NATE Final Exam #1
What is the nominal operating wattage of a one-quarter horsepower electric motor? A: 186 watts B: 100 watts C: 46 watts D: 373 watts
A: 186 watts
The operating pressures in an R-410A system are: A: 40% to 70% higher than in an R-22 system B: 10% to 15% higher than in an R-22 system C: Lower than in an R-22 system D: Approximately the same as in an R-22 system
A: 40% to 70% higher than in an R-22 system
The quality standard for new virgin refrigerant is: A: ARI 700 B: ARI 740 C: ARI 2030 D: UL 15
A: ARI 700
A cooling tower is treated for what two conditions? A: Algae and scale B: Algae and lime C: Scale and disease D: Algae and disease
A: Algae and scale
Superheat is: A: Difference between saturation temperature in evaporator and temperature of refrigerant leaving evaporator B: Difference between saturation temperature in evaporator and saturation temperature in condenser C: Difference between temperature measured at the compressor suction and compressor discharge lines D: A single temperature taken in the center of the evaporator minus the ambient air temperature
A: Difference between saturation temperature in evaporator and temperature of refrigerant leaving evaporator
An oil separator has which of the following lines or connections attached to it? A: Inlet, outlet, oil line B: Inlet and outlet C: Inlet and oil line D: None of these is correct
A: Inlet, outlet, oil line
Highly hygroscopic oils must be kept in: A: Metal or glass containers B: Tightly capped plastic containers C: An area out of direct sunlight D: A refrigerated space 50 degrees or cooler
A: Metal or glass containers
Which of the following instruments would typically be used to measure a vacuum? A: Micron gauge B: Thermostat C: Anemometer D: Differential pressure gauge
A: Micron gauge
Which of the following oils is the most hygroscopic? A: POE oil B: Mineral oil C: Vegetable oil D: Vacuum pump oil
A: POE oil
What two pressures can a pitot tube measure? A: Static and total B: Velocity and total C: Velocity and static D: Total and external static pressure
A: Static and total
The "critical temperature" and pressure of a refrigerant is: A: The conditions above which a refrigerant gas cannot be condensed into a liquid B: The conditions below which a refrigerant cannot be vaporized to a gas C: The conditions where even if a change of state were to occur, no latent heat exists D: The pressure at which no heat exists in the refrigerant therefore the temperature is absolute zero
A: The conditions above which a refrigerant gas cannot be condensed into a liquid
Carbon monoxide poisoning is often mistaken for: A: The flu B: Diabetes C: Blood disease D: Chronic low blood pressure
A: The flu
An outdoor air conditioning condensing unit should not be located: A: Under an overhang where water may drain onto it B: Within 4 feet of a hose bib connection C: Within 3 feet of an electrical disconnect D: All of the above
A: Under an overhang where water may drain onto it
If you purchased ten filter-driers for $100.00, what was the price of each filter-drier? A: $100.00 B: $10.00 C: $1.00 D: $1.10
B: $10.00
What component of a dehumidifier can be used to reheat the air after dehumidification has taken place? A: Evaporator B: Condenser C: Compressor D: None of the above
B: Condenser
As a warm air furnace raises the temperature of the air in a structure, the relative humidity of the space will: A: Increase B: Decrease C: Increase by the square of the change in temperature D: Remain the same
B: Decrease
A voltmeter is connected to a circuit: A: In series B: In parallel C: Crossover D: Delta
B: In parallel
Pressure relief valves are not to be piped: A: In parallel B: In series C: Facing up D: Within 12" of a wall
B: In series
The total heat contained in any substance is obtained by adding together its: A: Radiant and specific heat B: Latent and sensible heat C: Radiant and sensible heat D: Specific and latent heat
B: Latent and sensible heat
A tightly constructed building generally causes the pressure inside the building to be ______ than the pressure outside. A: Higher B: Lower C: The same D: None of these
B: Lower
Which of the following gases should never be used to pressure test for leaks? A: Nitrogen B: Oxygen C: Carbon dioxide D: None of these should be used for pressure testing
B: Oxygen
Processing used refrigerant to bring it up to the standards of new virgin refrigerant is called: A: Recycling B: Reclaiming C: Recovering D: Restoring
B: Reclaiming
The electrical resistance of a thermistor _________ with a temperature increase. A: increases B: decreases C: remains unchanged D: varies by the 10th power
B: decreases
The complete combustion of natural gas requires: A: 5 cubic feet of air per cubic foot of gas B: 10 cubic feet of air per cubic foot of gas C: 15 cubic feet of air per cubic foot of gas D: 20 cubic feet of air per pound of natural gas
C: 15 cubic feet of air per cubic foot of gas
What amount of oxygen is normally contained in air? A: 10% B: 15% C: 21% D: 25%
C: 21%
Typical ACR copper tubing flares are: A: Double flares B: 33 degree flares C: 45 degree flares D: 60 degree flares
C: 45 degree flares
Refrigerant cylinders should never be filled to over: A: 50% B: 65% C: 80% D: 90%
C: 80%
A three-position service valve located on the outlet of a receiver should be left in what position for normal operation with no gauges attached? A: Front-seated B: Mid-seated C: Back-seated D: Cracked
C: Back-seated
Which of the following jobs requires safety glasses? A: Driving a vehicle B: Extending a ladder C: Brazing D: Pulling thermostat wire
C: Brazing
R-410A is a ____ refrigerant. A: CFC B: HCFC C: HFC D: POE
C: HFC
As the pressure on a liquid rises, the temperature at which the liquid will boil: A: Varies B: Remains the same C: Increases D: Decreases
C: Increases
Which of the following is typically covered by local codes? A: Refrigerant type B: Maximum length of refrigerant lines C: Location of condensing unit disconnect D: Location of liquid and suction line service valves
C: Location of condensing unit disconnect
The purpose of converting psig to psia prior to calculating the compression ratio of a system is to: A: Make the answer come out as a positive number if the low side pressure is in a vacuum B: Make sure the answer is never negative C: Make the answer mathematically correct D: Allow for easy conversion to the metric system
C: Make the answer mathematically correct
R-410A systems use which of the following refrigerant oils? A: Mineral B: Alkylbenzene C: Polyol ester D: Glycols
C: Polyol ester
Removing refrigerant from a system and storing it in a cylinder without performing any testing or processing is called: A: Recycling B: Reclaiming C: Recovering D: Restoring
C: Recovering
What control would you use on a capillary tube or automatic expansion valve system to maintain the desired temperature? A: Dual pressure control B: High pressure control C: Thermostatic temperature control D: Low pressure control
C: Thermostatic temperature control
Hard drawn ACR tubing may not be used: A: In combination with soft drawn ACR tubing B: Without first annealing the tubing C: With a swedge joint D: On residential applications
C: With a swedge joint
ACR soft copper tubing comes in: A: 20 foot lengths B: 30 foot sealed rolls C: 50 foot rolls D: 50 foot sealed rolls
D: 50 foot sealed rolls
A heating and/or cooling load calculation is used to: A: Choose the correct equipment size B: Determine the correct duct sizes C: Determine the correct cfm to each room D: All of the above
D: All of the above
A thermostat should be mounted: A: Approximately 5 feet above the floor B: Level C: On an inside wall D: All of the above
D: All of the above
Carbon monoxide is the result of: A: Incomplete combustion B: Lowering the temperature of the flame C: Excessive fuel or a lack of oxygen D: All of the above
D: All of the above
The purpose of technician certification is to: A: Raise the competency level of technicians B: Decrease the number of poorly installed and improperly serviced systems C: Help consumers choose well-trained technicians D: All of the above
D: All of the above
A refrigerant classified as an "Azeotropic blend": A: Will not fractionate B: Behaves much like a single-component pure refrigerant C: Does not have a temperature glide D: All of the above are correct
D: All of the above are correct
Customers generally trust technicians who: A: Look them straight in the eye during conversations B: Genuinely listen to the customer's concerns C: Provide them with accurate information and options D: All of the above are correct
D: All of the above are correct
Type 1 EPA refrigerant certification is for systems: A: Containing 5 pounds or less of refrigerant B: Containing 8 pounds or less of refrigerant C: Containing 5 pounds or less of refrigerant and having fixed service valves D: Containing 5 pounds or less of refrigerant and having no service valves
D: Containing 5 pounds or less of refrigerant and having no service valves
Which of the following is not a suitable control for an air side economizer as used on a packaged unit air conditioning system? A: Enthalpy control B: Outside air thermostat C: Neither a nor b D: Low pressure control
D: Low pressure control
Which of the following documents are required by law? A: Air balance report B: Charging chart C: Equipment list D: MSDS sheets
D: MSDS sheets
Generally, vibration eliminators in piping should be installed: A: At a 45 degree angle B: At a 90 degree angle C: Perpendicular to the compressor crankshaft D: Parallel to the compressor crankshaft
D: Parallel to the compressor crankshaft
ASHRAE Standard 34 deals with: A: Carbon monoxide safety levels B: Refrigerant quality C: Equipment room ventilation and alarms D: Refrigerant toxicity and flammability
D: Refrigerant toxicity and flammability ANSI/ASHRAE 34 published in 2001 and entitled "Designation and Safety Classification of Refrigerants". • Class A signifies refrigerants for which toxicity has not been identified at concentrations less than or equal to 400 ppm; • Class B signifies refrigerants for which there is evidence of toxicity at concentrations below 400 ppm. • Class 1 indicates refrigerants that do not show flame propagation when tested in air at 21°C and 101 kPa; • Class 2 indicates refrigerants having a lower flammability limit of more than 0.10 kg/m3 at 21°C and 101 kPa and a heat of combustion of less than 19 kJ/kg; • Class 3 indicates refrigerants that are highly flammable as defined by a lower flammability limit of less than or equal to 0.10 kg/m3 at 21°C and 101 kPa or a heat of combustion greater than or equal to 19 kJ/kg.
An outdoor air conditioning condensing unit should not be located: A: In the sun B: On the side of the house C: Within 5 feet of a hose bib connection D: Where any objects or obstructions are within 5 feet of the condenser fan
D: Where any objects or obstructions are within 5 feet of the condenser fan
