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WorksheetsHVAC Intro and CORE
Total questions: 115
Worksheet time: 58mins
As refrigerant absorbs heat, it evaporates into a low-temperature vapor. What is this process referred to?
Compression
Condensation
Direct expansion
Subcooling
What are the dividing points between the low-pressure and the high-pressure sides of the system?
Evaporator and condenser
Compressor and the metering device
Filter-drier and sight glass
Suction line and discharge line
Where can you gain access for service?
Service valves, access valves, or process stubs
Thermostat terminals
Schrader cores only
Sight glass only
If a system is in operation, do you want to front-seat or back-seat a service valve?
Front-seat
Mid-seat
Back-seat
Crack open only
A PT chart shows the pressure–temperature relationship of what?
Air–water mixtures
Combustion gases
Refrigerants
Lubricating oils
What are the PT charts based on?
Ambient air properties only
Saturation properties for which a refrigerant evaporates and condenses
Compressor displacement only
Specific heat capacity at constant pressure
What must be present for the PT relationship to match?
Vapor only
Liquid
Oil
Superheated vapor
If a unit has had a leak or major component failure, what should you take?
Refrigerant pressure reading
Oil sample
Moisture indicator reading
Superheat measurement
What will finding and repairing leaks in a system help to conserve?
Refrigerant
Compressor oil
Filter-drier media
Condenser water
What should you NEVER flush field tubing with?
Dry nitrogen
Alcohol-based solvent
Liquid refrigerant
Clean, dry air
How do you dehydrate the system after a major repair?
Purge with nitrogen to 50 psi
Evacuate the system to a minimum of 500 microns
Run the system for 30 minutes
Heat the crankcase only
If there is a vacuum in the system, what should never be operated?
Air-cooled condenser fan
Thermostatic expansion valve
Hermetic compressor
Evaporator fan motor
What could burn the terminals inside the compressor?
Low ambient temperature
Electrical arcing
High superheat
Moisture in oil
What is one of the most important tools for an HVACR technician?
Recovery cylinder
Gauge manifold set
Thermal imaging camera
Tubing bender
What does the gauge manifold set measure?
Temperatures
Electrical current
Pressures
Airflow
What is pressure measured in?
Pascals absolute (Pa)
Pounds per square inch gauge (psig)
Inches of water column (in.w.c.)
Bar absolute (barA)
What is vacuum measure in?
Microns only
Inches of mercury (Hg)
Cubic feet per minute (cfm)
Kilopascals (kPa)
What do most high-pressure gauges range from?
0–300 psig
0–500 psig
0–800 psig
0–1200 psig
What color (usually) is the center port?
Blue hose
Red hose
Yellow hose
Black hose
What can the center port be used for?
Pressure measurement only
Recovery, evacuation, and charging connections
Only vacuum pump connection
Temperature monitoring
What does the EPA recommend that hoses be equipped with?
High-flow couplers
Quick-connects without valves
Low-loss fittings or valves that manually close or close automatically
Plain rubber gaskets
If you have low-loss fittings or valves, what does this minimize?
System pressure
Hose wear
Refrigerant loss
Oil contamination
Is a minor release of refrigerant when connecting or disconnecting hoses considered unlawful?
Yes, always unlawful
No, it is not considered unlawful
Only if the release exceeds a specified weight
Only when using a specific refrigerant type
What protects the earth from UV radiation from the sun?
Ozone layer
Troposphere
Carbon dioxide
Water vapor
What measures the ability of a substance to destroy ozone in the stratosphere?
Ozone depletion potential (ODP)
Global Warming Potential (GWP)
Acid deposition index
Photochemical smog index
Damaging the stratospheric ozone layer is increasing what two types of health issues for humans? Select all that apply.
Skin cancer
Cataracts
Asthma
Diabetes
Damaging the stratospheric ozone layer is also affecting the environment in what 2 ways? Select all that apply.
Decreased crop yields
Damage to marine organisms
Increase in freshwater supply
Soil salinity reduction
Based on evidence, what is depleting the ozone layer?
Chlorine-containing refrigerants
Nitrogen-based fertilizers
Vehicle carbon monoxide
Volcanic ash
What is the element of a CFC or HCFC that causes ozone depletion?
Chlorine
Hydrogen
Oxygen
Fluorine
How long can a single atom of chlorine last in the stratosphere and destroy ozone molecules?
120 years
12 months
5 years
300 days
Will chlorine found in CFCs or HCFCs dissolve in water/rain?
No
Yes
What are HFCs made up of?
Hydrogen, fluorine and carbon
Hydrogen, chlorine and carbon
Helium, fluorine and carbon
Hydrogen, fluorine and oxygen
Do HFCs contain chlorine and affect the ozone layer?
No, they do not contain chlorine and do not deplete the ozone layer
Yes, they contain chlorine and deplete the ozone layer
What does GWP stand for?
Global Warming Potential
General Weather Pattern
Greenhouse Warming Parameter
Global Weather Pressure
What is used as the baseline measurement for global warming potential and what is the value?
Carbon dioxide CO2 , value 1
Methane CH4 , value 10
Nitrous oxide N2O , value 5
Ozone O3 , value 2
What has the highest GWP? Select all that apply.
CFC refrigerants
HCFC refrigerants
HFC refrigerants
HC refrigerants
What has the lowest GWP?
HC and HFO refrigerants
CFC refrigerants
HCFC refrigerants
HFC refrigerants
Out of CFC, HCFC, HFC, HC and HFO, which make a good fit for HVACR equipment due to them being non-ozone depleting and low GWP?
HFO
CFC
HCFC
HFC
What has the highest ODP?
CFC
HCFC
HFC
HFO
Are HCFC more harmful or less harmful than CFC?
Less harmful due to hydrogen
More harmful due to fluorine
Equally harmful
More harmful due to chlorine
Even though HFCs have little/no ODP, they do have an affect on what?
Global warming
Acid rain
Ozone formation in the troposphere
Water pollution
Which 2 refrigerants have no ODP and are very low GWP?
HFO and HC
HCFC and HFC
CFC and HCFC
HFC and CO2
What should you never use as a refrigerant?
Propane cylinders
R-410A
Carbon dioxide cylinders
Ammonia (R-717)
What does azeotropic mean?
Contains 2 or more refrigerants
Contains a single refrigerant only
Changes composition during phase change
Has a high temperature glide
What does zeotropic or non-azeotropic mean?
Refrigerants that are mixtures of components with different boiling points
A refrigerant that boils at a single fixed temperature
A refrigerant blend that behaves like a single substance
A pure refrigerant with zero glide
What is temperature glide?
The blended refrigerant has different pressures for the same saturation temperature
The temperature difference between indoor and outdoor air
The rate at which compressor discharge temperature changes
The ambient temperature range for safe operation
What type of refrigerants use bubble and dew points to indicate condensing and evaporation?
Zeotropic and near-azeotropic blends
Pure refrigerants only
Azeotropic blends only
All refrigerants regardless of type
Which (bubble or dew points) are used when charging by condenser cooling?
Bubble point
Dew point
Which (bubble or dew points) are used for charging by suction or evaporator superheat?
Dew points
Bubble point
What is the pressure range for low-pressure refrigerants?
30 psig or lower
30 – 155 psig
155 – 340 psig
Over 340 psig
What is the pressure range for medium-pressure refrigerants?
30 – 155 psig
30 psig or lower
155 – 340 psig
Over 340 psig
What is the pressure range for high-pressure refrigerants?
155 – 340 psig
30 psig or lower
30 – 155 psig
Over 340 psig
What is the pressure range for very high-pressure refrigerants?
Over 340 psig
30 – 155 psig
155 – 340 psig
30 psig or lower
What kind of oil is most commonly used when retrofitting HCFC equipment to HFC refrigerants or when working with new systems?
Synthetic polyester oil
Mineral oil
Alkylbenzene oil
Polyvinyl ether oil
Can ester-based oils be mixed with other types of oils?
No
Yes
Before you add ester-based oil to a system, what must you do with the oil that is currently in the system?
Remove it
Test and leave it in place
Dilute it with mineral oil
Add dye to identify it
What does it mean when ester-based oils are hygroscopic?
Absorb moisture from the air
Resist absorbing water
Boil at a constant temperature
React with metal surfaces
What is the Montreal Protocol?
An international treaty that addresses ozone-depleting substances and their alternatives
A national law regulating indoor air quality only
A voluntary industry guideline on refrigerant labeling
A manufacturing standard for HVAC equipment
What is the US in the process of phasing out?
CFCs and HCFCs
HFOs and HCs
Ammonia and CO2
All refrigerant oils
What sets forth rules and regulations for refrigerant handling?
Section 608 Clean Air Act
OSHA Hazard Communication Standard
Montreal Protocol Technician Guide
EPA Energy Star Program
What does a Section 608 certification allow a technician to do?
Purchase or handle regulated refrigerants
Operate nuclear reactors
Install electrical wiring without a permit
Manufacture refrigerant cylinders
Does the Clean Air Act allow releasing an exempt refrigerant or a small amount of refrigerant (mixed with nitrogen) for leak detection?
Yes
No
What does SNAP do?
Identifies refrigerants with lower overall risks to human health and environment
Sets building electrical codes
Certifies HVAC technicians
Measures system pressure
Once all HCFCs are phased-out, where will you find HCFCs?
Only from recovered and reclaimed gas
From new production by manufacturers
From natural gas wells
As new stock from automobile AC service shops
Is it a violation to service a system that uses HCFCs after the phase out date?
Yes
No
What standard does reclaimed refrigerant need to meet before it can be resold?
AHRI Standard 700
ANSI Z535
ISO 9001
ASHRAE 34
Used CFC, HCFC and HFC refrigerants can only be used in the appliance or another appliance owned by the same ____________________.
Owner
Technician
Manufacturer
Contractor
Do self-contained or system dependent recovery devices use assistance from the appliance?
Self-contained
System dependent
What type of records must you keep if you are disposing of appliances that have 5-50 pounds of refrigerant?
Type of refrigerant recovered and quantities recovered each month, including quantities by type sent for reclamation or destruction
Names of customers served and service fees charged
Serial numbers of all tools purchased
Hours of technician training per year
What can happen if you top off one type of refrigerant with another refrigerant?
Void equipment warranty
Improve system efficiency
Damage equipment and cause injury or death
Create a compatible azeotrope that meets specifications
Ruin the refrigerant
If you are discarding disposable cylinders, what should you do with the refrigerant?
Recover
Vent safely to the atmosphere
Mix with nitrogen and release
Leave it in the cylinder
Who is the person that is responsible for ensuring that any CFC, HCFC or HFC refrigerant has been removed from appliances before being disposed of?
Final person in disposal chain
Original equipment manufacturer
First owner of the appliance
Utility company
Is venting refrigerant legal or illegal?
Legal
Illegal
What does recover mean?
Remove refrigerant, store in approved container and put into same system, another system with same owner or sent to be reclaimed
Clean refrigerant for reuse without meeting all reclamation requirements
Process refrigerant to new product specifications
Burn off refrigerant to eliminate emissions
What does recycle mean?
Remove refrigerant and clean it to be reused in equipment of same owner without meeting all requirements of reclamation
Remove refrigerant and store only
Process refrigerant to new product specifications
Vent to atmosphere after filtration
What does reclaim mean?
Processing refrigerant to new product specifications
Removing refrigerant for storage
Cleaning refrigerant for reuse without reclamation
Adding dye for leak detection
Any type of recovery or recycling equipment must be labeled with what?
EPA certification label
AHRI approval tag
Manufacturer serial plate
UL hazard label
What are the two types of recovery devices?
System-dependent (passive) and self-contained (active)
Oil-sealed (wet) and dry
High-pressure and low-pressure only
Manual and automatic
Which recovery device uses the assistance of the appliance?
System-dependent (passive)
Self-contained (active)
Both devices equally
Neither device
What two things will cause an increase in recovery time?
Long hoses
Appliance is located in low ambient temperature
Using short, large-diameter hoses
Warm ambient temperature
Should you have a separate cylinder for each type of refrigerant?
Yes
No
Why shouldn’t you mix refrigerants?
Might not be able to reclaim
Increases cooling capacity
Improves oil compatibility
Reduces evacuation time
Used refrigerant may not meet ______ standard so it can’t change ownership without being ____________.
AHRI standard; reclaimed
EPA standard; recycled
UL standard; vented
OEM standard; retagged
What might happen if you use the wrong type of leak detector with a flammable refrigerant?
Explosion
False alarms
Sensor burnout
No effect
How do you check for a small leak?
Electronic or ultrasonic leak detector
Listen for a hissing sound
Visual inspection only
Add more refrigerant and observe gauges
What are newly installed systems pressurized with for help with leak detection?
Dry-nitrogen
Oxygen
Compressed air
Carbon dioxide
Once you find the general area of the leak, what do you use to pinpoint the leak?
Soap bubbles
Infrared camera
Dye injection
Magnet
What should you do after a leak repair and before recharging the system?
Install new filter drier and complete a standing-pressure leak check
Immediately recharge the system
Bypass the drier and start the system
Add oil only
Do flammable refrigerants have or need to have odorants?
No
Yes, a strong odor is required
Only during shipping
Only for blends
What does dehydrating a system do?
Removes all water and water vapor
Removes all oil
Increases system pressure
Adds refrigerant
Before you dehydrate, the system should be ________.
Evacuated
Overcharged
Pressurized with refrigerant
Open to atmosphere
What would happen if you allow moisture to remain in a system?
Hydrochloric and hydrofluoric acids may form
The system will cool better
Moisture freezes into dry ice
The oil becomes nonconductive
What is the issue if a system does not hold a vacuum?
Leak
Overcharge
Faulty thermostat
Dirty filter drier
What can you tap a compressor with to release trapped refrigerant?
Rubber mallet
Steel hammer
Screwdriver handle
Wooden block
How do you know if dehydration is complete?
Vacuum gauge shows you’ve reached and held vacuum of 500 microns or less
Sight glass is clear
Suction line is cold
Bubbles stop in the oil
What does it mean if the pressure increases then stops then increases more?
More moisture in system
Non‑condensables have been removed
Vacuum pump is oversized
Gauge is defective
What does it mean if pressure rises steadily?
Leak
System is dry
Pump oil is new
Ambient temperature dropped
What should you do when pressurizing a system with nitrogen?
Charge through a pressure regulator and a relief valve in the downstream line
Charge directly from a nitrogen cylinder without regulation
Pressurize using oxygen to speed the process
Seal the system and heat it without monitoring pressure
When using more than one pressure relief valve should they be installed in a series or parallel?
Series
Parallel
Back-to-back
Alternating
What should you do if you find corrosion in a relief valve?
Replace it
Clean and reuse it
Paint over the area
Ignore it until the next service
If you are leak checking a system, should you pressurize the system with oxygen or compressed air?
Yes
No
What type of acid is formed if the refrigerant contains chlorine?
Hydrochloric acid
Sulfuric acid
Nitric acid
Hydrofluoric acid
What type of acid is formed if the refrigerant contains fluorine?
Hydrochloric acid
Hydrofluoric acid
Carbonic acid
Acetic acid
What do you need to review before working with any chemicals or multiple materials?
Manufacturer advertisements
Work schedules
Safety data sheets
Equipment warranty terms
Before you recover any flammable refrigerant, you want to ensure that the system and recovery unit are .
Pressurized
Grounded
Ventilated
Painted
What color marking is required on tubes and pipes in which flammable refrigerant flows through?
Red
Blue
Green
Yellow
If there is a large release of refrigerant in a contained area, what must you wear?
Dust mask
Self-contained breathing apparatus
Safety goggles only
Ear protection
What should you use to remove ice from sight glasses?
Alcohol spray
Hot water directly on the glass
A metal scraper
Compressed air
A recovery cylinder should be filled to no more than % of its capacity by weight.
50%
75%
80%
95%
What is used to determine the fill level of the recovery cylinder?
Mechanical float device
Electronic shut-off device
Measuring the cylinder weight
Pressure relief valve setting
Visual color indicator sticker
How often does a reusable container for refrigerant that is under high pressure need to be tested?
Annually
Every 3 years
Every 5 years
Only before first use
Can you use a disposable cylinder to recover refrigerant?
Yes
No
When you are shipping or transporting cylinders, you must attach a tag and label from the Department of .
Energy
Commerce
Transportation
Interior
Whose standards must shipping refrigerants follow?
Environmental Protection Agency
Department of Transportation
National Weather Service
Occupational Safety and Health Administration
What must be on the label?
Owner's name
Type of refrigerant
Date of manufacture
Cylinder color
