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A list of questions and answers related to HVAC systems and refrigerants. It covers topics such as vibration eliminators, safety glasses, refrigerant toxicity and flammability, control systems, copper tubing, customer service, and more. The document also includes information on ASHRAE Standard 34 and EPA refrigerant certification. The questions are multiple-choice, and the correct answers are provided. This document could be useful as study notes or exam preparation for HVAC technicians or students.
Typology: Exams
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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 - correct answer D: Parallel to the compressor crankshaft If you purchased ten filter-driers for $100.00, what was the price of each filter-drier? A: $100. B: $10. C: $1. D: $1.10 - correct answer B: $10. Which of the following jobs requires safety glasses? A: Driving a vehicle B: Extending a ladder C: Brazing D: Pulling thermostat wire - correct answer C: Brazing Which of the following instruments would typically be used to measure a vacuum? A: Micron gauge B: Thermostat C: Anemometer
D: Differential pressure gauge - correct answer A: Micron gauge ASHRAE Standard 34 deals with: A: Carbon monoxide safety levels B: Refrigerant quality C: Equipment room ventilation and alarms D: Refrigerant toxicity and flammability - correct answer D: Refrigerant toxicity and flammability ANSI/ASHRAE 34 published in 2001 and entitled "Designation and Safety Classification of Refrigerants".
D: Specific and latent heat - correct answer B: Latent and sensible heat 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 - correct answer D: Where any objects or obstructions are within 5 feet of the condenser fan 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 - correct answer A: Under an overhang where water may drain onto it A thermostat should be mounted: A: Approximately 5 feet above the floor B: Level C: On an inside wall D: All of the above - correct answer D: All of the above 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 - correct answer C: Increases A voltmeter is connected to a circuit:
A: In series B: In parallel C: Crossover D: Delta - correct answer 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 - correct answer B: In series 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 - correct answer C: Location of condensing unit disconnect 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 - correct answer C: With a swedge joint Which of the following oils is the most hygroscopic? A: POE oil B: Mineral oil C: Vegetable oil
D: Vacuum pump oil - correct answer A: POE oil 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 - correct answer A: Metal or glass containers 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 - correct answer D: All of the above 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 - correct answer C: Make the answer mathematically correct 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 - correct answer B: Decrease ACR soft copper tubing comes in: A: 20 foot lengths B: 30 foot sealed rolls C: 50 foot rolls D: 50 foot sealed rolls - correct answer D: 50 foot sealed rolls Typical ACR copper tubing flares are: A: Double flares B: 33 degree flares C: 45 degree flares D: 60 degree flares - correct answer C: 45 degree flares 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 - correct answer D: All of the above are correct What amount of oxygen is normally contained in air? A: 10% B: 15% C: 21% D: 25% - correct answer C: 21% 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 - correct answer A: The conditions above which a refrigerant gas cannot be condensed into a liquid Refrigerant cylinders should never be filled to over: A: 50% B: 65% C: 80% D: 90% - correct answer C: 80% 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 - correct answer B: Oxygen 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 - correct answer A: 186 watts The electrical resistance of a thermistor with a temperature increase. A: increases B: decreases C: remains unchanged D: varies by the 10th power - correct answer B: decreases 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 - correct answer C: Recovering Processing used refrigerant to bring it up to the standards of new virgin refrigerant is called: A: Recycling B: Reclaiming C: Recovering D: Restoring - correct answer B: Reclaiming The quality standard for new virgin refrigerant is: A: ARI 700 B: ARI 740 C: ARI 2030 D: UL 15 - correct answer A: ARI 700 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 - correct answer D: Low pressure control 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 - correct answer A: Static and total 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 - correct answer A: Inlet, outlet, oil line 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 - correct answer C: Back-seated 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 - correct answer A: Algae and scale Which of the following documents are required by law? A: Air balance report B: Charging chart C: Equipment list D: MSDS sheets - correct answer D: MSDS sheets
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 - correct answer D: All of the above 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 - correct answer B: Condenser 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 - correct answer D: Containing 5 pounds or less of refrigerant and having no service valves 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 - correct answer A: 40% to 70% higher than in an R-22 system R-410A systems use which of the following refrigerant oils? A: Mineral
B: Alkylbenzene C: Polyol ester D: Glycols - correct answer C: Polyol ester Carbon monoxide poisoning is often mistaken for: A: The flu B: Diabetes C: Blood disease D: Chronic low blood pressure - correct answer A: The flu 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 - correct answer D: All of the above 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 - correct answer C: 15 cubic feet of air per cubic foot of gas 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 - correct answer B: Lower R-410A is a refrigerant. A: CFC B: HCFC C: HFC D: POE - correct answer C: HFC 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 - correct answer D: All of the above are correct 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 - correct answer A: Difference between saturation temperature in evaporator and temperature of refrigerant leaving evaporator