Refrigerant Machine Operator Test # 4

The correct answer is "relieved by another licensed refrigeration engineer". This means that the sole refrigeration engineer can only leave the building when another licensed engineer takes over their responsibilities. This ensures that there is always a qualified professional present to monitor and maintain the refrigeration system, ensuring its proper operation and preventing any potential issues or emergencies.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Radial clearance in reference to a steam turbine is the distance between the top of the rotating blades and the casing. This refers to the space or gap between the blades and the casing, allowing for thermal expansion and preventing any contact or interference between the blades and the casing during operation. It is important to maintain an appropriate radial clearance to ensure efficient and safe operation of the steam turbine.