HVAC Refrigerants and Lubricants Unit 16 Test
A refrigerant that is a direct one on one replacement for an existing CFC refrigerant is called a "retrofit" because it fits into place into a system without changing lubricants, desiccants, O-rings, hoses, or any other working parts.
The correct answer is 'False'.
ASHRAE Standard 18 is specifically dedicated to improving the safety of technicians working on cooling system, and it informs technicians about areas where technicians may experience danger and how to evaluate such circumstances.
The correct answer is 'False'.
All refrigerants are mediums used in a refrigeration system to pick up heat by evaporation at a higher temperature and pressure, and to give up heat by condensation at a lower temperature and pressure, but they are composed of several different compounds and components.
The correct answer is 'False'.
Azeotropic blends act as single components: are designed with numbers in the 500 series such as R-500 and R-502; and are always HCFCs.
The correct answer is 'False'.
Desiccants may protect a system from rust and freezing, but they are pretty much confined to removing moisture from a system.
The correct answer is 'False'.
HCFC refrigerants such as R-22 and R-123 are single component refrigerants composed of hydrogen, chlorine, fluorine and carbon and are being phased out by the year 2015.
The correct answer is 'False'.
Pressure/temperature charts and gauges for original refrigerants work with moist transition or alternative refrigerants.
The correct answer is 'False'.
Refrigerants are composed of either single components or binary or ternary blends of multiple-components refrigerants.
The correct answer is 'False'.
Select whether statements concerning characteristics an applications of ACR lubricants are true or false. An oil must have a certain capacity to absorb or not absorb water, and this is known as the oil's or its ability to absorb water.
The correct answer is 'False'.
Select whether statements concerning gauges, charts, and pressure/temperature relationships are true or false. Most refrigerants gauges also show the pressure/temperature relationships of all refrigerants and this permits a technician to read P/T relationships directly from the face of the gauge.
The correct answer is 'False'.
Store containers of oil in a closet.
The correct answer is 'False'.
The "retrofit" alternative is the ideal new refrigerant, but most new refrigerants are not one-on-one replacements because they require some modification to system components, system design or system charge.
The correct answer is 'False'.
The Clean Air Act Amendments of 1990 do not require the EPA to evaluate new refrigerants, but the EPA does have general guidelines which manufacturers may adopt.
The correct answer is 'False'.
The EPA program for refrigerant evaluation is called the Significant New Alternative Policy, better know as SNAP, and the only objective of the program is to make sure the alternative refrigerants have a zero ODP
The correct answer is 'False'.
The SAE K Standards cover retrofitting procedures and safety for all refrigerants used for automotive purposes.
The correct answer is 'False'.
The manifold gauge set is the technician's most valuable tool only when the gauges give true readings, and to assure this, the gauges need to be recalibrated if they do not return to one when no pressure or vacuum is present.
The correct answer is 'False'.
Use large containers instead of small ones.
The correct answer is 'False'.
Because a gas at a certain temperature will have a know pressure, gauges and charts that show pressure/temperature relationships have become valuable service tools.
The correct answer is 'True'.
CFC refrigerants such as R-11 and R-12 are single component refrigerants composed of chlorine, fluorine and carbon; but are no longer manufactured.
The correct answer is 'True'.
Do everything possible to avoid exposing synthetic oil to air because even the humidity in the air can affect performance.
The correct answer is 'True'.
For all desiccant service, original equipment or retrofit, follow the manufacturer's recommendations, and if the problems are present, call a filter manufacturer direct to get help.
The correct answer is 'True'.
HFC refrigerants such as R-134a and R-125 are composed by hydrogen, fluorine and carbon and many have been developed as interim or alternative refrigerants.
The correct answer is 'True'.
In all ACR systems that have a compressor, lubricants play two important roles: 1) Lubricant protect against wear by forming a thin, hydrodynamic film that keeps mechanical surfaces separated and thus protected. 2) Lubricants perform a sealing function by filling the gap between the piston and walls in a motor or compressor and help make the compression cycle more efficient.
The correct answer is 'True'.
Keep oil containers capped at all times when not in use.
The correct answer is 'True'.
Many refrigerant manufacturers provide free pocket size charts that a technician can quickly reference to relate a temperature reading to a corresponding pressure or a pressure reading to a corresponding temperature.
The correct answer is 'True'.
Mineral oils absorb only a small amount of water, and any excess water in a system using mineral oil will be carried around the system where it could cause corrosion or even freeze
The correct answer is 'True'.
Most desiccants used in ACR system are molecular "sieve" type in line driers that attract molecules into molecular holes and electrically hold them there.
The correct answer is 'True'.
R-134a has been adopted by the automotive industry as a replacement for R-12, and as of the 1995 model year, all major automobile manufacturers are using air conditioning systems with HFC-134a refrigerant in them.
The correct answer is 'True'.
R-134a, however, cannot be used as a "drop-in" replacement for R-12 in older automobile air conditioners because the 134a is not compatible with some lubricants used with the older systems, and O-rings and other components may have to be changed.
The correct answer is 'True'.
Refrigerants are identified by a numbering system established bu the American Society of Heating, refrigeration and Air Conditioning Engineers (ASHRAE) consisting of a number preceded by the letter R.
The correct answer is 'True'.
Select whether statements concerning desiccants, their characteristics and uses are true or false. Selecting a drier with molecular holes that are too large will pick up more water, but i may also pick up undesirable substances too.
The correct answer is 'True'.
Select whether statements concerning gauges, charts, and pressure/temperature relationships are true or false. Gauges for original refrigerants can be used with other refrigerants as long as a P/T chart for the replacement refrigerant is available because the pressure reading will still reflect the pressure, or vacuum, of the refrigerant at a given point in the system even though the P/T relationships will be different.
The correct answer is 'True'.
Select whether statements concerning guidelines for working with synthetic oils are true or false. Completely evacuate the system before charging the system with oil.
The correct answer is 'True'.
Some lubricants have anti wear (AW) compounds added as well as stabilizers, and undergo mechanical testing to determine the chemical interaction the lubricant has with the refrigerant and with metal surfaces.
The correct answer is 'True'.
The shape of a desiccant can also be important; and solid core or compact bead type sieves are recommended for retrofits, especially those switching to HFC-134a.
The correct answer is 'True'.
To calibrate gauges on a manifold set you would need to unscrew the bezel on the face of the gauge, locate the calibration screw and turn it so that the needle goes to zero.
The correct answer is 'True'.
UL Guidelines 2154 directs its attention to planning for cost effective retrofits and step by step guidelines for retrofitting systems large and small.
The correct answer is 'True'.
Under SNAP guidelines, independent testing groups work with the EPA to subject new substances to a variety of test, including, but not limited to: 1. Ozone depletion 2. Global warming potential 3. Flammability 4. Toxicity 5. Exposure potential 6. Economic and technical feasibility
The correct answer is 'True'.
Zeotropes or near azeotropic blends tend to change composition as they pass through the refrigeration cycle; are designated with numbers in the 400 series, such as R-409A and R-410A; and may be CFCs, HCFCs or HFCs depending upon what single components are used in them.
The correct answer is 'True'.
HFCs (134a and 404a/507) MUST have the mineral oil flushed out and replaced with ________________.
The correct answer is: AB
Most HCFC blends such as R-409A and R-410A will use the synthetic oil ___________ because it can be mixed with up to 20% MO which will not require extensive flushing when converting a CF/MO system to an HCFC blend.
The correct answer is: AB
Refrigerant can also be identified by an R, standing for refrigerant, and a number in what is called the ________________ ID system.
The correct answer is: ASHRAE
A refrigerant that cannot be separated into its single components by distillation and which behaves as a single-component refrigerant in application and service.
The correct answer is: Azeotrope
A blend containing two single-component refrigerants.
The correct answer is: Binary blend
A mixture of two or more single-component refrigerants.
The correct answer is: Blend
In a refrigerant blend designed to replace R-12 this point will mirror the saturated liquid phase readings of R-12.
The correct answer is: Bubble point
The temperature at which a blended refrigerant first starts to evaporate or the temperature where the first bubble of vapor appears at a constant temperature.
The correct answer is: Bubble point
This is th epoint at which the first bubble of vapor appears in a refrigerant blend at a constant pressure.
The correct answer is: Bubble point
With refrigerants other thank blends this is known as the "boiling point".
The correct answer is: Bubble point
______________________ continue to be used in older existing equipment even through production has stopped and these refrigerant will continue to provide technicians with valuable reference points for handling the interim and alternative refrigerants.
The correct answer is: CFCs
After going to the trouble of identifying an unknown refrigerant, the last thing you do after you evacuate and recharge the system is to assure that the next service technician won't have your problems: You will secure a tag to the system and the tag will show three things:
The correct answer is: Date, location, and type of system
The temperature at which consideration begins to form in a system using a blended refrigerant.
The correct answer is: Dew Point
With a blend designed to replace R-12 this point will mirror the saturated vapor phase of R-12.
The correct answer is: Dew point
A change in composition as a blended refrigerant changes phases through evaporation and condensation.
The correct answer is: Fractionation
The tendency of a blended refrigerant to evaporate over a range of temperatures, specifically, the difference between bubble point and dew point.
The correct answer is: Glide
The ________________ are the preferred alternative refrigerants of the future; technicians will quickly associate them with special lubricates and desiccants, "retrofitting" with them is a frequent option.
The correct answer is: HFCs
You are working on a system charges with blended alternative refrigerant and you discover that is has leaked enough to require a significant charge of refrigerant to get back to normal. A co-worker says you should repair the leak and charge the system again. What would you tell her?
The correct answer is: It would be easy to upset the balance of blended refrigerant, so the remaining charge should be evacuated, returned for reclaiming, and the system should be recharged with virgin refrigerant.
A refrigerant blend that can be separated into its single components by distillation, but exhibits performance characteristics very close to a single-component refrigerant; also called zeotrope.
The correct answer is: NARM
Some of you coworkers are discussing the old and new refrigerants, and one of them says the only difference is that the old refrigerants have ozone-depleting components in them. You know the statement creates a problem. What would you tell him?
The correct answer is: Old refrigerants are one component substances and that alternative and interim refrigerants are often binary blends containing two substances, or trinary blends containing three substances, and they will have different P/T relationships.
The ______________ oils first used with R-134a applications posed problems with absorbing water and separation, and in CFC applications proved to be incompatible with chlorine, so they are generally not being used.
The correct answer is: PAG
____________ oils are the oils of choice for alternative refrigerants because they are compatible with a wide range of alternative refrigerants.
The correct answer is: Polyolester
______________ is a popular CFC refrigerant for low pressure commercial and industrial air conditioners, particularly ones using certifugal compressors and one recommended alternative is R-123.
The correct answer is: R-11
______________ is a CFC refrigerant which is popular for domestic refrigerants, freezers, automobile air conditioners and commercial refrigeration and one recommended alternative is R-134A.
The correct answer is: R-12
_________________ is a popular HCFC refrigerant for residential and commercial air conditioners and freezers and one recommended alternative is R-410A
The correct answer is: R-22
________________ is a CFC refrigerant used for some residential and commercial air conditioners, and dehumidifiers and one recommended alternative is R-410B.
The correct answer is: R-500
_____________________ is a popular HCFC refrigerant for commercial freezers and refrigerants and one recommended alternative is R-408A.
The correct answer is: R-502
Upgrading older equipment with the parts or refrigerant needed to make it perform like a new system, or making system changes which allow a transition or alternative refrigerant to replace a CFC or HCFC.
The correct answer is: Retrofit
A blend containing three single-component refrigerants.
The correct answer is: Ternary blend
Able to turn, but not substain a flame.
The correct answer is: Weak flammable
You are servicing a refrigeration system and cannot identify thee refrigerant in the system. You know the system will have to be totally evacuated, the lubricant type will have to be verified, and service will have to start with __________.
The correct answer is: a virgin charge of refrigerant
Always follow specification of the compressor manufacturer when changing oil, and that includes the use of antiwear or other __________ that may be specified.
The correct answer is: additives
P/T charts and gauges along with temperature and pressure readings are valuable tools for ___________ ACR troubleshooting.
The correct answer is: all phases
Do not use _______________ to charge a system with refrigerant blend; most of this equipment has a small, restricted opening that will not facilitate the denser blend, and the timing devices are generally related tot he use of the original refrigerant.
The correct answer is: automatic charging equipment
Select the correct word(s) to complete statements concerning charging a system with a blend. After charging a system with a blend, the system should be tagged to alert later service technicians of the date of service, the type of refrigerant, and the total amount of ____________.
The correct answer is: charge
Even through the ASHRAE numbers have been around a long time, the advent of the Clean Air Act and refrigerant handling issues have caused a trend toward refrigerant ID by their basic ______________ so as to indicate whether refrigerants are CFCs, HCFCs, HFCs or something else.
The correct answer is: chemical composition
Technicians can generally ID refrigerant by the _________ of the cylinder it comes in.
The correct answer is: color
The gauge set is built around a manifold with a center access and two gauges, a ______________ for measuring low-side pressure and vacuum, and a ______________ gauge for measuring high-side pressure.
The correct answer is: compound gauge/high pressure
System refrigerant requirements are usually listed on the data plate of the _____________; the information may be by name or number with the amount of charge listed in pounds and ounces.
The correct answer is: condensing unit
The color codes for refrigerants may have significant variations in shade from one manufacturer, so while color provides a general reference, it's always best to rely on the information silk screened on the _______________.
The correct answer is: cylinder
Select the correct word(s) to complete statements concerning why pressure/temperature readings and relationships will be different. Temperature and pressure readings are ____________ in determining superheat and sub cooling which used to determine proper system charge.
The correct answer is: essential
The compound gauge set because extremely important when evacuating a system; the vacuum readings from a compound gauge provide visual verification of proper (or improper) ________________ levels.
The correct answer is: evacuation
Pressure/temperature charts and gauges provide quick references to trouble spots in a system, particularly at the ____________________ where design suction pressure is a critical reference, and the _________________ where discharge and liquid line pressure are a critical reference.
The correct answer is: evaportator/condenser
MO is not miscible with most alternative and many interim refrigerants, and if it is present in a system being retrofitted, the MO may have to be ______________ before the system is charged with the new refrigerant.
The correct answer is: flushed from the system
ACR lubricants are usually referred to by their ____________.
The correct answer is: initials
Because of the EPA Clean Air Act Amendments of 1990, technicians face expanded responsibilities in handling refrigerants and in selecting suitable _____________ or alternative refrigerants.
The correct answer is: interim
When a service tag lists all the information it should, a technician servicing the system at a later date can quickly determine not only the kind of refrigerant, but if the system has a ___________ that needs to be located.
The correct answer is: leak
The compound gauge is always on the __________, colored _________, and used to measure both positive pressures up to 250 psi and negative pressures, or vacuums from 0 in. hg (zero inches of mercury) to 30 gauge hg; no matter how the valves on the compound gauge are set, the gauge will always measure whatever vacuum or pressure the hose from that side is attached to.
The correct answer is: left/blue
In order for the components in refrigerant blends to not separate, the blend has to be charges into the system as a ________ or ____________ must be put into a charging cylinder and then the entire contents ____________ charges into the systems
The correct answer is: liquid/liquid/vapor
The _________________ HCFCs are one group of original refrigerants that will be slowly phased out while the industry develops alternative refrigerants with zero ODP.
The correct answer is: low-ODP
MSDSs (material safety data sheets) and other technical information should be available on request from the _______________.
The correct answer is: manufacturer
You have just followed a routine to verify the type of refrigerant in the system, but the pressure/temperature chart in your final cheek does not indicate a specific refrigerant. This should tell you that the system probably contains a mixture or there is _____________.
The correct answer is: not enough refrigerant to make a determination
MO is the lubricate of choice for _________ refrigerants, so adding or changing oil with R-12, R-22, R-500 and R-502 is just a matter of using the amount of MO recommended by the equipment manufacturer.
The correct answer is: original
Always follow recommended flushing procedures when removing MO from a system because the complete procedure may require several hours and ______________ flushing to effect total MO removal.
The correct answer is: repeated
The high pressure is always on the ____________, colored _________, and is used to measure only positive pressure up to 700 psi no matter how the values on the pressure gauge are set, the gauge will always measure whatever source the hose from that side is attached to.
The correct answer is: right/red
EPA regulations require that information silk screened include the name and chemical composition of the product, ________________, and warnings about use or handling.
The correct answer is: safety requirements
Select the correct word(s) to complete statements concerning the manifold gauge and its applications. The capacity to control pressures in the gauge manifold by manipulating the low and high-side valves gives the manifold gauge set _____________ applications.
The correct answer is: specific
The piece of equipment most often used in AC service is the manifold gauge set because it permits a technician to check __________ quickly and effectively.
The correct answer is: system operating pressure
Hoses used with manifold gauge sets should have low toss fittings to help technicians comply with "good faith" with regulations that forbid __________.
The correct answer is: venting refrigerant to the atmosphere
A __________ hose is often used to attach to the center access on the manifold.
The correct answer is: yellow
The 400- and 500-series numbers are reserved for refrigerant blend identification; the 400-series are _____________ and the 500-series are _____________.
The correct answer is: zeotropes/azeotropes
