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Frequently asked questions

We’ve collected a list of frequently asked questions right here.  If you don’t find your specific question listed, let us know! We designed this site with you in mind and want you to be able to access everything you need in one place.

Most retrofits have a higher GWP than R-22. Why should I retrofit?

While it's true that most retrofits have a higher GWP, R-22 is an ozone-depleting substance and, as such, is being phased out. The retrofits are based on non-ozone-depleting HFC technology. Additionally, while certain retrofits have a noticeably higher GWP (i.e. R-507A), products like R-407C, R-407A, and R-427A have GWP values that are comparable to R-22.

If a refrigerant is a blend, do I have to replace all of it after a system has had a leak?

Typically, that is not necessary. Fractionation, or changes in blend composition, can result from leaks. However, the type of leak, system design/usage, and specific refrigerant all affect fractionation. Changes in composition from liquid leaks tend to be small. Leaks on regularly running DX systems produce little fractionation, as refrigerant flow keeps the components mixed. Fractionation from leaks of azeotropic/near-azeotropic blends also tend to be slight. In many cases, once a leak has been repaired, the system charge can simply be topped off.

Is there one retrofit that will work in all R-22 systems?

Unfortunately, there is no retrofit with the versatility of R-22. Forane® 427A does as good a job as any in covering the broadest range and has been successfully used in AC, MT, and LT systems. It has a slightly lower capacity than R-22, so be sure to consider system loading. It's also a high-glide blend and isn't typically recommended for flooded evaporators.

What values should I use for superheat / subcooling when doing a retrofit?

Superheat should be kept at similar levels to what is recommended by the OEM for the original refrigerant. For TXV systems, subcooling must also be monitored to insure that only liquid enters the valve. A subcooling value of at least a few degrees at the condenser outlet should be sufficient for most applications.

Are multiple POE flushes required for R-22 retrofits?

Replacing most of the MO/AB with POE helps ensure reliable oil return. However, this may not always be necessary. Many systems perform well after just one POE oil change. Systems with an oil separator have operated successfully on a partial POE oil change, or in some cases without POE. Best practice, however, is to follow the OEM's recommendations.

Can I top off a system with a retrofit refrigerant?

“Field mixing” of refrigerants is an unacceptable practice. Although many refrigerants on the market today are blends, they are blends that have been carefully designed and tested to give specific performance criteria, while maintaining prescribed levels of safety and compatibility. Mixing refrigerants can create products of questionable performance and safety. Additionally, troubleshooting systems with field-mixed refrigerants can be difficult, as the newly created mixture’s pressure/temperature characteristics are undefined. Lastly, most field-mixed refrigerants can not be reclaimed and must be destroyed. As such, the cost of returning recovered field-mixed refrigerants is significantly higher. Before performing any refrigerant retrofit, recover the entire old refrigerant charge and evacuate the system.

I have two 30 lb. Forane® 134a cylinders with different fittings. Why is this, and are the gases inside different??

R-134a is the only refrigerant approved for use by the automotive OEMs, in both new vehicles and for retrofitting older R-12 automotive A/C systems. To prevent cross-contamination, the automotive industry switched from the standard A/C fitting (1/4” flare) to a new fitting (1/2” ACME thread). As such, two types of Forane® 134a cylinders are on the market: stationary and mobile. Stationary cylinders use the standard flare fittings. Mobile cylinders are intended for automotive A/C and have the ACME fittings. This is an SAE (Society of Automotive Engineers) requirement. Regardless of which fitting is present on the cylinder, the Forane® 134a refrigerant inside is identical.

Do Forane® disposable cylinders have dip tubes??

No. Experience has shown that the dip tubes in disposable cylinders occasionally fall off. This can lead to the accidental charging of blended refrigerants as vapor instead of liquid, which ultimately causes the blend to fractionate and affects performance. And so, there are no dip tubes in Forane® disposable cylinders. To remove liquid refrigerant from these cylinders, turn the container upside down, as indicated on the box and cylinder body.

Can I use a Forane® disposable cylinder as a compressed air cylinder??

Forane® disposable cylinders are just that: disposable. They are intended for one-time use. Reusing disposable cylinders for any reason is not permitted. Additionally, many of these cylinders are not rated to handle the pressures that may be reached if used as a compressed air reservoir. Overpressurizing the cylinder could result in equipment damage and/or serious injury. Finally, because the disposable cylinders are thin-walled metal, the constant cycling of air pressure could cause the metal to fatigue and fail, which again could cause equipment damage and/or serious injury.

Many R-22 retrofits say they work with MO and AB. Aren't these products drop-ins?

No, there are no drop-ins. As no two refrigerants behave alike, there will be performance differences. As for claims of working with MO/AB, this is based, in part, on additives (i.e. hydrocarbons) mixed with HFCs. While additives may improve oil solubility, these blends are still immiscible with MO/AB. As with HFCs, acceptable results may be achieved in some systems. However, other systems will struggle with oil return and logging.

How do I measure the contamination of the POE oil after doing an oil change?

Oil test kits are available at most refrigerant wholesalers and distributors. These kits use a chemical reaction to measure the oil purity level. Refractometers are also available for this task. These electronic devices measure the scattering of light through the different oils to determine their relative concentrations.

Can I add a small amount of hydrocarbon to my system to improve oil return?

Although some refrigerant blends use small amounts of hydrocarbons in an attempt to promote oil return, “field mixing” of refrigerants is an unacceptable practice. Controlling refrigerant flammability is an exacting science, and even a small amount of hydrocarbon can make refrigerant blends flammable. Hydrocarbons reduce oil viscosity. This also reduces the lubricating ability of the oil, which could potentially damage the compressor. Also, a small amount of hydrocarbon in a refrigerant blend does not ensure adequate oil return. Finally, hydrocarbons are highly flammable and as such require that strict safety precautions be in place before being used.

Can I use PAG oil instead of POE?

PAG (polyalkaline glycols) oils are used in automotive A/C applications, and are not typically recommended as substitutes for POE oils. Experience has shown that PAGs, used in systems with semi-hermetic/hermetic compressors, sometimes attack the motor-winding insulation, causing shorting in the compressor. This is not a problem in automotive A/C, as these systems use open drive (belt-driven) compressors that do not expose the motor windings to the refrigerant and oil.

Will POE oil work with CFCs and HCFCs?

Polyolester oils are typically miscible with CFC-, HCFC-, and HFC-based refrigerants, and as such should promote proper oil return with any of these products. There are some known compatibility issues with POEs and elastomer materials used in older systems, so consult your OEM for specific refrigerant oil recommendations.

When retrofitting, can I avoid changing to Alkylbenzene (AB) or Polyolester (POE) by using a lower viscosity mineral oil (MO)?

Reducing oil viscosity to promote oil return, when performing a refrigerant retrofit, is not a recommended practice. Although lowering the oil viscosity might improve its movement throughout the system, it also decreases the oil’s ability to properly lubricate the compressor. This could adversely affect the compressor life. Additionally, lowering the oil viscosity might increase the amount of free oil circulating throughout the system. Even a small increase in the amount of circulating oil can reduce system performance. The best way to ensure proper oil return when performing a retrofit is to use an approved, miscible refrigerant/oil combination. The new oil should have the same viscosity rating as the product it replaces.

I started charging a blend as vapor instead of liquid. Will my system work?

Fractionation of a refrigerant blend (separation of the blend components) can occur by removing the refrigerant from the cylinder as a vapor instead of a liquid. This can potentially lead to both safety and performance issues. As such, Arkema recommends charging all blends in liquid phase only. From a safety standpoint, a blend with an A1 (formerly A1/A1) ASHRAE safety rating (like Forane® 409A) will remain nonflammable, even after fractionation has occurred. Performance may be dramatically affected, depending on the extent of fractionation. If only a small amount of the refrigerant placed into the system was charged as vapor, the blend may perform adequately. The performance of systems containing larger percentages of a blend charged as vapor is more likely to be affected by fractionation. Typically, more of the high-pressure components will be found in the system, and less in the cylinder. Pressure checks on both the cylinder and the system may give an indication as to the extent of the fractionation. Measure the pressures of the cylinder and the system when they have reached a constant, uniform temperature. The system should be shut down, and pressure measurements should be taken at a location where both liquid and vapor are present. If the pressures of both the cylinder and system are close to the value listed on the pressure/temperature chart, the extent of the fractionation effects are likely to be small. Significant pressure differences may indicate a high level of fractionation, which is likely to affect performance. Additionally, the refrigerant remaining in the cylinder may also be compromised. In these cases, we recommend contacting Arkema’s Refrigerant Hotline for technical support. It is also important to note that if the entire contents of a refrigerant-blend container (full cylinder) are charged into a system as vapor, it will produce the same effect as charging the entire cylinder as liquid. Also, certain refrigerant blends (zeotropes) are more susceptible to fractionation than others. For example, fractionation is a greater concern when working with Forane® 409A (a zeotropic blend) than when working with Forane® 410A (a near-azeotropic blend) or Forane® 507A (an azeotrope).

Is R-134a a blend and how do I charge it?

No. R-134a is a single component (pure) refrigerant. To determine if a refrigerant is a blend, refer to the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) designation (R#). Blends have 400 and 500 series R#s (R-410A, R-500, R-507A, R-502, R-404A). Any other ASHRAE designation denotes a single-component refrigerant (R-12, R-22, R-23, R-123). Singlecomponent refrigerants can be charged in either phase, while blended refrigerants must be charged in liquid phase only. It is important to note that not all refrigerants have an ASHRAE designation, and many manufacturers use different numbering systems for their products.

Why do I need to remove the mineral oil when retrofitting from a CFC to an HFC?

Mineral oil is not miscible with HFC refrigerants. As such, it may not be carried back once it has been swept out of the compressor. Once the mineral oil enters the system, it typically migrates to the coldest point in the system. This location is usually the end of the evaporator or just after the expansion device. Over time, this oil may decrease the heat-transfer capability of the evaporator and could clog the expansion device.

When should I use an HFC and when should I use an HCFC?

HFCs should be used when installing new equipment. Most OEMs now manufacture new equipment containing HFCs. HCFCs should be used primarily for retrofitting existing CFC systems. Many HCFCs have good miscibility with mineral oil, and as such can often be used as CFC retrofits without having to change the oil. HCFCs typically make retrofitting much easier, and in some cases may improve system performance.

What is the difference between an azeotrope and a zeotrope?

An azeotrope (500 series) is a refrigerant blend that cannot be separated through distillation at a specific temperature and pressure. These refrigerants do not have a measurable glide, and therefore fractionation is typically not a concern. Examples of azeotrope refrigerants include R-500, R-502, and R-507A. Zeotropes (400 series) are refrigerant blends that have a glide and can fractionate. Examples of zeotropes are Forane® 408A and Forane® 409A. Some zeotropes are referred to as near-azeotropes. These are 400-series refrigerant blends that typically have small or negligible glide and fractionation effects. Forane® 410A is an example of a near-azeotropic refrigerant.

Why do you need to charge blended refrigerants as liquids?

Refrigerant blends are simply a mixture of different refrigerant components. As such, if they are charged as vapor, the refrigerant with the highest vapor pressure will be charged at a higher proportion than the other component(s). Charging as a liquid is the only way to guarantee that the blend is charged within its designed composition.

Why are there so many blends?

When the CFCs were eliminated, many refrigerant manufacturers developed their own replacements to satisfy the needs of the refrigeration and A/C industries. Each one of these blends is different from the others with regards to composition and performance characteristics. End users should educate themselves as to which blends are the safest, easiest, and most cost-efficient refrigerants to use in their retrofits.

If a system charged with a blend leaks, will I have a problem with fractionation?

For Forane® 404A, Forane® 408A, Forane® 410A, and Forane 507A leaks are not an issue. The glide in each of these blends is very small (if any) and therefore, fractionation due to leakage is not a problem. Leaks with high glide blends, like R-409A, may be more of an issue. Top-offs may still be acceptable in many cases. However, additional analysis, such as pressure checks, may be warranted.

Do I have to retrofit my R-22 equipment?

No. There is no retrofit mandate. The need to retrofit systems will be driven by a variety of market factors, including refrigerant availability. If your R-22 equipment is relatively leak-free, your best option may be to simply maintain your equipment.

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