R-410a Refrigerant Study Guide – Flashcards
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R-410A is a Refrigerant, also known as....?
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SUVA - 410A....... AZ-20......Puron
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The cylinder color code for R-410A is...?
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Rose
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HCFC-22 is scheduled for total phase out, by the year?
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2020
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Suction and Discharge pressures for R-410A are how much higher than R-22 Systems?
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40% to 70%
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What is Temperature Glide?
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A range of condensing and evaporating temperatures for one pressure.
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When handling Refrigerants, Technicians should?
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Wear approved eye protection and gloves/ Avoid loose fitting clothes.
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A full Nitrogen Cylinder has a pressure of...?
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2500 psig
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Nitrogen Cylinders should only be moved....?
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1) with a protective cap in place 2) with an approved Cylinder cart.
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Temperature Glide for R-410A is less than...?
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0.3 degrees F
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Why is R-410A a better choice than R-22 Refrigerant?
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R-410A is more efficient, uses less energy, and has a lower TEWI
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Due to it's higher Vapor heat Capacity, what can be said of the Discharge Temperature of R-410A when compared to R-22?
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Discharge temperature are lower.
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Systems using R-410A must use what type of lubricant?
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Polyol Ester Oil (POE)
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What can be said of Polyol Ester Oils?
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1) Can cause skin irritation 2) Is Hygroscopic..Draws moisture like a magnet 3) Has improved heat transfer characteristics over the mineral oils
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How would one remove moisture from a Polyol Ester Oil?
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Change the filter drier
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When installing a liquid line filter dryer on a R-410A system, the dryer must have a pressure rating of how much psig?
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600 psig
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What can be said of true Azeotropic Refrigerant?
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Will not fractionate.....Has no Temperature Glide.....Is a single component Refrigerant
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The closer a blend comes to being a true Azeotropic, what can be said of the Temperature Glide?
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The glide in temperature will decrease
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What can be said, if a Refrigerant blend is Zeotropic, or Near Azeotropic (NARM)?
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Leaks may cause a change in the composition of the blend.....It will have a temperature glide....It will Fractionate
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When charging a system with a blend that is Zeotropic, or Near Azeotropic (NARM), what must always be done?
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It has to be transferred from the cylinders as a liquid to avoid Fractionation.
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What is the negative result of a Near-Azeotropic blend Fractionalizing?
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This can cause the components of the blend to leak at uneven rates, due to the varying Vapor Pressures.
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What could be the result of a blend that has Fractionated, depending on the chemical make-up of the Refrigerant?
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The Refrigerant could be flammable.
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What must be be done to avoid Fractionation of a blended Refrigerant?
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The Refrigerant has to be charged as a blended liquid.
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What can be said of Sub-Cooled liquid stored in the Receiver?
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It will lose or gain sub-cooling, depending on the surrounding ambient conditions
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Why is R-407C a good choice for Retrofitting an R-22 Air Conditioning system?
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R-407C temperatures and pressure are similar to that of R-22........None ozone depleting
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What is the color code for R-407C?
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Chocolate
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What is the disadvantage of R-407C, as compared to R-22?
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It has a larger temperature glide.
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What must be done when calculating Super-Heat with R-407C?
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Super Heat must be done using a Dew Point value only.
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What must be done when calculating sub cooling with R-407C?
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Sub cooling must be done using a bubble point value only
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How is compression ratio calculated?
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Absolute Discharge Pressure divided by Absolute Suction Pressure
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R-407C, also has another disadvantage as compared to R-22. What would be this disadvantage?
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It will separate (Fractionate) into it's component Refrigerant.
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At what pressure does the Low Pressure Switch open on an R-410A?
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50 psig
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At what pressure does the High Pressure Switch open on an R-410A?
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610 psig, plus or minus 10 psig
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How is Refrigerant charged into an operating R-410A system?
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It has to be charged into the system as a blended liquid.......It has to be throttled into the Low Side to avoid compressor damage.
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Some R-410A cylinders are equipped with a Dip Tube. What is the purpose of the Dip Tube?
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It allows liquid to be removed with the cylinder in the upright position
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The manufacturers of R-410A equipment have redesigned their compressors. What was done with the compressors?
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The compressors all have increased wall thickness.
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All service equipment used on R-410A systems, must be capable of doing what?
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The equipment must be rated for higher pressures
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The flow area of a R-410A Metering Device is what in relationship to a R-22 Metering Device?
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About 15% smaller
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At what pressure on a R-410A Manifold Gauge does the High Side pressure go to?
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800 psig
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At what pressure on a R-410A Manifold Gauge does the Low Side pressure go to?
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250 psig with a 550 psig retard
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At what pressure does the Service Hoses have to be rated for, on an R-410A System?
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800 psig
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What is the Compressor Internal Pressure Relief (IPR) settings for an R-410A System?
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550 to 625 psig
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R-410A systems should not be stored at a temperature warmer than what?
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125 degrees F
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What type of leak detector is needed for working with R-410A Systems?
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One capable of sensing HFC Refrigerants.
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What can be said of R-410A Refrigerant if the system develops a leak?
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Remaining Refrigerant is OK to use, because R-410A has a low fractionation rate.
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What type of Recovery Cylinders must be used with R-410A?
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DOT 4BA 400...........DOT 4BW 400........both cylinders are rated at a 400 psig burst strength
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If the R-410A System uses a TXV Valve, what is the Proper method of charging the System?
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Sub Cooling
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If R-410A system uses a Capillary Tube or Fixed Metering Device, What is the proper method of charging the system?
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Super Heat
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Bubbles in a sight glass of R-410A, means the system is low on refrigerant...True or False?
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False!!!
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The Evaporator Coil used with R-410A Systems, needs to meet what requirements?
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UL approved design.........Service pressure rating of 235 psig
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If a large leak of Refrigerant occurs in a enclosed area, what should be done?
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Vacate and Ventilate the area
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What is the proper procedure when working on an Electrical Circuit?
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Power has to be shut off.......The panel should be locked and tagged....Technician carries the keys to the lock
