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
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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
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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
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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.
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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)
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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
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Refrigeration Service Engineers Society
1666 Rand Road Des Plaines, IL 60016 847-297-6464