Freon™ MO99
Refrigerant (R-438A)

Frequently Asked Questions
Product Performance
Is Freon™ MO99 flammable, due to the hydrocarbons in
the blend composition?
No. Freon™ MO99 has an A1 refrigerant safetyclassification designating nonflammability and low toxicity
under ASHRAE Standard 34. Freon™ MO99 has been
proven to be a safe and reliable replacement for R-22 inexisting equipment in the U.S. and around the world.
What is the difference in energy efficiency between R-22and Freon™ MO99?
Energy efficiencies for R-22 and Freon™ MO99 are very
similar over a range of conditions. More details can befound in the Freon™ MO99 product information bulletin.
What is the difference in capacity between R-22 andFreon™ MO99?
Capacity differences between R-22 and Freon™ MO99 willvary according to application. Typical capacity variation is5-10% below R-22. Freon™ MO99 has been in use in
hundreds of thousands of successful retrofits with little to no
impact on equipment performance or increased energy usage.
Most of the R-22 replacement refrigerants have lower
capacity than R-22. Of all of the mineral oil compatible
products, Freon™ MO99 has the closest performance match.
What is the temperature glide of Freon™ MO99?
Freon™ MO99 has a temperature glide of 7–8 °F. This issimilar to other R-22 replacement refrigerants. Because allzeotropic refrigerant blends have glide, the liquid and vapor
have slightly different compositions. As a result, whencharging a system, Freon™ MO99 should be removed fromthe cylinder as a liquid.

Where can I find the pressure/temperature (P/T) chart
for Freon™ MO99?
The Freon™ MO99 P/T chart and additional technicalinformation is available at freon.com. In addition, there is afree mobile “PT Calculator” app for Apple® and Android®
devices that contains P/T conversions and basic productinformation, as well as allows for easy calculation ofsubcooling and superheat.
Why does the P/T chart for Freon™ MO99 have twocolumns of data?
For any zeotropic blend, there is a saturated liquid
temperature (bubble point) and a saturated vapor
temperature (dew point). When calculating superheats,
always use the saturated vapor temperature (dew point).
When calculating subcooling, always use the saturated
liquid temperature (bubble point).
Can a system running on Freon™ MO99 be topped off withmore Freon™ MO99 if it leaks?
Yes. Systems running with Freon™ MO99 can be topped off
repeatedly with Freon™ MO99, with no change in flammability
rating or noticeable performance change. However, as when
maintaining and servicing any system, refrigerant leaks should
be located and repaired as soon as possible.

Product Applications
Can you use Freon™ MO99 in a dry charge system?
Given the similarities between Freon™ MO99 and R-22,
field charging a dry shipped unit with Freon™ MO99 is agood option for eliminating ozone depleting substancesand managing the transition from R-22. OEM warranties
should be considered when looking at dry ship possibilities.
Even with the newer POE-based dry charge units, Freon™
MO99 is a good option, because it is fully compatible withpolyol ether (POE) lubricant as well.

Freon™ MO99

Refrigerant

Can Freon™ MO99 be used in systems with capillary

SNAP listed as an approved R-22 alternative by the U.S.

tubes sized for R-22?

EPA, nor is it produced to the specifications of Freon™

Yes. The mass flow rate and operating pressures of Freon™

MO99. The name of BMP438 is believed to be used toMO99 are the closest of all the mineral oil compatible
replacement products and will likely perform adequately inan existing R-22 system with a capillary tube expansion
device. However, for optimal results, it is recommended toreplace the capillary tube with a TXV when possible.

confuse contractors and end users looking to purchaseFreon™ MO99, which has an ASHRAE designation ofR-438A and is SNAP listed.
How much does Freon™ MO99 cost?
Please consult a Chemours authorized distributor forDoes Freon™ MO99 work in heat pumps?

specific pricing. Because Freon™ MO99 is an HFC blend,Yes. Freon™ MO99 can be used to retrofit R-22 heat pumps .

and therefore not subject to phaseout like R-22, it isBased on system testing, similar efficiency and slightly lower
capacity can be expected. A slightly lower capacity may force
the compressor run time to increase. When in the heat pumpmode of operation, many systems use a capillary tube or fixedorifice as an expansion device, so the charge size of Freon™
MO99 will need to be optimized to obtain the proper amountof subcool/superheat. Follow retrofit guidelines available atFreon.com to ensure the system is not over- or under-charged.

reasonable to expect Freon™ MO99 to be priced lower than
R-22 and comparable to other R-22 replacement
refrigerants. As a result, Freon™ MO99 provides a quick,low cost retrofit solution that also helps end users delay
investment in new equipment.
Are there supply restrictions or constraints on Freon™
MO99?
No. Freon™ MO99 is readily available nationwide for purchase

Can Freon™ MO99 be used in flooded evaporators?

through Chemours distributors. Please visit Freon.com andLike any zeotropic refrigerant blend, Freon™ MO99 is not

click on the “where to buy” button for a distributor near you.

recommended for use in flooded evaporators. We advise
contacting the original equipment manufacturer (OEM) for
guidance on conversions from R-22 in a flooded system.

Is there a phaseout plan for Freon™ MO99 in air
conditioning applications?
As of October 2016, there are no current or pending

Can Freon™ MO99 be used in low and medium

regulations to phase out Freon™ MO99 in air conditioning

temperature refrigeration applications, in addition to airapplications in the United States. For other countries,conditioning or heat pumps?

please consult your local Chemours authorized distributor

Yes. Freon™ MO99 works well in low and medium temperatureor representative.

refrigeration, as well as air conditioning or heat pumps.

Product Availability and Cost

Retrofit Information
Does Chemours have retrofit guidelines for converting

I used to use a product called ISCEON MO99™. Is it theR-22 systems?

same as Freon™ MO99?

Yes. An “8 easy step” booklet, detailed retrofit guidelines,

Yes. When DuPont spun off its Performance Chemicals

and a brief R-22 retrofit video are available at Freon.com®

business unit in July 2015 into a separate company called
Chemours, the decision was made to simplify the number ofrefrigerant brand names used to identify our products. As aresult, all HCFC and HFC products have been re-brandedwith the Freon™ brand, but continue to be produced in thesame quality manufacturing facilities that the industry has

under “8 Basic Steps to Retrofit from R-22”.
How many pounds of Freon™ MO99 need to be added
during a retrofit compared to R-22?
For most retrofits, the charge size required for Freon™
MO99 should be comparable to the charge size needed

come to expect from the Freon™ brand under DuPont.

with R-22. However, there could be some slight variations

I have heard of a product called “BMP438”. Is it the same

When charging an R-22 system with any replacement

as Freon™ MO99 (R-438A)?

refrigerant, it is recommended to always start with

No. BMP438 is a product manufactured and imported fromapproximately 10% lower charge of the new product,

China that does not have an ASHRAE designation, nor is itdepending on system design and type of expansion device.

check the system superheat or subcool, and then add theremaining refrigerant until the system is running as desired.

Freon™ MO99

Refrigerant

Can R-22 be topped off with Freon™ MO99?

What oils work with Freon™ MO99?

No. Freon™ MO99 should not be used to top off R-22

Freon™ MO99 is compatible with both traditional andsystems. Mixing refrigerants is not recommended. R-22

synthetic lubricants: mineral oil, alkyl-benzene (AB), and polyol

should be recovered using appropriate equipment andester (POE).

managed according to U.S. EPA guidelines specified inSection 608 of the U.S. Clean Air Act.

Can POE oil be introduced to the existing mineral oil andDoes Chemours have a reclaim program for R-22?

POE and mineral oil can be safely mixed in any proportion

In the United States, Chemours does offer an R-22 reclaim

and used with Freon™ MO99. In many R-22 systems, theprogram. The recovered R-22 is a valuable asset, for use inconversion to Freon™ MO99 can be made with no change

servicing other equipment or by reclaiming back through anor addition of POE to the existing mineral oil. In cases withauthorized dealer. More information is available on thedifficult oil return, such as systems with a liquid receiver

Chemours website under “U.S. Refrigerant Recovery &and no oil separator, or complex line sets, a small amount

Reclaim Program” at Freon.com. For other countries, please(~20%) of POE added to the system can aid oil return. For

contact your local Chemours authorized distributor orTrane® 3-D® and Danfoss SM scroll compressors, a single

representative regarding reclaim options.

oil change in the compressor oil sump from mineral oil to an

What happens if R-22 gets mixed into an installation ofFreon™ MO99 that is not properly labeled?

mixed safely?

OEM-approved POE lubricant is recommended. Multiple
flushes of POE to remove all of the mineral oil are notrequired with Freon™ MO99. Consult detailed retrofit

Mixing refrigerants is never recommended. However, based

guidelines for additional details on system oil managementon the similar operating conditions of Freon™ MO99 andand specific equipment, where a single or full oil change

R-22, system damange would not be expected. At the nextwould be recommended. Note that this oil management

available service opportunity, it would be advisable toguidance is not specific to Freon™ MO99 and would berecover and dispose of the mixed gas, and charge and label

necessary when using any “no oil change” HFC blend withthe system with either R-22 or Freon™ MO99.

these compressors or system configurations.

What seals need to be changed when converting fromWill using Freon™ MO99 void my equipment warranty?

R-22 to Freon™ MO99?

Freon™ MO99 has more OEM approvals than any otherR-22 penetrates elastomeric seals more substantially thanmineral oil compatible R-22 retrofit refrigerant. However,any HFC refrigerant, such as Freon™ MO99. When R-22 is

not all OEMs approve R-22 retrofit refrigerants. For

removed from a system, it off-gases and the elastomericwarranty questions, it is always recommended that theseals shrink and are not likely to return back to that size

appropriate OEM be contacted. It is important to note thatafter charging the system with an HFC blend, leaving anin many cases, where retrofit refrigerants are used to delay

opportunity for a leak. As part of a good R-22 retrofit

future investment in new equipment, the warranty of theprocedure, critical elastomeric seals (seals that cannot be

R-22 equipment undergoing a retrofit has already expired.

isolated when the system is operating) should be changed
with ones that have not been used in R-22 service

Product Comparison

previously. Typically, the Schrader core and pin on the service

How does Freon™ MO99 performance compare tovalve should be replaced with a new one that has not been in

R-407C in air conditioning applications?

R-22 service. For larger, more complex systems, there may

Freon™ MO99 and R-407C both match the performance

be other elastomeric seals present. A brief training video canbe found on Freon.com that addresses this topic.
When retrofitting or servicing an Freon™ MO99 system,
can you use the same gauges as used with R-22?
Yes. Freon™ MO99 and R-22 have very similar pressure
characteristics, and, therefore, the same gauge sets canbe used.

(energy efficiency and capacity) of R-22 well and are good
replacements for many air conditioning applications. The
main difference is that pure HFC fluids, like R-407C,
require a complete change out of mineral oil to POE
lubricant for R-22/MO systems; whereas; Freon™ MO99
was specifically formulated to be used without the need foran oil change out, which saves time and money.

Freon™ MO99

Refrigerant

Why is a complete change out from mineral oil to POE

were maintained, oil coating and fouling of heat exchanger

lubricant required for R-407C, but not Freon™ MO99?

surfaces can lead to significantly degraded heat transfer

Freon™ MO99 is a specially formulated nonflammableand inadequate system capacity and poor energyblend that contains small amounts of hydrocarbons. The
low levels of hydrocarbon have a high solubility in mineraloil, lowering viscosity and enabling efficient oil return fromcold evaporators. R-407C does not have this capability
and, therefore, requires change to a fully miscible oil, suchas POE, to ensure adequate oil return from the evaporator

efficiency. For these reasons, most major compressor
manufacturers require removing >99% of the mineral oil
when converting to R-407C.
There are other “no oil change” products advertised; whyis Freon™ MO99 the best?

and piping to the compressor.

While other products have been introduced with small

What could happen if an oil change to POE was not done

Freon™ MO99 (R-438A) is the best overall all performance

when using R-407C?

match (energy efficiency, capacity, operating pressures, andIf R-407C is used without a full oil change to POE, there ismass flow rates) to R-22 in air conditioning applications.

amounts of hydrocarbons to help with mineral oil compatibility,

a possibility of inadequate oil return from the system backto the compressor, which could lead to lack of mechanical

The table below summarizes the performance of Freon™
MO99 versus other replacements relative to R-22.

lubrication, overheating, and potentially compressor failure.
Additionally, even if adequate oil levels in the compressor

R-438A

R-422DR-422B

R-421A*R-424A

R-32/125/134a/600/601a
8.5/45/44.2/1.7/0.6

R-125/134a/600a
65.1/31.5/3.4

R-125/134a/600a
55/42/3

R-125/134a
58/42

R-125/134a/600a/600/601a
50.5/47/0.9/1.0/0.6

Brand Name

Freon™ MO99Genetron® 422DFreon™ MO29

NU-22B®

Choice™

RS-44Cool50

Capacity (%)-7-8-12-12-15

COP (%)-2-4-3-5-1Suction Pressure (psi)-3+1-6-7-11Discharge Pressure (psi)+5+12-5-7-17Discharge Temperature (°F)-30-39-37-36-38

Blend

Temperature Glide (°F)

+7+5+6+6+5.5

Mass Flow (%)+12+32+20+21+12Performance relative to R-22; (+) is increase, (-) is decrease
Calorimeter Data at AHRI Standard 540 air conditioning conditions
45 °F Average Evaporator Temp/115 °F Average Condenser Temp/65 °F Return Gas Temp/15 °F Subcool from Average Condenser Temp
*POE Oil Change typically recommended for “HFC Only” Blends

For more information on Freon™ refrigerants, visit freon.com
The information set forth herein is furnished free of charge and based on technical data that Chemours believes to be reliable. It is intended for use by persons having technical skill, at their own risk. Because
conditions of use are outside our control, Chemours makes no warranties, expressed or implied, and assumes no liability in connection with any use of this information. Nothing herein is to be taken as a license tooperate under, or a recommendation to infringe, any patents or patent applications.
© 2016 The Chemours Company FC, LLC. Freon™ and any associated logos are trademarks or copyrights of The Chemours Company FC, LLC. Chemours™ and the Chemours Logo are trademarks of The Chemours Company.
Genetron is a registered trademark of Honeywell; NU-22B is a registered trademark of Icor International; Choice is a registered trademark of RMS of Georgia.
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