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Z51 REFRIGERATION TEST NEWEST TEST | ALL
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What is the order of components on the liquid line of reciprocating system from the condenser? ------CORRECT ANSWER---------------King valve, filter drier, solenoid valve, sight glass A high side float valve is used to maintain: ------CORRECT ANSWER-------- -------Constant level of refrigerant in the evaporator Picture of a pump ------CORRECT ANSWER---------------Ninety degrees reducing elbow, pump suction, pump casing, pump discharge, check valve Picture of a compressor ------CORRECT ANSWER---------------Oil charging port allows for the addition and removal of oil from the compressor A facility has failed to maintain water treatment to a refrigerant system ------ CORRECT ANSWER---------------Increase in the condenser pressure Which of these compressors is not a positive displacement type compressor? ------CORRECT ANSWER---------------Centrifugal Where is emergency power not required according to code? ------ CORRECT ANSWER---------------Data centers
What is the most widely used regulation book by operating engineers? ------ CORRECT ANSWER---------------EPA (Environmental Protection Agency) What type of refrigerant do you need FDNY approval for? ------CORRECT ANSWER---------------Propane A refrigeration system uses jet ejector to raise settled oil mixed with refrigerant to the oil pump. If a restriction in the refrigerant flow to the jet ejector develops: ------CORRECT ANSWER---------------There may be insufficient head to lift the oil An indirect, low temperature refrigerant system frequently uses glycol, instead of salt brine as the intermediate cooling medium. An advantage of this choice is: ------CORRECT ANSWER---------------The elimination of corrosion In relation to the suction pressure of a compressor, the reading on the oil pressure guage should read in the range, closer to: ------CORRECT ANSWER---------------15 to 30 PSI higher Non-condensable gases like air, oil vapor, or nitrogen travel through a refrigerant system with the refrigerant they usually accumulate in the: ------ CORRECT ANSWER---------------Condenser
Where must the Material Safety Data Sheets be located? ------CORRECT ANSWER---------------Where available to all employees The oil collected in an oil separator is generally: ------CORRECT ANSWER- --------------Returned to the compressor What is the function of gland steam? ------CORRECT ANSWER--------------- Seal the turbine rotor carbon rings Regarding the functioning of steam turbine, how is the water level controlled in the surface condenser hot well? ------CORRECT ANSWER----- ----------Operation of the recirculation and overboard valves The cause of the starved evaporator might be: ------CORRECT ANSWER--- ------------Low refrigerant charge A refrigeration engineer is running two centrifugal condenser water pumps in parallel. One of the pumps is at it's maximum pumping rate. If by mistake, the refrigeration engineer throttles back on the discharge valve of the other pump, the most likely effect will be: ------CORRECT ANSWER----- ----------A reduction on the total flow rate to the condenser The total amount of heat to be removed from the refrigerant in a condenser equals the heat picked up in the: ------CORRECT ANSWER--------------- Evaporator plus the heat of compression
The amount of electrical power used to operate a solenoid valve or a motor is measured in: ------CORRECT ANSWER---------------Volts Of the following, the most common metering device used today in reciprocating commerical refrigeration system under three tons capacity is: ------CORRECT ANSWER---------------TEV The purpose of wear rings in a centrifugal pump is to: ------CORRECT ANSWER---------------Prevent wearing of the pump housing and impeller You are the engineer running a 2000-ton (steam driven turbine) centrifugal refrigeration system, a refrigeration system supplies chilled water to a college campus with multiple buildings. While making rounds, you notice that the condenser water coming back down from the 9-cell cooling tower on the roof is at a temperature of 90F. You want to make an adjustment to bring the temperature of the condenser water down to 85F. Which one of the following immediate actions would you take? ------CORRECT ANSWER---------------Increase the speed of the cooling tower fans A water chiller is equipped with a reciprocating compressor, a thermostatic expansion valve, and an air cooled condenser. A restriction in the refrigerant liquid line would result in: ------CORRECT ANSWER--------------- High suction superheat A solenoid valve is used to allow a reciprocating refrigeration machine to adapt to the load on the system. The opening of the solenoid valve is caused by: ------CORRECT ANSWER---------------An electrical current creating a magnetic field
Thermal bulb is attached to the suction pipe between the evaporator coil and the compressor by an insulated line. Assume that the machinery room is at 85F. Break down of the insulation results in: ------CORRECT ANSWER---------------Flooding of the evaporator A chill water system uses refrigerant R-134. A leak in the evaporator shell may result in? ------CORRECT ANSWER---------------Set off the refrigerant monitor alarm What are the steam ejectors used for on the surface condenser of a system with a turbine? ------CORRECT ANSWER---------------To create a proper operating exhaust vacuum Water and moisture is a serious problem in a refrigerant system. How to avoid: - -----CORRECT ANSWER---------------Proper evacuation at the charging of the system The most important requirements for a good evaporator is that: ------ CORRECT ANSWER---------------It must have enough cooling surface to absorb the required heat While on duty, a refrigeration engineer notices that the suction line to the compressor and part of the compressor itself is frosted. Of the following, the most likely reason for this condition would be that: ------CORRECT ANSWER---------------There is not enough refrigerant in the system
While doing a routine line inspection, the engineer notices the bulk of the TXV on the floor. The refrigerant engineer should attach bulb at the: ------ CORRECT ANSWER---------------The outlet end of the coil To convert water at 32 degrees F to ice at the same temperature a refrigeration system must remove: ------CORRECT ANSWER--------------- The latent heat of fusion Efficiency of the refrigerant cycle is affected by the operations of the condenser. Of the following, a more efficient centrifugal compressor operation results from: ------CORRECT ANSWER---------------Lowering the condensing pressure The heat removed from the refrigerant in a condenser is: ------CORRECT ANSWER---------------Sensible and latent heat The refrigerant unit that you have been assigned to is being taken out of service for a major repair. You have been assigned to withdraw refrigerant for storage in suitable containers. According to the NYC Fire Code, you must ensure that the containers: ------CORRECT ANSWER---------------Are approved by the US Dept. of Transportation Which of the following best describes how the cylinder unloader works? ---- --CORRECT ANSWER---------------Keep in the suction valve opened while the compressor is in the return stroke
A centrifugal water pump is known as a lift pump when the: ------CORRECT ANSWER---------------The water supply to the pump suction inlet is below the pump level A TXV is used to maintain constant: ------CORRECT ANSWER--------------- Evaporator superheat The chilled water supply to the building is 55 deg F. If the chiller is being used for human comfort, should you be concerned about this, and why? ---- --CORRECT ANSWER---------------Yes, this temp is too high for human comfort purposes The packing gland of a centrifugal pump serves to: ------CORRECT ANSWER---------------The drip part of the packing gland gives evidence that there is water in the pump Capacity control of reciprocating hermetic compressor is typically achieved through: ------CORRECT ANSWER---------------Operation of the hot gas bypass valve The most important reason to sub-cool the refrigerant in the condenser is to ensure that: ------CORRECT ANSWER---------------A pure liquid refrigerant will enter the metering device A refrigeration engineer is logging readings from a reciprocating system. Compressor discharge temperature have dropped significantly and the suction line pressure is high. Which of the following that may be causing
this set of condition? ------CORRECT ANSWER---------------An expansion valve that is open too wide A low side float valve is used to maintain: ------CORRECT ANSWER--------- ------The level of the refrigerant in the evaporator Regarding fire safety, which ASHRAE refrigerant safety classification indicates no flammability and lower toxicity? ------CORRECT ANSWER------ ---------A When an expansion valve is operating properly, at the end of the evaporator will contain: ------CORRECT ANSWER---------------Only superheated vapor What information is not contained in a Material Safety Data Sheet? ------ CORRECT ANSWER---------------Cost of the material In a steam turbine, what is the function of the Kingsbury thrust bearing? ---- --CORRECT ANSWER---------------Maintain axial positioning of the rotor shaft A centrifugal water pump is considered to the fully primed when? ------ CORRECT ANSWER---------------The pump is full of liquid Copper tubing refrigerant lines must be installed for a new system. It is a well known service practice that tubing collapses at bends that must be
A rooftop water cooling tower is connected to a water pump in the building basement with a 12 inch diameter pipe. With the pipe turned off, a pressure gauge at the pumps inlet show a pressure of 140 PSIG the height of the water column, in feet, would be closest to: ------CORRECT ANSWER-------- ------- 323 What device protects the steam turbine from excessive speed? ------ CORRECT ANSWER---------------Governor assembly A refrigeration compressor has failed to turn on. The refrigeration engineer on duty verifies that the electrical circuit to the motor, including all switches and circuit breakers, is complete according to recommended service practice, the next item to be checked would likely be the: ------CORRECT ANSWER---------------Temperature and pressure controls Refrigerants are characterized by their physical properties included flashpoint, refrigeration effect, and others. Of the refrigerants in commercial and industrial, the one with the highest latent heat and refrigerant effect is: - -----CORRECT ANSWER---------------Ammonia Of what characteristics is ASHRAE refrigerant safety group classification system: ------CORRECT ANSWER---------------Flammability and toxicity Of the following, an example of an in line refrigerant cleaning system that may be used with a centrifugal compressor containing R-123 refrigerant is: ------CORRECT ANSWER---------------Recycling
Information about the physical and chemical properties of a hazardous material can be found in: ------CORRECT ANSWER---------------Material Safety Data Sheet What is the function of the turbine auxiliary oil pump? ------CORRECT ANSWER---------------Establish oil pressure during turbine start up The rupture disc for a low pressure centrifugal refrigeration machine is normally located on the: ------CORRECT ANSWER---------------Compressor suction What is the primary reason ribbed metal piping is used for electrical wires connected to the refrigeration system shown below? ------CORRECT ANSWER---------------It allows for flexibility and accounts for vibrations A multi cylinder reciprocating compressor uses cylinder unloaders to regulate capacity, what would not occur if some of the unloaders fail to operate when needed? ------CORRECT ANSWER---------------The chill water temperature will increase As shown in the picture below, the suction gauge of a condenser water pump reads 55 PSI. The pipe supplying the pump is 75 feet long and 12 inches in diameter. Approximately, how many gallons of water do you expect to obtain if the pipe is drained completely? ------CORRECT ANSWER--------------- 440
A reciprocating compressor cylinder has a 10 inches bore and 14 inches stroke. The volume of the refrigerant , in cubic inches, will be closer to: -----
- CORRECT ANSWER--------------- 1099 An electrically operated control requires 24 volts to operate. To change the available 110 volts to 24 volts ------CORRECT ANSWER--------------- Transformer In an indirect refrigeration system, of the following, the one that would not be used as a cooling medium for the building spaces being cooled is: ------ CORRECT ANSWER---------------R- 22 On a steam turbine, what would cause the atmospheric valve to open? -----
- CORRECT ANSWER---------------All answers (low vacuum in the surface condenser, leaking tubes in the surface condenser, dirty tubes in the surface condenser) You are the engineer running a 2000-ton (steam driven turbine) centrifugal rerigeration system, a refrigeration system supplies chilled water to a college campus with multiple buildings. Making your rounds, you notice that the condenser water pump #1 is making a lot of noise, the discharger guage reading of the condenser water pump is fluctuating drastically, and motor of the condenser pump #1 is running very hot. Which of the following would you take: ------CORRECT ANSWER---------------Turn on pump #2, shut off pump #1, and troubleshoot pump # Electric devices may be used to provide built in defrosting of refrigeration machine evaporator units. These devices are classified as? ------ CORRECT ANSWER---------------Resistors
The flash point of a compressor lubricating oil: ------CORRECT ANSWER--- ------------Should be higher than the compression temperature The primary way of achieving capacity control of a centrifugal compressor is by: ------CORRECT ANSWER---------------Adjustment of the impeller inlet pre-rotation vanes Cooling tower water requires the addition of chemical additives in order to: - -----CORRECT ANSWER---------------Reduce the formation of scale and algae In the picture below describes the equipment's function: ------CORRECT ANSWER---------------Remove non-condensables from the condenser The viscosity of lubrication oil is described by a number. A low viscosity number describes oil that: ------CORRECT ANSWER---------------Flows easily The most likely reason for refrigeration engineer to use a psychrometer is to measure: ------CORRECT ANSWER---------------Relative humidity level of the atmosphere The most important reason to use at least two compressors in a cascade system is to: ------CORRECT ANSWER---------------Avoid very high compression ratio for each compressor
What is the function of the vacuum breaker in the steam turbine? ------ CORRECT ANSWER---------------To achieve a faster cost down cycle An equalizer line on a TXV is used to: ------CORRECT ANSWER--------------
- Compensate for the pressure drop across the evaporator coil If R-134 accidentally touches a refrigerant engineer's skin, what first aid should be applied from the MSDS? ------CORRECT ANSWER--------------- Promptly flush the skin with water until all chemical is removed In a multi-stage centrifugal compressor, each stage: ------CORRECT ANSWER---------------Is identical in volume to the other stages A refrigeration engineer notices excessive cycling of the temperature control for a reciprocating compressor refrigeration unit. The crankcase temperature is high, the compressor discharge temperature is low, the suction line temperature is high. Of the following, the one that may cause this set of condition is? ------CORRECT ANSWER---------------Faulty compressor valves On an operating centrifugal compressor refrigerant unit, the refrigeration engineer notices that the compressor is short cycling. The unit is using a low side float valve as a metering device. Of the following requirements, this would indicate that: ------CORRECT ANSWER---------------The system is undercharged with refrigerant
The vessel depicted below may used in connection with ------CORRECT ANSWER---------------Refrigerant recovery The use of oil in the refrigeration machine is to ------CORRECT ANSWER--- ------------Reduce wear and friction in the compressor parts The following is a desirable property in a refrigeration ------CORRECT ANSWER---------------High latent heat The cooling medium for an evaporative condenser is: ------CORRECT ANSWER---------------Air and water The ratio of the actual pressure of water vapor in the atmosphere, to the saturated pressure of given temperature is? ------CORRECT ANSWER------ ---------Relative humidity The only refrigerant/temperature chart available to a refrigerant engineer lists the temperature is degrees Celsius. If the chart indicates a Celsius temperature of 4 degrees to equivalent to F ------CORRECT ANSWER------- --------39.2 degrees A refrigerant engineer was instructed to charge a 60 ton plant with R-134A refrigerant. The refrigerant engineer will most likely find the charging valve on the: ------CORRECT ANSWER---------------Low pressure side of the system
