R 410A REFRIGERANT

User Manual: REFRIGERANT R-410A

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INTRODUCTION

Recently a new refrigerant, R-410A, has been formu-

lated and currently is being used in the HVAC/R

industry. It was developed primarily because the pro-

duction of R-22 is scheduled to stop soon. The

phaseout schedule for R-22, as mandated bythe

Environmental Protection Agency (EPA), will be dis-

cussed in more detail at the end of this article.

Although R-410A is specifically intended for use in

new air conditioning applications that traditionally

would have used R-22, other applications are also

possible,including low- and medium-temperature

refrigeration systems.

At first glance,the most notable difference between

R-410A and R-22 is the higher operating pressures

(approximately 50% higher on both the discharge side

and the suction side). For example, a high-efficiency

condensing unit using R-22 typically operates with a

suction pressure of about 68 psi and a discharge

pressure of about 250 psi at an outdoor temperature

of 95°F. With R-410A, the same unit will operate

under the same conditions with a suction pressure of

118 psi and a discharge pressure of 400 psi, as

shown in Figure 1 on the next page. (Note that in

most cases, equipment designed for R-22 cannot

use R-410A because of this difference in operating

pressures, so retrofitting an existing R-22 system is

normally not an option.)

When R-22 was first introduced as a replacement for

R-12 in residential air conditioning applications, man-

ufacturers and service technicians had to familiarize

themselves with the characteristics of this “new”

refrigerant. (R-22 operated at higher pressures and

was more efficient than R-12, but did not return oil as

well.) In time, R-22 became widely used and now has

served the HVAC/R industry well for over 50 years.

Today R-410A (which has had to pass strict safety

guidelines that R-12 and R-22 did not have to pass)

is becoming more popular, both because it is an HFC

(hydrofluorocarbon), and because its greater effi-

ciency allows for the design and use of smaller air

conditioning equipment.

R-410A is an azeotropic mixture of HFC-32 and

HFC-125. It has been developed as a long-term

replacement for R-22 in a variety of new air condi-

tioning and cooling equipment. R-22 is an HCFC,or

hydrochlorofluorocarbon, which means that it con-

tains chlorine, an element that is damaging to the

ozone layer. Because R-410A contains no chlorine

at all, its ozone depletion potential (ODP) is zero.

R-410A comes in rose-colored cylinders. The “rose”

color is PMS (Pantone Matching System) 507.

R-410A is expected to find widespread use in coming

years. Its benefits include significantly higher cooling

capacities and pressures. At 77°F, its density is 50%

greater than that of R-22, and its vapor pressure is

58% greater. Other advantages include a low toxicity

level, and recognition by Underwriters’ Laboratory

(UL) that it is virtually nonflammable (although it may

be combustible at elevated pressures, as discussed

later).

As with any refrigerant, there are certain safety pre-

cautions that the technician needs to understand and

observe. This article describes typical applications,

recycling/recoveryprocedures and equipment, and

precautions applicable to this new refrigerant product.

TYPICAL APPLICATIONS

Major applications for R-410A include unitary air

conditioning equipment, chillers,and commercial

refrigeration systems. In new unitary residential and

light commercial systems, R-410A has demonstrated

a5to 6% higher energy efficiency rating (EER) than

1

Refrigeration Service

Engineers Society

1666 Rand Road

Des Plaines, Illinois 60016

REFRIGERANT 410A

Information compiled by Frank Prah, CMS

©2001 bythe Refrigeration Service Engineers Society, Des Plaines, IL

Supplement to the Refrigeration Service Engineers Society.

620-108

Section 3 l

R-22. Its higher cooling capacity permits smaller,

more compact units to be used.

Because of the significantly higher pressures associ-

ated with R-410A, a typical compressor designed for

R-22 cannot be used with R-410A. As noted previ-

ously, this fact—along with other components in the

system that would need to be changed—renders the

refrigerant inappropriate for retrofit of existing R-22

systems.

Another important issue is the compatibility of the

compressor lubricant with the azeotropic R-410A

mixture.To ensure satisfactory operation and durabil-

ity, a polyolester-based lubricant that is miscible with

the refrigerant is recommended. Compressor manu-

facturers are continuing to test and recommend spe-

cific lubricants for use with R-410A. It is therefore

important to contact the compressor and/or equip-

ment manufacturer to reviewsystem lubricant

requirements. It is also important to review materials

with which the refrigerant will come in contact, includ-

ing motor windings in hermetic and semi-hermetic

compressors, gaskets, etc., for compatibility.

R-410A and R-22 are chemically compatible—which

means that they will not react or form other com-

pounds if accidentally mixed—but theywill form a

mixture that can be difficult to separate. At this time,

separation cannot be accomplished by any known

on-site recovery device or in the facilities of most off-

site reclaimers. Disposal of the mixture by incineration

is recommended.

RECOVERY OF R-410A

The capability and compatibility of recovery and

reclamation equipment are equally important consid-

erations for the service technician. Despite R-410A’s

negligible impact on the ozone, reclamation and

recycling are mandatory, and disposal must be con-

ducted in accordance with national, state or provin-

cial, and local regulations.

First and foremost, R-410A’s higher vapor pressures

mean that careful attention must be paid to the

design pressure rating of handling and storage

equipment, including recovery and storage cylinders.

For R-410A, a working pressure capability of at least

400 psi is recommended (this includes recovery

cylinders). Standard DOTrecoverycylinders rated for

350 psi should not be used. Use only DOTrecovery

cylinders rated for 400 psi or higher when recovering

R-410A.

Compatibility of the recovery equipment with the

components that makeup R-410A also is vital. In

addition to the guidelines provided by the manufac-

turer of the refrigerant, make sure you consult the

compatibility data supplied bythe recovery equip-

ment manufacturer.

Extraprecautions are required during storage and

handling. An important handling practice is the use of

liquid charging (rather than vapor charging) to mini-

mize compositional changes. Refrigerants in the -400

and -500 ASHRAE classification series should be

2

R-22

68 psi 250 psi

R-410A

118 psi 400 psi

Figure 1. Typical operating pressures

charged (put into the system) in a liquid state. Not all

manufacturers equip their cylinders with dip tubes.

Without a dip tube, the cylinder must be in the

inverted position (turned upside down) for liquid

charging. If you are charging on the high side, refrig-

erant can enter the system as a liquid, since there is

no danger of the refrigerant reaching the compressor

in liquid form and causing “slugging” damage. If you

are charging on the low side, meter the refrigerant as

it enters the system to vaporize before it reaches the

compressor.

In order to prevent the damage to equipment that can

be caused by charging with contaminated refrigerant,

cross contamination (the mixing of R-410A with other

refrigerants) should be avoided during recovery and

recycling. Recoveryequipment includes not only the

recovery/recycling machine itself, but also all equip-

ment that comes into contact with the refrigerant dur-

ing recovery and reclamation. This may include

hoses, storage cylinders, vacuum pumps, manifold

gauges, and scales.

To eliminate the possibility of cross contamination,

the technician should use recovery/recycling devices

with self-purging or evacuation features. Such equip-

ment contains special valves that work with internal

compressors to removerefrigerant bycreating a par-

tial vacuum in the tanks and hoses,thus allowing for

the complete removal and diversion of materials into

the recovery cylinder. Hoses, cylinders, and manifold

gauges should either be dedicated to R-410A or

evacuated after each recovery job. All equipment

should be clearly marked to indicate the formulation

for which it can be used, and all new cylinders should

be evacuated prior to the first use.

Proper maintenance of vacuum pumps,used to

remove non-condensable gases and moisture from a

system, is equally important. New (clean) oil specifi-

cally formulated for vacuum pumps should be used at

the start of each procedure. The oil should be

changed at intervals as recommended by the manu-

facturer,or more frequently if it takes on a milky or

cloudy appearance. An isolation valve is an absolute

necessity for checking system integrity. In addition,

wornO-rings and hoses should be replaced to

ensure minimal manifold leakage during evacuation.

Vacuum pumps should be capable of pulling a vacuum

of 300 to 500 microns.

Scales are sometimes used during recovery to pre-

vent tank overfilling. If the scale is equipped with an

automatic solenoid shutoff, it must be purged prior to

each use.

SAFETY PRECAUTIONS

ASHRAE has designated R-410A as A1/A1 on the

safety matrix shown in Figure 2. As you can see, the

“A1” rating denotes the safest refrigerants to handle.

In addition to the procedures discussed above

regarding the proper use of equipment and the

importance of avoiding cross contamination, there

are a few other safety precautions that the service

technician should note.

An R-410A system may be operating at over 600 psi

and not have the high-pressure safety switch open.

Carrier has a unit with the high-pressure switch set

at 610 psi. It resets at about 420 psi. The same

model has a loss-of-charge liquid-line switch that

opens at about 20 psi and resets at about 45 psi.

Low-pressure switches are also found on the suction

side. Low-pressure switches on Carrier equipment

using R-410A are usually set to open at about 50 psi

and close at about 100 psi.

Note: Heat pumps operating in the heating mode

also may have a vapor switch that cycles the outdoor

fan when the pressure is about 400 psi, and resets

when the pressure drops to about 310 psi.

3

Increasing toxicity

Increasing flammability

High

flame

Mild

flame

No

flame

Low toxicity

(TLV ≥400 ppm)

High toxicity

(TLV ≤399 ppm)

A3

A2

A1

B3

B2

B1

Figure 2. Safety matrix

Because it is heavier than air, R-410A vapors can

accumulate at ground level. If a large release of vapor

occurs, the vapor may displace the oxygen available

for breathing, resulting in suffocation. Although

smaller leaks pose no acute health hazards, expo-

sure to levels of more than 1,000 parts per million

(the same limit as R-22) can be harmful. Symptoms

of exposure to dangerous levels of R-410A include

dizziness, headache, confusion, cardiac irregulari-

ties, and loss of consciousness in extreme cases. If a

leak is present or suspected, a suitable leak detector

should be used to determine the need for ventilation

or respiratory protection.

R-410A expands significantly when heated. Expo-

sure of a container to direct sunlight or other heat

source can cause it to burst, resulting in serious

injury. Allied Signal recommends that its cylinders not

be allowed to exceed 125°F (52°C). Care also should

be taken to avoid damage to containers that could

cause them to leak or rupture. Storage near corrosive

chemicals or fumes or on damp floors should be

avoided.

Although R-410A is not flammable, it may become

combustible at elevated pressures in the presence of

large quantities of air. Containers and recovery/recy-

cling equipment should not be exposed to welding,

brazing, open flames,or high temperatures until thor-

oughly purged of all traces of liquid and vapor.

Recovery and recycling systems with self-purging

capabilities are invaluable for this purpose.

Other commonsense precautions for storing and

handling R-410A include:

ªusing personal protective equipment (e.g., side

shield glasses and safety shoes) when handling

containers

ªavoiding skin contact, which maycause frostbite

ªprotecting containers from damage, and hoses

from cuts or abrasions

ªstoring containers under a roof to protect them

from weather extremes

ªnever attempting to repair or alter containers or

valves.

As stated previously, the energy efficiency of R-410A

is allowing the design of smaller, more efficient air

conditioning equipment. By following the procedures

and noting the precautions provided in this article,

the technician can readily service systems using this

increasingly popular refrigerant.

R-22 PHASEOUT

The schedule for the phaseout of R-22 has been pre-

viously published, but may be accelerated at some

point. Currently the schedule is:

ª2010: New equipment designed for use with R-22

will no longer be manufactured.

ª2020: End of production of R-22 (after 2020, the

use of reclaimed and stockpiled R-22 may be

permitted).

SUMMARY

The following is a quickreview of some of the most

important points to remember when you are working

with R-410A:

ªNever vent R-410A (or any other refrigerant) to

the atmosphere.

ªR-410A is to be used with “new equipment

design” only (that is, it is not to be used in retro-

fits). If the cost of R-22 rises, R-407 may be used

in some cases to retrofit R-22 systems.

ªUse good piping practices when installing units

with R-410A. (Piping practices are similar to

those recommended for R-22 systems.)

ªR-410A operates at pressures 50 to 70% higher

than those of R-22. Be certain that servicing

equipment and replacement components are

designed to operate with this refrigerant.

ªR-410A cylinders are rose-colored (PMS 507).

ªRecovery cylinders must be rated at 400 psi or

higher (DOT4BA400 or BW 400).

ªCharge systems with liquid refrigerant to avoid

fractionation.

4

ªManifold sets should be at 750 psi (high side)

and 200 psi (low side), with a 500-psi low-side

retard.

ªUse hoses with a 750-psi service pressure rating.

ªLeak detectors should be of the HFC type.

ªR-410A is compatible with POE oils. POE oils

absorb moisture rapidly. Do not expose the oil to

the atmosphere. Keep all components sealed

until the time of installation/brazing.

ªAliquid-line filter-drier is required on all units, or

per the manufacturer’s directions. Do not use

liquid-line filter-driers with working pressures

rated at less than 600 psi.

ªDo not use an R-22 TXV valve.

ªBraze joints (do not use soft/low-temperature

solder).

Note: Apressure-temperature chart for R-410A is

included on page 6.

5

Technical sources:

DuPont SuvaTechnical Information Bulletin H-65905-2

Carrier Installation and Start-Up Instructions for the 38YXA Heat Pump (023-813)

6

psig °F psig °F psig °F psig °F psig °F psig °F

12 –37.7 114 37.8 216 74.3 318 100.2 420 120.7 522 137.6

14 –34.7 116 38.7 218 74.9 320 100.7 422 121.0 524 137.9

16 –32.0 118 39.5 220 75.5 322 101.1 424 121.4 526 138.3

18 –29.4 120 40.5 222 76.1 324 101.6 426 121.7 528 138.6

20 –36.9 122 41.3 224 76.7 326 102.0 428 122.1 530 138.9

22 –24.5 124 42.2 226 77.2 328 102.4 430 122.5 532 139.2

24 –22.2 126 43.0 228 77.8 330 102.9 432 122.8 534 139.5

26 –20.0 128 43.8 230 78.4 332 103.3 434 123.2 536 139.8

28 –17.9 130 44.7 232 78.9 334 103.7 436 123.5 538 140.1

30 –15.8 132 45.5 234 79.5 336 104.2 438 123.9 540 140.4

32 –13.8 134 46.3 236 80.0 338 104.6 440 124.2 544 141.0

34 –11.9 136 47.1 238 80.6 340 105.1 442 124.6 548 141.6

36 –10.1 138 47.9 240 81.1 342 105.4 444 124.9 552 142.1

38 –8.3 140 48.7 242 81.6 344 105.8 446 125.3 556 142.7

40 –6.5 142 49.5 244 82.2 346 106.3 448 125.6 560 143.3

42 –4.5 144 50.3 246 82.7 348 106.6 450 126.0 564 143.9

44 –3.2 146 51.1 248 83.3 350 107.1 452 126.3 568 144.5

46 –1.6 148 51.8 250 83.8 352 107.5 454 126.6 572 145.0

48 0.0 150 52.5 252 84.3 354 107.9 456 127.0 576 145.6

50 1.5 152 53.3 254 84.8 356 108.3 458 127.3 580 146.2

52 3.0 154 54.0 256 85.4 358 108.8 460 127.7 584 146.7

54 4.5 156 54.8 258 85.9 360 109.2 462 128.0 588 147.3

56 5.9 158 55.5 260 86.4 362 109.6 464 128.3 592 147.9

58 7.3 160 56.2 262 86.9 364 110.0 466 128.7 596 148.4

60 8.6 162 57.0 264 87.4 366 110.4 468 129.0 600 149.0

62 10.0 164 57.7 266 87.9 368 110.8 470 129.3 604 149.5

64 11.3 166 58.4 268 88.4 370 111.2 472 129.7 608 150.1

66 12.6 168 59.0 270 88.9 372 111.6 474 130.0 612 150.6

68 13.8 170 59.8 272 89.4 374 112.0 476 130.3 616 151.2

70 15.1 172 60.5 274 89.9 376 112.4 478 130.7 620 151.7

72 16.3 174 61.1 276 90.4 378 112.6 480 131.0 624 152.3

74 17.5 176 61.8 278 90.9 380 113.1 482 131.3 628 152.8

76 18.7 178 62.5 280 91.4 382 113.5 484 131.6 632 153.4

78 19.8 180 63.1 282 91.9 384 113.9 486 132.0 636 153.9

80 21.0 182 63.8 284 92.4 386 114.3 488 132.3 640 154.5

82 22.1 184 64.5 286 92.8 388 114.7 490 132.6 644 155.0

84 23.2 186 65.1 288 93.3 390 115.0 492 132.9 648 155.5

86 24.3 188 65.8 290 93.8 392 115.5 494 133.3 652 156.1

88 25.4 190 66.4 292 94.3 394 115.8 496 133.6 656 156.6

90 26.4 192 67.0 294 94.8 396 116.2 498 133.9 660 157.1

92 27.4 194 67.7 296 95.2 398 116.6 500 134.0 664 157.7

94 28.5 196 68.3 298 95.7 400 117.0 502 134.5 668 158.2

96 29.5 198 68.9 300 96.2 402 117.3 504 134.8 672 158.7

98 30.5 200 69.5 302 96.6 404 117.7 506 135.2 676 159.2

100 31.2 202 70.1 304 97.1 406 118.1 508 135.5 680 159.8

102 32.2 204 70.7 306 97.5 408 118.5 510 135.8 684 160.3

104 33.2 206 71.4 308 98.0 410 118.8 512 136.1 688 160.8

106 34.1 208 72.0 310 98.4 412 119.2 514 136.4 692 161.3

108 35.1 210 72.6 312 98.9 414 119.6 516 136.7 696 161.8

110 35.5 212 73.2 314 99.3 416 119.9 518 137.0

112 36.9 214 73.8 316 99.7 418 120.3 520 137.3

Table 1. Pressure-temperature chart for R-410A

ALLIED SIGNAL

Refrigeration Service Engineers Society

1666 Rand Road Des Plaines, IL 60016 847-297-6464