Commercial Refrigeration II Practice Exam

These questions are part of the practice quiz. Start practicing

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