What You Need to Know When Recovering R-410A - Yellow Jacket

YELLOWJACKET ®VOLUME 1, ISSUE 3UPDATEArticle reprinted withpermission from RSES JournalAugust 2003The high pressures involved with recoveringR-410A refrigerant requires using the properequipment to avoid serious injuryBY RALPH VERGARAThe U.S. Clean Air Act of 1990 and the MontrealProtocol call for the phaseout of HCFC-22 (commonlyknown as R-22). This has made it necessaryfor manufacturers to find a replacement for the standardR-22 refrigerant we all know so well.The replacements available today are HFCs R-407C orR-410A. Whether you work with R-410A or not, chancesare that most service technicians will work with it in thefuture.Since Carrier first introduced newly designed systemscharged with its version of R-410A called Puron in 1996,the industry has rapidly moved toward the use of therefrigerant. It is important to note that R-407C also iswidely accepted as a retrofit refrigerant for new designs,though it is used more frequently in Europe than inNorth America. It also is important to note that R-410Ais not to be used in retrofit applications.Many manufacturers of residential and commercialhvac systems are switching to or currently use R-410A intheir systems. The refrigerant is an HFC azeotropic mixtureof HFC-32 and HFC-125 and is now universallyaccepted in the hvacr industry. One more note is that theCopeland scroll compressor is the only compressordesigned to be used with R-410A.Safety firstBefore discussing the R-410A recovery process it is importantto address safety. The major difference between R-22and R-410A is the significantly higher pressures involvedwith using R-410A. Working with R-410A requires someadditional tools that you may not already have in yourservice vehicle.The pressure-temperature chart for R-410A comparesthe pressures of R-410A versus R-22 (see chart on the nextpage). This chart will show you how high the pressuresare that you will be working with. In general, R-410Apressures are 1.8 times higher than those of R-22.Your standard manifold set, hoses, recovery equipmentand recovery cylinder cannot be used when recoveringR-410A. The pressures you will see when working withAugust 2003 ~ RSES Journal

R-410A are too high for your standard equipment.Here are the items a technician will need to safelywork with R-410A.• Manifold set. The pressures encountered whileworking with R-410A require a manifold gauge set thathas a low-side gauge that reads up to 500 psig and a highsidegauge that reads up to 800 psig. This is higher thanyour standard manifold set.• Hoses. R-410A hoses and assemblies should be ULrecognizedand have a minimum of 800-psi working pressureand a 4,000-psi burst. This provides a five-to-onesafety factor.Temperature °FPressure PressureR-22 (psi) R-410A (psi)70 121.5 201.575 132.2 218.280 143.7 235.985 155.7 254.690 168.4 274.395 181.9 295.0100 196.0 316.9105 210.8 339.9110 226.4 364.1115 242.8 389.6120 260.0 416.4125 278.1 444.5130 297.0 474.0135 316.7 505.0140 337.4 537.0145 359.1 571.7150 381.7 607.6155 405.4 645.2Manufacturers also recommend that you use a ballvalve-typeconnection rather than an anti-blowback connector.An anti-blowback connector acts like a check valveand traps the refrigerant in the hose. This can make itdifficult to disconnect the hose under high-pressure conditions.A ball valve connector is much easier to controlunder high-pressure conditions.Although most R-410A units come with the standard1/4-inch fittings some manufacturers use 5 /16-inch accessfittings.When buying new hoses make sure that you buy acomplete hose assembly that has been recognized byUnderwriters Laboratories. Some hose manufacturers useUL-recognized hose but fail to have the complete assemblycertified for R-410A pressures.• Recovery equipment. Refrigerant recovery equipmentneeds to be R-410A compatible. To determine if yourexisting unit is approved, check the Air-Conditioning andSpecial equipmentis neededwhen recoveringR-410A to accommodatethe highpressures involved.Refrigeration Institute’s (ARI) website at www.ari.org orthe UL website at www.ul.com.Recovery units must be approved for Class V refrigerantsincluding R-407C, R-404A and R-507 and others perARI 740-98. For best performance with your R-410Arecovery equipment, it should have the following features:oversized condenser; oversized fan; crankcase pressureregulator (CPR) valve; and a high-pressure cutout switchrated for at least 510 psi.Recovery equipment also is available with a subcoolingfeature, which can be helpful when trying to recoverR-410A. Subcooling keeps the recovery tank pressuredown by ensuring that the refrigerant is fully condensedbefore putting it into the recovery cylinder. Keepingrecovery tank pressures down will increase the rate ofrecovery and reduce the wear and tear on recovery equipment.Subcooling also can be accomplished by submergingthe recovery cylinder in a bucket of ice.• Oversized condenser. Helps completely condensethe refrigerant and to keep the tank temperatures down.• Fan. The larger the fan and the more aggressive theSubcooling, whichkeeps recoverytank pressuredown by ensuringthat refrigerant isfully condensedbefore putting itinto the recoverycylinder, can beaccomplished bysubmerging thecylinder in abucket of ice.RSES Journal ~ August 2003

The push-pull recovery method works best when recovering more than 10 poundsof refrigerant.Liquid recovery is fast, but not all equipment can handle the process. Vapor recoveryis slower, but is the most common recovery method used.pitch of the blades, the more air is moved over the condenser.More airflow also keeps critical internal componentscool, increasing their life expectancy.• Crankcase pressure regulator (CPR). This devicewill ensure that you do not overwhelmthe recovery equipmentwith high pressures when workingwith R-410A. Units that use a CPRvalve do not require the technicianto throttle or regulate the flow ofrefrigerant to the recovery unit toprevent damage to the compressor.• Recovery cylinders. Youmust use a U.S. DOT 400 recoverycylinder when recovering R-410A.As mentioned above, a standardDOT 350 recovery cylinder will notsafely handle the high pressuresseen with R-410A. Your R-410Arecovery cylinders should be clearlymarked to prevent any chance ofmisuse. DOT 400 tanks should bereadily available at your localrefrigeration wholesaler.• High-pressure cutout. Ahigh-pressure switch rating higherthan 510 psi will keep the recoveryunit from prematurely relieving onhigh pressure when recoveringR-410A. Some manufacturers offerequipment with an override switchso that you can change over to ahigher-pressure switch when recoveringR-410A.The problem with having a dualswitch (550 or higher) is that anR-410A recovery cylinder (DOT400) and a standard recoverycylinder (DOT 350) are virtuallyindistinguishable. Using recoveryequipment with a high-pressureswitch rated at 550 with a standardDOT 350 recovery cylindercan cause the relief valve to blow.This can cause a dangerous situationfor you or your customers.Proper maintenance of thesepieces of equipment is critical foryour safety. Calibrate the gauges onyour manifold set before every useand annually check manifold setfor leakage. Check for nicks orcracks in your hoses. Make surethat the valve assemblies are notleaking and that the gaskets in yourhoses are in good shape.Check your recovery unit periodically to ensure that itis safe to use. If you notice degradation in the rate ofrecovery, check the built-in or external filter. Clearly markAugust 2003 ~ RSES Journal

all of your R-410A tanks and have them re-certified everyfive years.Recovery methodsOnce acquiring the proper equipment, it is time to getstarted with the recovery process. Although refrigerantproperties are different, the basic recovery process is thesame for R-410A and R-22.R-410A is much more dense than R-22 and has a highervapor pressure making it more difficult to recover. Youmust understand that the information in this article doesnot apply to all refrigerant recoveryequipment. The hook-up and recoveryinstructions will vary from manufacturerto manufacturer so be sure toread and understand all of the operationinstructions for your refrigerantrecovery unit.Although refrigerantproperties aredifferent, the basicrecovery processis the same forR-410A and R-22recovering R-410A refrigerant:• Always use the shortest hoses possible.• Using 3 /8-inch hose will greatly increase yourrecovery rates.• Use a heat gun to get refrigerant to boil off.• Use liquid recovery when possible.◆Ralph Vergara is the technical sales manager for RitchieEngineering. He engineers and designs commercial recoveryequipment and automotive refrigerant recovery, recyclingand recharging equipment for Ritchie.Click to all the tools you’ll ever need...www.yellowjacket.comAccept nothing less.New MicroLED UV LeakDetector pinpointsleaks at the speedof light.NewAccuProbe LeakDetector displays1 through 9 to zero-in onall refrigerants. Numberincreases closer youget to leak source.Which recovery method should youuse? Here are a few to choose from.• Push-pull recovery. Quicklyremoves the liquid refrigerant, but youmust change the hose connections torecover the vapor refrigerant after all ofthe liquid is removed. This method isnot recommended unless you are tryingto recover more than 10 pounds ofrefrigerant.• Liquid recovery. This is thefastest method of refrigerant recovery.However, not all recovery equipment iscapable of handling direct liquidrecovery. Check with the manufacturerof your recovery equipment to find outif your unit is capable of direct liquidrecovery and if there are any specialinstructions for direct liquid recovery.• Vapor recovery. This method isslower than liquid recovery, yet is themost common method used to recoverrefrigerant.Here are a few tips to follow whenNewDigital ElectronicCharging Scale foraccurate chargingwith anyrefrigerant.New DigitalLCD Vacuum Gaugedisplays atmosphere to25 microns so youknow systemis clean.Complete catalog and new productsnow on line, or call 952-943-1333.© 2003 Ritchie Engineering Company, Inc.Printed in U. S. A. CP-09/03NewPistol-GripInfrared Thermometerwith laser sightingmeasures -40°Fto 932°F.www.yellowjacket.com10950 Hampshire Avenue S.Bloomington, MN 55438-2623 USAPhone: 952-943-1333 • Fax: 800-322-8684Int’l Fax: 952-943-1605Reprinted from RSES Journal ~ August 2003