Commercial Refrigeration II Practice Exam

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