Full file at raudone.info Technicians-3rd-Edition-Wirz-Test-Bank Answers to Commercial Refrigeration. Test Bank for Commercial Refrigeration for Air Conditioning Technicians 3rd for air conditioning technicians 2nd edition pdf commercial refrigeration for air. Commercial Refrigeration for Air Conditioning Technicians Click button below to download or read this book.
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Commercial Refrigeration for Air Conditioning Technicians 3rd Edition Wirz Solutions Manual - Free download as PDF File .pdf), Text File .txt) or read online for. Commercial Refrigeration for Air Conditioning Technicians for Air Conditioning Technicians [DOWNLOAD] PDF files, Read Online. Editorial Reviews. About the Author. Dick Wirz is a Master Electrician and Master HVACR Commercial Refrigeration for Air Conditioning Technicians 3rd Edition, site Edition. by.
Commercial Refrigeration for Air Conditioning Technicians 3rd Edition Wirz Solutions Manual
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What are the causes and how do you prevent flooding? What are the causes and how do you prevent slugging oil or refrigerant? What are the causes and how do you prevent flooded starts? What would you suspect on a burned out compressor that also had worn crankshaft bearings? Is the problem electrical or mechanical and why? Know how to size a TEV based on evaporator Btuh rating. What are the opening and closing forces on a TEV? If the bulb lost its charge what would happen and how would the evaporator pressures respond?
When replacing an existing cap tube with a different sized cap tube remember the following guidelines: Smaller I.
What is the function of a metering device? What are the forces that influence the operation of a fixed metering device? What are the forces that influence the operation of a TEV? If a TEV is starving, what are 3 things that must be checked to correct it?
If a TEV is flooding, what are 3 things that must be checked to correct it? What can cause a starving cap tube? How would you correct the problem? Why is superheat important? When will you get the best superheat reading?
What affects superheat? According to T. What precautions are necessary when mounting a TEV bulb to a vertical suction line?
Chapter 2 Review Questions
How does a TEV react to head pressure? How about a cap tube? How does a TEV react to evaporator load? How does a TEV react to a dirty or iced evaporator? What should you try first if a TEV is hunting? What should you do if you think a TEV is blocked or shut down internally? What is the temperature differential or swing of an air sensing refrigeration tstat? What is the benefit of a coil sensing tstat? How do you use the suction service valve to check compressor efficiency?
Why should you be careful about front seating the discharge service valve? What does an EPR do? What does a CPR do? What are the primary concerns when setting the low pressure control cut-in and cut-out? How does an oil safety control work? What two pressures does it measure? Why are current sensing relays sometimes used with oil safety controls? What is the maximum temperature drop across liquid and suction line filter- driers? What are the uses and restrictions concerning suction filter-driers?
Know what the numbers on a Sporlan filter-drier mean. Examples are: C, CS. What is a suction line accumulator used for and where is it located? Should it be used on any system that has a flooding problem? Why or why not? When is an oil separator required? Where is it located? Should an oil separator be used to correct a problem of oil loss due to it being trapped somewhere in the system because of improper piping?
What is a receiver used for and where is it located? What is a king valve and what is it used for? What is a heat exchanger used for and where is it located? What is a vibration eliminator and where is it located?
What do you have to keep in mind when installing a vibration eliminator? How would you know the maximum high pressure control setting on an outdoor unit? Be aware of their benefits as well as their limitations. Information about the exam and test taking tips: Do your review over several days or a week.
This also gives you an opportunity to make sure you answered all of the questions. Just make sure the person scoring your test knows which answer you have chosen to be the correct one.
This is enough time to finish the main part of the test questions. Do not rush in order to do the Extra Credit questions.
They do little good if you have not taken the time to concentrate on the first questions. I will give you a print-out so you can verify that my records on attendance, quizzes, and homework agree with your records. Highlight the answers after you have finished the exam. Reach-ins are designed cheaper so they are more affordable. Walk-ins are designed for longer term storage, while reach-ins are more for convenience.
Walk-ins have better wall insulation than reach-ins. Walk-ins have bigger compressors than reach-ins. Heat goes to cold; the heat in the box must transfer to the refrigerant in the evaporator. The compressor will be damaged by too high a suction temperature. Expansion valves are designed to lower evaporator temperatures.
Heat goes to cold; the heat in the condenser must transfer to the ambient air. The compressor is designed to only raise temperatures, not lower them.
To allow for a safety factor in case the condenser gets dirty. Between the discharge of the compressor and the inlet of the metering device. Between the outlet of the metering device and the inlet of the compressor.
Between the inlet of the evaporator and the outlet of evaporator. Only inside the compressor crankcase. The temperature of the refrigerant inside the evaporator tubing. The temperature of the air entering the evaporator. The temperature of the air leaving the evaporator. The temperature of the suction line leaving the evaporator.
Use an electronic thermometer on the inlet and outlet of the evaporator.
Commercial Refrigeration For Air Conditioning Technicians Solutions Manual
Compare the head pressure to the suction temperature. Subtract the evaporator inlet temperature from the evaporator outlet temperature. More b. Starving b. Flooding c. Flooded evaporator. Cap-tube evaporator. Multiple-circuit evaporator.
Stamped evaporator. Off-cycle defrost — requiring only an air sensing tstat. Off-cycle defrost — requiring special tstat and only one defrost heater.
Planned defrost — requiring an air sensing tstat and a defrost clock. Planned defrost — requiring an air sensing tstat, defrost clock, and electric heaters. The evaporator temperature increases and the suction pressure decreases. The evaporator temperature decreases and the suction pressure increases. Both evaporator temperature and suction pressure decrease.
Both evaporator temperature and suction pressure increase. Subtract evaporator temperature from the suction line temperature.
Add the evaporator temperature to the suction line temperature. Calculate the difference between air temperature entering and leaving the evaporator. Flooding b. Starving c. Operating properly d. A rise in temperature or a fall in pressure. A rise in temperature with a corresponding rise in pressure.
A fall in temperature. A rise in pressure. So the suction pressure does not go too low. So the liquid will travel up a vertical pipe. So the subcooling will be maintained. So the TEV will operate properly. Turns off the condenser fan until the head pressure rises. Slows down the flow of water through the condenser. Backs up refrigerant in the condenser. Subtract the temperature of the liquid line leaving the condenser from the condensing temperature b.
Add the temperature of the vapor line leaving the evaporator to the evaporator temperature c. Look at the high side gauge and find the temperature corresponding to the head pressure. Hire good apprentices to clean the units. Clean it yourself. Check the head pressure. Check the subcooling. Condenser split b. Temperature swing c.
Superheat d. Flooding the condenser by backing up refrigerant in the condenser b. Lowering the subcooling to maintain head pressure c. Raising the subcooling to raise the head pressure d. Lowering the suction pressure 10 psig below its design conditions. Raising the head pressure 50 psig highest design conditions. Slugging b. Starving d.
Overheating 54 What is the difference between slugging and flooding? Slugging is a little too much refrigerant; flooding is way too much refrigerant b. Flooding is a little too much refrigerant; slugging is way too much refrigerant c.
No difference they are the same 55 If the suction valves are broken, what is the most likely cause of this type of damage? Overheating Full file at https: Flooded start 57 What causes high motor heat on an air cooled compressor?
Broken discharge or suction valves b. Inadequate airflow across the compressor from the condenser fan c.
Low mass flow of suction vapor to cool the compressor motor d. Low ambient temperatures 58 What causes high motor heat on an suction cooled compressor?
Low ambient temperatures 59 How do you prevent flooding and slugging?
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Keep suction pressure up. Keep superheat at proper levels. Install a crankcase heater or pump-down solenoid. Maintain proper head pressures. Too fast a compressor start up b. Compressor short cycling c. Floodback d.
Refrigerant migration 61 How do you prevent flooded starts? Keep suction pressure up b. Keep superheat at proper levels c. An externally equalized TEV. An internally equalized TEV. A balanced port TEV.
Increases the flow of refrigerant. Decreases the flow of refrigerant. Maintains a steady flow of refrigerant. Adjusts the superheat up in the evaporator. Replace the TEV. Find the midpoint of the valve adjustment. Turn the adjuster out counter-clockwise 4 turns.No, because an oil separator does not return all the oil to the crankcase. To prevent evaporator starving and compressor motor overheating.
If the suction pressure of an R22 unit is 55 psig, what is the approximate evaporator temperature? What is volumetric efficiency? Keeps head pressure up during low ambient conditions. Low mass flow of suction vapor to cool the compressor motor d.