Commercial Refrigeration II Practice Exam

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• A healthy start winding test result would show:
• A flow control device that stops or allows the flow of a refrigerant in a refrigeration system based on an electric signal is called a
• Ultrasonic leak detectors locate refrigerant leaks by:
• Which of the following is an effect of small carbon particles inside the refrigeration system?
• Which combination of system parameters is typically observed when noncondensable gases are present in the refrigerant circuit?
• The contacts of a current starting relay are:
• After a system cleanup the system should be charged:
• What visual clue on a system can indicate the presence of a refrigerant leak?
• If a restriction clears up when the system is turned off and allowed to warm, the restriction was probably due to:
• Which condition is most consistent with an acidic oil found in a hermetic compressor, requiring action?
• Which refrigerant component prevents liquid refrigerant from returning to the compressor?
• A TEV overfeeding condition can be caused by which of the following sensor problems?
• Which statement best describes the flow characteristic of ball valves in refrigeration systems?
• What is the material inside the filter drier called?
• What is the main advantage of a pressure relief valve on a receiver compared to a fusible plug?
• What is a safer, non-brazing method for removing copper tubing connections when servicing equipment?
• The correct way to discharge a capacitor is:
• Why should the temperature inside the compressor be kept under 300°F?
• Which of the following is an example of baseline evaporator data?
• A safer alternative to debrazing components is to:
• Baseline condenser data point commonly used to assess inlet conditions is?
• How does accumulated dirt on the condenser coil affect system operation?
• When cleaning up after a compressor burnout, immediately after you recover the refrigerant, you should
• If the compressor oil on a hermetic compressor is acidic, the next step is to change the:
• What is meant by a system's baseline data?
• To check for electrical potential at a switch or a load, technicians use a(n).
• Why is nitrogen used to purge the system before using the flushing solvent?
• A crankcase pressure regulator is designed to prevent compressor suction pressure from rising above what value?
• Which statement describes the parameters included in a baseline performance check?
• Noncondensable gases in the refrigeration system can cause which of the following other symptoms?
• A reciprocating compressor with leaking valves will operate with:
• One basic rule a technician must follow while searching for a leak is to:
• Which valve type is typically used for on/off control but is not considered an isolation valve?
• For new systems, when should baseline data be recorded?
• With three-phase compressors, a voltage imbalance of greater than ________ will cause the windings within a motor to generate heat beyond safe levels, leading to premature motor failure.
• Overdefrosting is caused by:
• Baseline condenser data includes what type of measurement?
• When recovering contaminated refrigerant, the high-side gauge should be connected to which line?
• Noncondensable gases in the refrigeration system can cause which of the following?
• Why is it necessary to have controls for maintaining a minimum high-side pressure on outdoor air-cooled condensers?
• Which component is typically installed in the discharge line leaving the compressor to separate oil from the refrigerant?
• Which option correctly identifies the two basic types of relief valves used on refrigeration systems?
• What is the default state of the contacts in a potential relay?
• What effect do noncondensable gases have on system performance?
• What does a crankcase pressure regulator do?
• A suction-to-liquid line heat exchanger typically:
• What breaks down to form poisonous gas in the presence of flames?
• With the compressor off, a technician compares the pressure of an air-cooled condenser with the pressure given on the PT chart for that refrigerant and temperature. The system pressure is considerably higher than the pressure indicated on the PT chart for that refrigerant and temperature. This indicates that:
• Which type of valve is NOT considered an isolation valve?
• Voltage drop across a switch indicates that:
• On run capacitors, any sign of bulging of its body is a sign of a(n) ________ capacitor.
• Where in the system is an oil separator installed?
• Which of the following is a possible cause of underfeeding the TEV?
• A winding that shows continuity to the compressor housing indicates:
• When reviewing condenser performance, baseline data should include which measurement?
• During normal defrost, the compressor is:
• If a compressor start winding resistance test shows OL, which conclusion is most accurate?
• An example of baseline condenser data is which temperature value?
• If a technician needs to check the refrigerant pressures on a system with a small charge:
• What property of POE oil used with HFC refrigerants necessitates liquid-line filter driers?
• What are the two basic types of relief valves used on refrigeration systems?
• Why are liquid-line filter driers required for all systems using HFC refrigerant?
• Which gas is used to purge the flush after flushing lines and coils?
• During a system cleanup, changing the oil in a hermetic compressor:
• What gas is used for leak testing after reassembly of the system?
• What is a common cause of overdefrost in a defrost cycle other than a refrigerant issue?
• To increase the operating superheat on a thermostatic expansion valve:
• RLA stands for which term in refrigeration systems?
• How do evaporators in medium-temperature refrigeration cases normally defrost?
• What type of systems normally use crankcase pressure regulators?
• To check the condition of the compressor's motor windings, a technician will need to measure the resistance of the windings using:
• One method of elevating system liquid pressure is to
• Turning the thermostatic expansion valve adjusting stem clockwise would have which effect on operating superheat?
• Baseline condenser data helps to establish a reference for which variable?
• Moisture in the refrigeration system can cause which of the following?
• If noncondensable gases are present in the system, which statement best describes the expected condenser pressure relative to the PT chart for the same refrigerant and temperature?
• A hot compressor with an infinite ohms reading between common and the other two terminals and a reading of 4.3 Ω between the start and run terminals most likely has:
• Which item is not typically included in a baseline performance check?
• Noncondensable gases can contribute to which performance issue?
• In a system with multiple evaporators, which device helps regulate evaporator pressure across the evaporators?
• Baseline condenser data typically includes which measurement?
• To manually defrost a frozen evaporator coil, technicians should:
• The capacitor testing function on many multimeters will NOT read correctly if:
• Moisture in the refrigeration system can also cause which of the following?
• What is the difference between a standard liquid line drier and a filter designed to be used following a flush procedure?
• A commonly observed sign that the filter drier is blocked is
• Before opening the compressor crankcase to take an oil sample, you should
• In a baseline condenser data log, which value is recorded?
• How can a technician determine when a filter drier is stopped up and needs changing?
• Suction line filters are generally designed
• Moisture indicators are normally part of which component?
• After a compressor burnout cleanup, what is the key oil maintenance step?
• What must technicians measure after a system cleanup to verify performance?
• When troubleshooting, small-capacity refrigeration systems:
• A discharge-line check valve primarily prevents which condition?
• Along with the refrigerant that is being discharged, compressors will discharge which of the following as it leaves the compressor?
• The advantage of ball valves over other types of manual refrigeration valves is that they:
• When debrazing a joint on a refrigeration system, often
• The inlet of the recovery pump should include?
• Many technicians use a(n) ________ to measure all electrical characteristics.
• Which of the following is another effect of small carbon particles inside the refrigeration system?
• Which trio of measurements is commonly used for electrical troubleshooting?
• After flushing the lines and coils, the flush should be purged out using which gas?
• What happens if you remove tubing before all the brazing material is molten?
• Which datum would be considered baseline when comparing condenser efficiency over time?
• Which statement correctly describes common desiccants used in driers?
• The contacts in a potential relay are typically in what state under normal operating conditions?
• Which systems use evaporator pressure regulators (EPR)?
• The coil of a potential relay used with small single-phase compressors should have a resistance of approximately:
• How is a compressor's rated load amp rating, RLA, determined?
• A bulging body on a run capacitor indicates which condition?
• Why is the filter drier important?
• When troubleshooting single-phase compressor motors, it is important that the technician:
• When should a technician record a system's baseline data?
• Which of the following is an example of baseline condenser data?
• Which component is designed to absorb moisture and contaminants from the refrigerant?
• During troubleshooting, if the superheat value of the refrigerant leaving an evaporator is higher than normal:
• Which condition is NOT considered when selecting a CPR valve?
• On a starting relay, the component can be tested to see if it is electrically acceptable using a standard ________ or capacitance meter.
• The run winding on a compressor has a resistance of 0 Ω. This indicates that:
• The coil of a current relay used with small single-phase compressors should have a resistance of approximately:
• To check the amount of electrical current a load is drawing, technicians use a(n):
• When installing a solenoid valve, which statement is correct?
• After a system cleanup, the system's performance should be verified by ________ and recording key system operating performance specifications.
• What does an evaporator pressure regulator primarily do?
• What are the three main circuit characteristics commonly measured to troubleshoot electrical circuits?
• Which parameter is an example of baseline condenser data?
• Which refrigeration device would most likely be installed in the discharge line leaving the compressor to prevent liquid refrigerant from draining from a raised condenser into the compressor head?
• If an ohmmeter test shows infinite resistance between the terminals of a compressor winding, this indicates:
• What is the proper method for charging a system after cleanup according to the discussed guidelines?
• During startup data collection for a condenser, which value is considered baseline?
• If an ohmmeter shows continuity but the resistance value is much lower than expected, this indicates:
• When checking the resistance of the compressor start winding, a reading of OL on the multimeter indicates what?
• An iced-up evaporator in a commercial freezer can be caused by which of the following?
• The current relay coil is wired in which location in the circuit?
• In a performance log, baseline condenser data is typically recorded as?
• Which parameter is used as a baseline data point for condensers?
• What is the advantage of using a pressure relief valve to protect a receiver instead of a fusible plug?
• During recovery, where should the low-side gauge be connected?
• You should flush the system:
• During troubleshooting, before documenting any of the system's pressures or temperatures it is best practice to:
• The starting relay contacts are described as normally open. What does this mean when the coil is not energized?
• Just before charging the system with clean refrigerant, you should
• When replacing or repairing any electrical components, always verify that the:
• When flushing the system, you should:
• When checking the resistance of the compressor start winding, a multimeter shows 3.1 Ω. This indicates:
• Why should technicians be cautious when taking an oil sample from a semihermetic compressor?
• Which instrument provides a visual indication of moisture condition in a refrigerant system?
• Baseline condenser data focuses on inlet condition measured as?
• If the liquid oil acid test kit cannot be used, indicators may be connected to the
• If a filter drier becomes clogged, what symptom would you expect?
• How can you tell when a filter drier is stopped up?
• Using heat-reclaim coils will help improve a building's overall:
• To isolate a semihermetic compressor from system pressure:
• Which of the following is a potential cause of overfeeding the TEV?
• What does a reading of 0 Ω on the run winding indicate?
• A suction superheat measurement higher than the manufacturers’ recommended setting indicates which condition?
• The coil of a current relay used with small single-phase compressors should have a resistance of approximately 0.1 Ω. Which of the following is closest to that value?
• How does an oil acid test kit indicate the presence of acid?
• Which procedure should be followed to safely isolate a semihermetic compressor from system pressure?
• In most commercial refrigeration systems, where is the excess refrigerant that is not being used stored?
• Which of the following is an example of baseline condenser data used in energy efficiency assessments?
• After diagnosing a defective compressor, the technician should:
• Which line is connected to indicators if the liquid oil acid test kit cannot be used?
• Which device is designed to separate and collect some of the oil in the discharge line and return it to the compressor's crankcase?
• If you try to remove tubing before all the brazing material is molten, the tubing will:
• Electrical components can be categorized into two groups:
• If the maximum continuous current rating is 20 A, what is the approximate RLA?
• After reassembling the system
• After a system cleanup, which evaporator value should be measured?
• After a capacitor is discharged:
• Electrical components can generally be divided into two groups:
• Oil separators return oil to which location in the compressor system?
• Which component’s failure is listed as a possible cause of an iced-up evaporator in the given material?
• What are the most common desiccant materials used in driers?
• The potential relay coil is wired:
• Which statement about a system's baseline data is true?
• The three major electrical defects in compressor motors that can be identified using an ohmmeter are:
• A suction superheat measurement lower than the manufacturer's recommended superheat setting indicates that:
• If suction superheat is lower than recommended, the most likely reason is: