitating in a refrigeration system employing R-22 refrigerant is a faulty cooling tower water level controller. A faulty controller can cause the water level in the cooling tower to fluctuate, leading to inadequate water supply to the condenser. This can result in the formation of vapor bubbles in the pump, causing cavitation. Air leaks through the pump packing, operating at sustained high loads, or too long a period between pump servicing may also cause issues, but a faulty cooling tower water level controller is the most likely cause in this scenario.

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63. LATENT HEAT AND REFRIGERATION EFFECT ARE USUALLY LISTED AS REFRIGERANT PROPERTIES.  THE REFRIGERATING EFFECT IS ALSO ALWAYS A LOWER VALUE THAN THE LATENT HEAT BECAUSE THE:

Explanation

The refrigerating effect is always a lower value than the latent heat because the heat required to cool the refrigerant from compressor discharge to evaporative temperature is subtracted from the latent heat. This means that some of the latent heat is used to cool the refrigerant, reducing the overall refrigerating effect.

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64. DURING A HOT WEEKEND, AN RMO IS INSTRUCTED TO START AN ADDITIONAL RECIPROCATING MACHINE.  THE SEQUENCE OF ACTIONS ON START UP WOULD MOST LIKELY BE

Explanation

The correct sequence of actions on start-up during a hot weekend would most likely be to start the chiller and condenser water pumps first, followed by starting the cooling tower fans. After that, the next step would be to check the compressor oil levels, followed by checking that the valves are in the correct position. Finally, the machine can be turned on. This sequence ensures that the necessary components for cooling are activated first, and then the proper maintenance checks are performed before starting the machine.

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65. AN OPERATOR SUSPECTS THAT SHORTED MOTOR WINDINGS HAVE CAUSED THE MOTOR OVERLOADS TO TRIP.  IN ORDER TO INVESTIGATE THIS CONDITION, THE OPERATOR WOULD BE MOST CORRECT TO USE

Explanation

The operator suspects that shorted motor windings have caused the motor overloads to trip. To investigate this condition, the operator would be most correct to use an ohmmeter. An ohmmeter is used to measure the resistance in a circuit, and by measuring the resistance of the motor windings, the operator can determine if there is a short circuit present. If the ohmmeter shows a low resistance reading, it indicates a shorted winding. Therefore, using an ohmmeter would be the most appropriate tool for the operator to investigate the suspected condition.

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66. THE CONDENSER THAT USES AIR AND WATER FOR COOLING IS THE:

Explanation

The correct answer is EVAPORATIVE. An evaporative condenser uses a combination of air and water for cooling. It works by passing hot refrigerant gas through a coil, where water is sprayed onto the coil. The heat from the refrigerant causes the water to evaporate, which in turn cools the refrigerant. The cooled refrigerant then condenses back into a liquid state. This type of condenser is commonly used in air conditioning systems and industrial cooling processes.

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67. IN A CENTRIFUGAL THREE STAGE COMPRESSOR:

Explanation

In a centrifugal three-stage compressor, the pressure increases with each stage. This is because each stage adds more energy to the gas being compressed, resulting in a higher pressure output. Additionally, the impellers in each stage are of the same size, which allows for consistent compression and pressure increase throughout the stages. Therefore, both statements A and B are correct.

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68. WHAT SHAFT SEAL PREVENTS VAPOR FROM LEAKING OUT OF COMPRESSOR?

Explanation

A stuffing box is a type of shaft seal that prevents vapor from leaking out of a compressor. It is a traditional type of seal that uses packing material, such as braided rope or graphite, to create a tight seal around the shaft. This packing material is compressed against the shaft, preventing any vapor from escaping. Therefore, the correct answer is "STUFFING BOX."

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69. WITH AN INDUCED DRAFT COOLING TOWER, WHAT IS THE LOWEST TEMPERATURE ATTAINABLE FOR A COOLING TOWER?

Explanation

In an induced draft cooling tower, the lowest temperature attainable is when the dry bulb temperature is higher than the wet bulb temperature. The wet bulb temperature represents the lowest temperature that can be achieved through evaporative cooling. When the dry bulb temperature is higher than the wet bulb temperature, it means that the cooling tower is not able to cool the water to a lower temperature than the surrounding air. Therefore, the dry bulb temperature must be higher than the wet bulb temperature for an induced draft cooling tower.

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70. A CENTRIFUGAL CHILLER HAS A SUCTION PRESSURE OF 18" HG VACUUM AND DISCHARGE PRESSURE OF 6 PSIG.  WHAT IS THE COMPRESSION RATIO OF THIS UNIT?

Explanation

The compression ratio of a centrifugal chiller can be calculated by dividing the discharge pressure by the suction pressure. In this case, the discharge pressure is given as 6 PSIG and the suction pressure is given as 18" HG vacuum. To convert the suction pressure from inches of mercury to PSIG, we need to use a conversion factor. The conversion factor is approximately 0.491, so the suction pressure in PSIG is calculated as 18" HG vacuum * 0.491 = 8.938 PSIG. Therefore, the compression ratio is 6 PSIG / 8.938 PSIG = 0.671.

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71. WHAT IS THE CUBIC FEET IF A 20 FT LONG 6 FT VESSEL ON THE EVAPORATOR?

Explanation

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72. WHAT DOES CENTRIFUGAL COMPRESSOR GENERATE INSIDE?

Explanation

A centrifugal compressor generates high volume, low pressure inside. This means that it takes in a large volume of gas or air and compresses it to a lower pressure. This is achieved by converting the kinetic energy of the gas into potential energy through the use of rotating impellers. The gas is accelerated and then decelerated, causing an increase in pressure and a decrease in velocity. This type of compressor is commonly used in applications where a high flow rate is required, such as in HVAC systems or gas turbines.

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73. THE HEAT THAT BOILS OFF IN A CONDENSER IS:

Explanation

The heat that boils off in a condenser is latent heat. This is because latent heat refers to the heat energy required to change the state of a substance without changing its temperature. In the case of a condenser, the heat energy is used to convert a vapor or gas into a liquid state, without changing the temperature of the substance. Therefore, the correct answer is latent heat.

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74. BUBBLES IN THE SIGHT GLASS ARE MOST LIKELY CAUSED BY:

Explanation

Bubbles in the sight glass are most likely caused by a partially plugged filter/drier. The sight glass is used to observe the refrigerant flow in the system. If there are bubbles present, it indicates that there is a problem with the refrigerant flow, such as a restriction or blockage. A partially plugged filter/drier can cause the refrigerant to not flow smoothly, leading to the formation of bubbles in the sight glass.

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75. WHAT IS THE STATE OF REFRIGERANT AS IT LEAVES THE COMPRESSOR AND AS IT LEAVES THE CONDENSER:

Explanation

The state of the refrigerant as it leaves the compressor is superheated vapor, meaning it is in a gaseous state but at a temperature higher than its saturation temperature. As it leaves the condenser, the refrigerant is in a warm sub-cooled liquid state, which means it is in a liquid form but at a temperature slightly below its saturation temperature.

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76. SHELL AND COIL CONDENSERS HAVE THE ADVANTAGE OF:

Explanation

Shell and coil condensers have the advantage of having less chance of developing leaks. This means that compared to other types of condensers, shell and coil condensers are less likely to experience leaks, which can be beneficial in terms of maintenance and overall efficiency.

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77. A LOW PRESSURE REFRIGERATION SYSTEM HAS A PIN HOLE IN THE EVAPORATOR.  WHAT IS THE MOST LIKELY RESULT?

Explanation

If a low-pressure refrigeration system has a pinhole in the evaporator, the most likely result would be high head pressure. This is because the pinhole allows refrigerant to escape, leading to a decrease in the amount of refrigerant in the system. As a result, the compressor has to work harder to maintain the desired pressure, leading to an increase in head pressure.

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78. IF YOU WERE RUNNING THREE COMPRESSORS, WHICH BEST DESCRIBES THE STATE OF REFRIGERANT LEAVING THE THIRD EVAPORATOR COIL?

Explanation

When running three compressors, the refrigerant leaving the third evaporator coil would be in the state of superheated vapor. This means that the refrigerant has absorbed enough heat to completely vaporize, and then some additional heat has been added to raise its temperature above the saturation point. As a result, the refrigerant leaving the coil is in a gaseous state and is hotter than the saturation temperature for that particular pressure.

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79. COMPRESSOR MOTORS THAT OPERATE INSIDE THE REFRIGERANT ATMOSPHERE (ATMOSPHERIC):

Explanation

The correct answer is "ALL THE ABOVE". Compressor motors that operate inside the refrigerant atmosphere must use materials compatible with the system refrigerants. They must also be assembled in a clean atmosphere and kept dry. Additionally, these motors are not worked on in the field. Therefore, all of the given statements are true for compressor motors operating inside the refrigerant atmosphere.

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80. AN OPERATOR CONFIRMS THAT A CHILLER WATER PUMP IN A REFRIGERATING SYSTEM EMPLOYING R-123 IS CAVITATING, OF THE FOLLOWING, THE MOST LIKELY CAUSE FOR THIS CONDITION IS

Explanation

The most likely cause for the chiller water pump cavitation in a refrigerating system employing R-123 is the malfunctioning of the water make up float valve. A malfunctioning float valve can result in insufficient water supply to the chiller, causing low water levels and increased turbulence in the pump. This turbulence can lead to the formation of vapor bubbles, which collapse when they reach higher pressure areas, causing cavitation.

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81. WHAT IS THIS USED FOR?

Explanation

Recovery is the process of retrieving or extracting valuable materials or substances from waste or discarded products. It involves collecting and reusing materials that would otherwise be disposed of, reducing waste and conserving resources. This can include recovering materials such as metals, plastics, paper, and glass through methods like sorting, shredding, and melting. Recovery plays a crucial role in sustainable waste management and helps to minimize the environmental impact of waste disposal.

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82. THE FOLLOWING IS AN EXAMPLE OF AN "INLINE" REFRIGERANT CLEANING SYSTEM WHICH MAY BE USED WITH A CENTRIFUGAL COMPRESSOR CONTAINING R-123 REFRIGERANT IS:

Explanation

This question is asking for an example of an "inline" refrigerant cleaning system that can be used with a centrifugal compressor containing R-123 refrigerant. The correct answer is "REFRIGERANT RECYCLING." Refrigerant recycling is the process of removing impurities and contaminants from used refrigerant so that it can be reused. This is typically done through filtration and chemical treatments to remove moisture, acids, and other contaminants. This process helps to conserve resources and reduce waste by allowing the refrigerant to be reused instead of disposed of or reclaimed.

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83. CLEARANCE VOLUME:

Explanation

The clearance volume refers to the volume of space in a compressor cylinder that is not swept by the piston during the compression stroke. This volume affects the compressor capacity because it determines the amount of refrigerant that can be compressed and delivered by the compressor. A larger clearance volume will result in a lower compression ratio and lower compressor capacity, while a smaller clearance volume will result in a higher compression ratio and higher compressor capacity. Therefore, the clearance volume directly affects the compressor's ability to compress and deliver refrigerant.

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84. IF YOU HAD 38°F IN THE EVAPORATOR, WHAT SHOULD YOUR SUCTION PRESSURE BE FOR R-22

Explanation

The correct answer is 66 PSIG. The suction pressure in an R-22 system should be measured in PSIG (pounds per square inch gauge). PSIG refers to the pressure above atmospheric pressure. Since the question states that the evaporator temperature is 38°F, which corresponds to a saturation pressure of 66 PSIG on the R-22 pressure-temperature chart, the suction pressure should be 66 PSIG.

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85. A RMO IS LOGGING READINGS FROM A RECIPROCATING COMPRESSOR REFRIGERATING UNIT.  THE CRANKCASE AND COMPRESSOR DISCHARGE TEMPERATURE HAVE DROPPED SIGNIFICANTLY AND SUCTION LINE PRESSURE IS HIGH.  OF THE FOLLOWING THE ONE THAT MAY CAUSE THIS SET OF CONDITION IS:

Explanation

Faulty compressor valves can cause the crankcase and compressor discharge temperatures to drop significantly and the suction line pressure to be high. When the compressor valves are faulty, they may not be closing properly, leading to a decrease in compression efficiency and a decrease in temperature. This can result in a drop in crankcase and compressor discharge temperatures. Additionally, the faulty valves can cause a restriction in the flow of refrigerant, leading to an increase in suction line pressure. Therefore, faulty compressor valves are the most likely cause of this set of conditions.

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86. WHILE OPERATING AN R-12 RECIPROCATING SYSTEM, THE RMO NOTICED THE OIL FOAMING IN THE CRANKCASE, THIS CONDITION MOST LIKELY WOULD HAVE BEEN CAUSED BY: 

Explanation

A sudden drop in crankcase pressure can cause oil foaming in the crankcase of an R-12 reciprocating system. When the pressure in the crankcase drops suddenly, it can cause the oil to vaporize and create foam. This can be caused by factors such as a malfunctioning crankcase pressure regulator or a leak in the system. The foaming oil can lead to reduced lubrication and potential damage to the system.

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87. THE ACCESSORY POINTED OUT BY THE ARROW BELOW IS:

Explanation

The accessory pointed out by the arrow is a pressure gauge and globe valve. This can be determined by looking at the options given and identifying the correct combination. The arrow is pointing to a gauge-like instrument, indicating that it is a pressure gauge. The accompanying valve is a globe valve, as it is the only valve mentioned in the options. Therefore, the correct answer is pressure gauge and globe valve.

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88. WHEN A COMPRESSOR IS RUNNING FINE AT FULL FLOW AND YOU THROTTLE DOWN FLOW CAUSING THE COMPRESSOR TO STOP RUNNING NORMAL (SHORT CYCLE), WHY WOULD THIS HAPPEN?

Explanation

When a compressor is running fine at full flow and you throttle down the flow causing the compressor to stop running normally (short cycle), this could happen due to a low pressure cut out. The low pressure cut out is a safety feature in the compressor that shuts off the compressor when the pressure drops below a certain threshold. Throttling down the flow reduces the pressure, causing the cut out to activate and stop the compressor from running normally.

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89. WHEN CHARGING A CENTRIFUGAL SYSTEM THE POSITION OF THE VALVE IS:

Explanation

When charging a centrifugal system, the position of the valve is "back seated." This means that the valve is fully closed, with the disk pressed against the back seat. This position ensures that no fluid can pass through the valve, allowing for proper charging of the system without any leakage.

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90. THERE IS AN AUTOMATIC WATER REGULATING VALVE ON A RECIPROCATING CHILLER.  WATER IS ENTERING THE CONDENSER AT 88°F.  YOU KNOW THERE IS NO SCALE AND THE TUBES ARE NOT COVERED WITH FILM.  WHAT CAN BE CAUSING THIS CONDITION?

Explanation

The correct answer is "WATER VALVE STUCK OPEN". If the water valve is stuck open, it means that too much water is entering the condenser, which can cause the head pressure to be high. This can lead to inefficient cooling and potential damage to the chiller.

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91. SUPERHEATED VAPOR FLOWING INTO A RECIPROCATING COMPRESSOR PROTECTS THE COMPRESSOR PARTS AGAINST LIQUID INTAKE.  OF THE FOLLOWING, ONE OF THE PROBLEMS ASSOCIATED WITH SUPERHEAT IS THAT:

Explanation

Superheating refers to the process of heating a vapor above its saturation temperature. While superheated vapor is beneficial for protecting compressor parts against liquid intake, one of the problems associated with superheat is that it will decrease the capacity of the compressor and the refrigeration machine. This is because superheated vapor has lower density and specific heat compared to saturated vapor, resulting in reduced cooling capacity and efficiency.

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92. A HERMETIC COMPRESSOR IS OPERATING WITH A LOW REFRIGERANT CHARGE.  WHAT IS THE MOST LIKELY EFFECT THIS CONDITION WOULD HAVE ON THE COMPRESSOR?

Explanation

When a hermetic compressor is operating with a low refrigerant charge, it means that there is not enough refrigerant in the system. This can lead to inadequate cooling and lubrication of the compressor. As a result, the compressor would have to work harder to maintain the desired cooling capacity, causing it to operate at a higher temperature. Therefore, the most likely effect of a low refrigerant charge on the compressor is that it would operate at a higher temperature.

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93. WHEN WILL THE BTUs ABSORBED BY THE CONDENSING WATER BE THE GREATEST?

Explanation

The BTUs absorbed by the condensing water will be the greatest when the condenser temperature is high and the condenser water temperature is low. This is because a high condenser temperature means that the refrigerant is transferring more heat to the condensing water, while a low condenser water temperature allows the water to absorb more heat from the refrigerant. Therefore, the combination of high condenser temperature and low condenser water temperature maximizes the heat transfer and results in the greatest amount of BTUs absorbed by the condensing water.

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94. A CONDENSER IS 20' LONG AND 6' IN DIAMETER, WHAT IS THE VOLUME IN GALLONS IF 7.48 GALLONS IS 1 CU/FT?

Explanation

The volume of a cylinder can be calculated using the formula V = πr^2h, where r is the radius and h is the height. In this case, the radius is half of the diameter, so it is 6/2 = 3 feet. The height is given as 20 feet. Plugging these values into the formula, we get V = π(3^2)(20) = 180π cubic feet. Since 7.48 gallons is equal to 1 cubic foot, we can convert the volume to gallons by multiplying by 7.48. Therefore, the volume in gallons is 180π * 7.48 ≈ 4241.71. The closest answer choice to this value is 4227.

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95. A WATER REGULATING VALVE IS INSTALLED IN A WATER COOLED CONDENSER.  THE OPERATING FORCE ON THIS VALVE IS RESPONDENT TO:

Explanation

The operating force on a water regulating valve installed in a water-cooled condenser is responsive to the high side pressure. High side pressure refers to the pressure on the high-pressure side of the refrigeration system, which includes the condenser. The water regulating valve adjusts the flow of water through the condenser to maintain the desired high side pressure. By controlling the flow of water, the valve helps to regulate the condenser's cooling capacity and maintain optimal operating conditions for the system.

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96. Which of the following refrigerants is known for its low global warming potential (GWP) and is commonly used in new refrigeration systems?

Explanation

R-744, also known as carbon dioxide (CO2), is a natural refrigerant with a GWP of 1. It is considered an environmentally friendly alternative to traditional refrigerants with high GWP, such as R-22 and R-134a. R-410A is a hydrofluorocarbon (HFC) refrigerant with a moderate GWP, but it is still being phased out in favor of more sustainable options like R-744.

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97. A THERMAL BULB IS ATTACHED TO THE SUCTION PIPE BETWEEN THE EVAPORATOR COIL AND THE COMPRESSOR COVERED BY AN INSULATING LINE.  ASSUMING THE MACHINE ROOM IS 85°F, UNRAVELING OF THE INSULATION WOULD RESULT IN:

Explanation

Unraveling of the insulation on the thermal bulb would result in a flooded evaporator. The thermal bulb is responsible for sensing the temperature of the suction pipe, and if the insulation is removed, the bulb will be exposed to the warmer ambient temperature in the machine room. This will cause the bulb to sense a higher temperature than the actual suction pipe temperature, leading to incorrect control of the expansion valve. As a result, the expansion valve will remain open for longer periods, causing an excessive amount of refrigerant to enter the evaporator, leading to a flooded evaporator condition.

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98. WHEN THERE IS A 5 LB PRESSURE DROP ACROSS EVAPORATOR, YOU NEED AN EXTERNAL EQUALIZER LINE, WHAT HAPPENS IF IT DISCONNECTS

Explanation

If the external equalizer line disconnects when there is a 5 lb pressure drop across the evaporator, the evaporator would starve. This means that there would be a lack of refrigerant flow into the evaporator, leading to insufficient cooling and potentially causing the system to malfunction.

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99. REMOVING THE INSULATION ON THE SUCTION LINE, WITH THE ENGINE TEMPERATURE AT 85°F, WHAT WILL OCCUR?

Explanation

Removing the insulation on the suction line with the engine temperature at 85°F will result in excessive superheat. Superheat refers to the temperature of the refrigerant vapor above its boiling point. In this scenario, removing the insulation will cause the suction line to absorb more heat from the surrounding environment, resulting in higher temperatures and excessive superheat. This can lead to decreased cooling efficiency and potential damage to the system.

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100. A RMO NOTICES EXCESSIVE CYCLING OF THE TEMPERATURE CONTROL FOR A RECIPROCATING COMPRESSOR REFRIGERATION UNIT.  THE CRANKCASE TEMP IS HIGH, THE COMPRESSOR DISCHARGE TEMP IS LOW AND THE SUCTION LINE IS HIGH, OF THE FOLLOWING THE ONE THAT MAY BE CAUSING THIS SET OF CONDITIONS IS:

Explanation

The excessive cycling of the temperature control for the reciprocating compressor refrigeration unit, along with the high crankcase temperature, low compressor discharge temperature, and high suction line temperature, suggests a problem with the condenser operation, dirty tubes, or cooling water control. If the condenser is not operating properly, such as having dirty tubes or inadequate cooling water control, it can lead to inefficient heat transfer and poor refrigerant condensation. This can cause the compressor to work harder, resulting in the observed temperature conditions.

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COPPER USED IN REFRIGERATION SYSTEMS, LIKE IN HEAT EXCHANGERS,...
WHAT IS A METHOD USED TO CALIBRATE A THERMOMETER?
OF THE FOLLOWING CHARACTERISTICS OF REFRIGERANT, THE ONE THAT BEST...
WHEN DRY BULB IS 75°F AND WET BULB IS 75°F:
WHAT REFRIGERANTS ARE YOU NOT ABLE TO DUMP?
REGARDLESS OF SAFETY CLASSIFICATION OF THE REFRIGERANT IN USE, IN THE...
WHEN OPERATING A RECIPROCATING REFRIGERATION SYSTEM WITH A BELT DRIVEN...
WHEN YOU PLAN ON OVERHAULING A SYSTEM AND YOU HAVE RECOVERED ALL...
A REFRIGERATION UNIT IS MEASURED IN:
IF HAD TO INSTALL A SOLENOID VALVE TO A SYSTEM WHICH USES 110 VOLTS...
COMPOUND GAUGES CAN MEASURE:
THE REFRIGERATION UNIT WHICH YOU HAVE BEEN ASSIGNED TO IS BEING TAKEN...
ACCORDING TO THE NYC FIRE CODE CLASSIFICATION OF REFRIGERANTS, AMMONIA...
BECAUSE OF THE LATENT HEAT LOAD, REFRIGERATION MACHINE OPERATOR WAS...
THE ADVANTAGE OF FORCED DRAFT OVER NATURAL DRAFT COOLING TOWER IS:
AN ELECTRIC MOTOR THAT IS RATED AT 3 HP WILL?
THE SUCTION AND DISCHARGE VALVE IN A RECIPROCATING COMPRESSOR ARE...
AN OPERATOR SUSPECTS THAT A VERTICAL CHECK VALVE ON A DISCHARGE OF A...
IF UNLOADERS WERE TO FAIL IN THE UNLOADED POSITION, WHAT HAPPENS IN A...
WHEN THE TEMPERATURE AND THE LOAD INCREASE AND YOU NEED TO ADD ANOTHER...
OIL FLASHPOINT TEMPERATURE IN THE COMPRESSOR SHOULD BE:
FLOODED EVAPORATORS HAVE HIGH HEAT TRANSFER PER SQUARE FOOT, WHAT MAY...
HOW MANY BTUs WOULD BE REMOVED IN A 30 TON SYSTEM?
IF THE LOW PRESSURE CUTOUT CYCLES THE COMPRESSOR OFF, WHAT STARTS THE...
THE CYLINDER UNLOADER CONTROLS CAPACITY, IS THERE ANY OTHER FUNCTION...
SHELL AND TUBE CONDENSERS HAVE THE ADVANTAGE OF:
IN A 3 STAGE CENTRIFUGAL CHILLER, WHAT HAPPENS TO THE PRESSURE AS IT...
REGARDING FIRE SAFETY ANSI/ASHRAE, WHICH CLASSIFICATION INDICATES THE...
THE RATIO OF ACTUAL PRESSURE OF WATER VAPOR IN THE ATMOSPHERE TO THE...
ASSUMING THAT A REFRIGERATION PLANT USES A HORIZONTAL SHELL AND TUBE...
A FUSIBLE PLUG MELTS AT
THE ACCESSORIES ON THE LIQUID LINE ARE IN WHAT ORDER?
HOW LOW CAN CHILLER WATER TEMPERATURE BE?
REGARDING THE PUMP BELOW ELEMENTS A, B, C, D, AND E CORRESPOND TO THE...
IF YOU HAVE 62 PSI AT 35°F AND 70 PSI AT 45°F, WHAT WOULD...
WHEN A COMPRESSOR IS SAID TO HAVE A SAFETY HEAD THIS MEANS
THE METERING DEVICE USED IN A CONDENSER IS A HIGH SIDE FLOAT, THIS...
AN OIL WITH LOW VISCOSITY WOULD:
IN ADDITION TO REGULATING THE REFRIGERANT FLOW ACCORDING TO THE NEEDS...
WHILE DOING A ROUTINE INSPECTION, THE RMO NOTICED THE BULB OF THE TEV...
THE FOLLOWING MOST ACCURATE STATEMENT REGARDING COMPRESSOR MOTORS THAT...
THE DIVIDING LINE BETWEEN THE HIGH AND LOW SIDES OF THE...
AN OPERATOR NOTICES THAT A CENTRIFUGAL PUMP OPERATES SATISFACTORILY...
ELECTRIC DEVICES MAY BE USED TO PROVIDE BUILT IN DEFROSTING OF...
AN OPERATOR READS THE VALVE TAG ON A PRESSURE RELIEF VALVE AND NOTICES...
WHEN RECOVERING R-22, WHAT COLOR WOULD THE CYLINDER BE THAT YOU ARE...
IF A LOW SIDE FLOAT IS BEING USED:
IN RELATION TO THE SUCTION PRESSURE OF A COMPRESSOR, THE READING IN...
AN OPERATOR OBSERVES A READING OF 60°C ON A REFRIGERATING UNIT....
THE RUPTURE DISK IS ALWAYS PIPED INTO THE
WHAT TYPE OF PUMP IS THIS?
WHEN A SYSTEM DOES NOT HAVE UNLOADERS, WHAT IS NEEDED?
A RECIPROCATING SYSTEM USING AN EVAPORATIVE CONDENSER, THE MUFFLER IS...
THE MOST IMPORTANT REASON TO USE 2 COMPRESSORS IN A CASCADE SYSTEM IS...
WHAT IS 29.92" HG IN KPA
THE MECHANISM SITTING ABOVE THE EVAPORATOR IS KNOWN AS
WHILE USING A HALIDE TORCH TO CHECK FOR REFRIGERANT LEAKS, IF THE...
ASSUME THAT A NEW VALVE PLATE HAS BEEN INSTALLED WHILE THEY ARE...
CONCERNING LEAKAGE, WHICH STATEMENT IS MOST CORRECT?
WHEN AN EVAPORATOR IS NOT EQUIPPED WITH AN EQUALIZER LINE, YOU WOULD...
OF THE FOLLOWING ONE OF THE PRIMARY REASONS FOR THE INSULATION OF A...
AN OPERATOR VERIFIES THAT A CONDENSER WATER PUMP IS CAVITATING IN A...
LATENT HEAT AND REFRIGERATION EFFECT ARE USUALLY LISTED AS REFRIGERANT...
DURING A HOT WEEKEND, AN RMO IS INSTRUCTED TO START AN ADDITIONAL...
AN OPERATOR SUSPECTS THAT SHORTED MOTOR WINDINGS HAVE CAUSED THE MOTOR...
THE CONDENSER THAT USES AIR AND WATER FOR COOLING IS THE:
IN A CENTRIFUGAL THREE STAGE COMPRESSOR:
WHAT SHAFT SEAL PREVENTS VAPOR FROM LEAKING OUT OF COMPRESSOR?
WITH AN INDUCED DRAFT COOLING TOWER, WHAT IS THE LOWEST TEMPERATURE...
A CENTRIFUGAL CHILLER HAS A SUCTION PRESSURE OF 18" HG VACUUM AND...
WHAT IS THE CUBIC FEET IF A 20 FT LONG 6 FT VESSEL ON THE EVAPORATOR?
WHAT DOES CENTRIFUGAL COMPRESSOR GENERATE INSIDE?
THE HEAT THAT BOILS OFF IN A CONDENSER IS:
BUBBLES IN THE SIGHT GLASS ARE MOST LIKELY CAUSED BY:
WHAT IS THE STATE OF REFRIGERANT AS IT LEAVES THE COMPRESSOR AND AS IT...
SHELL AND COIL CONDENSERS HAVE THE ADVANTAGE OF:
A LOW PRESSURE REFRIGERATION SYSTEM HAS A PIN HOLE IN THE EVAPORATOR....
IF YOU WERE RUNNING THREE COMPRESSORS, WHICH BEST DESCRIBES THE STATE...
COMPRESSOR MOTORS THAT OPERATE INSIDE THE REFRIGERANT ATMOSPHERE...
AN OPERATOR CONFIRMS THAT A CHILLER WATER PUMP IN A REFRIGERATING...
WHAT IS THIS USED FOR?
THE FOLLOWING IS AN EXAMPLE OF AN "INLINE" REFRIGERANT...
CLEARANCE VOLUME:
IF YOU HAD 38°F IN THE EVAPORATOR, WHAT SHOULD YOUR SUCTION...
A RMO IS LOGGING READINGS FROM A RECIPROCATING COMPRESSOR...
WHILE OPERATING AN R-12 RECIPROCATING SYSTEM, THE RMO NOTICED THE OIL...
THE ACCESSORY POINTED OUT BY THE ARROW BELOW IS:
WHEN A COMPRESSOR IS RUNNING FINE AT FULL FLOW AND YOU THROTTLE DOWN...
WHEN CHARGING A CENTRIFUGAL SYSTEM THE POSITION OF THE VALVE IS:
THERE IS AN AUTOMATIC WATER REGULATING VALVE ON A RECIPROCATING...
SUPERHEATED VAPOR FLOWING INTO A RECIPROCATING COMPRESSOR PROTECTS THE...
A HERMETIC COMPRESSOR IS OPERATING WITH A LOW REFRIGERANT CHARGE....
WHEN WILL THE BTUs ABSORBED BY THE CONDENSING WATER BE THE GREATEST?
A CONDENSER IS 20' LONG AND 6' IN DIAMETER, WHAT IS THE VOLUME...
A WATER REGULATING VALVE IS INSTALLED IN A WATER COOLED CONDENSER....
Which of the following refrigerants is known for its low global...
A THERMAL BULB IS ATTACHED TO THE SUCTION PIPE BETWEEN THE EVAPORATOR...
WHEN THERE IS A 5 LB PRESSURE DROP ACROSS EVAPORATOR, YOU NEED AN...
REMOVING THE INSULATION ON THE SUCTION LINE, WITH THE ENGINE...
A RMO NOTICES EXCESSIVE CYCLING OF THE TEMPERATURE CONTROL FOR A...
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