Z-51 REFRIGERATION TEST With Correct Solutions 2024 Update
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Course
FDNY z51
Institution
FDNY Z51
Z-51 REFRIGERATION TEST With Correct Solutions
2024 Update
Efficiency of the refrigerant cycle is affected by the operations of the condenser. Of the following, a more
efficient centrifugal compressor operation results from: - Answer -Lowering the condensing pressure
The heat removed from the r...
Z-51 REFRIGERATION TEST With Co rrect Solutions 2024 Update Efficiency of the refrigerant cycle is affected by the operations of the condenser. Of the following, a more efficient centrifugal compressor operation results from: - Answer -Lowering the condensing pressure The heat removed from the refrigerant in a condenser is: - 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: - Answer -Are approved by the US Dept. of Transportation Which of the following best describes how the cylinder unloader works? - Answer -Keep in the suction valve opened while the compressor is in the return stroke In most semi -hermetic compressors, the suction vapor is used to: - Answer -Cool the motor The amount of refrigerant that flows through the orifices of an economizer is determined by the: - Answer -Differences between the high side and low side pressure The installation of an inline refrigerant cleaning system is advisable: - Answer -To remove impurities from the system The type of refrigerant system that is least likely to leak refrigerant into the building space that are being cooled: - Answer -Indirect system The suction pressure of a reciprocating compressor is 65 PSIG. The discharge pressure of this compressor is 120 PSIG. The atmospheric is 14.7 PSI. The compression ratio for the given condition is closest to: - Answer -1.69 A superheated vapor is: - Answer -Dry vapor above the saturation temperature A refrigerant engineer verifies that a condenser water pump is cavitating. Of the following, the most likely cause for this condition is: - Answer -A faulty cooling tower water level controller A centrifugal water pump is known as a lift pump when the: - Answer -The water supply to the pump suction inlet is below the pump level A TXV is used to maintain constant: - 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? - Answer -Yes, this temp is too high for human comfort purposes The packing gland of a centrifugal pump serves to: - 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: - Answer -Operation of the hot gas bypass valve The most important reason to sub -cool the refrigerant in the condenser is to ensure that: - 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? - Answer -An expansion valve that is open too wide A low side float valve is used to maintain: - Answer -The level of the refrigerant in the evaporator Regarding fire safety, which ASHRAE refrigerant safety classification indicates no flammability and lower toxicity? - Answer -A1 When an expansion valve is operating properly, at the end of the evaporator will contain: - Answer -Only superheated vapor What information is not contained in a Material Safety Data Sheet? - Answer -Cost of the material In a steam turbine, what is the function of the Kingsbury thrust bearing? - Answer -Maintain axial positioning of the rotor shaft A centrifugal water pump is considered to the fully primed when? - 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 made, the refrigerant engineer should use? - Answer -Level type tubing bender A reciprocating compressor is making a knocking sound during operation. If the refrigerant worn parts are not causing the knocking, what probably the cause? - Answer -Slugging of the liquid refrigerant In order for a refrigerant to become superheated, it must be heated in a section of the low side refrigerant line: - Answer -Where no liquid refrigerant is present All liquid has been recovered from a system to be overhauled, the system: - Answer -Should not be opened until all vapor has been recovered When a refrigerant engineer uses a portable compressor recovery unit to remove vapor refrigerant from a refrigeration system the removal rate of the refrigerant will gradually slow down because? - Answer -
The compressor efficiency is decreasing 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. During the course of making your rounds, you check the 9 cell cooling tower on the roof. You note the water level in all of the cooling tower cells is very low. Which one of the following immediate actions would take? - Answer -
Add additional make up water to the cooling tower
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