Arkema’s Forane® 427A

For more than 15 years, Arkema has offered its proprietary blend, Forane® 427A (R-427A) – The Easy Retrofit™, as an alternative to R-22 in air conditioning or refrigeration applications. The main advantage of R-427A is that in most systems, it can be used with the existing mineral oil or POE oil, whereas other refrigerants must be used with POE oil, said John Maiorana, product support manager of Forane refrigerants at Arkema Inc. (North America).

“Forane 427A is one of the most popular R-22 retrofits,” he said. “It has a GWP of 2024 and offers an approximately 3 percent capacity loss compared to R-22. It has the closest performance to R-22 in terms of capacity and efficiency when compared to other retrofits in the market. Of course, how the system is currently running on R-22 will always affect final performance.”

PROPRIETARY BLEND: For more than 15 years, Arkema has offered its proprietary blend, Forane 427A – The Easy Retrofit, as an alternative to R-22 in air conditioning or refrigeration applications.

R-427A can be used in both refrigeration and air conditioning applications, and while it will work in low-temperature applications, alternatives like R-407A will generally work better, said Maiorana. The trade-off is that the oil will need to be changed.

“The warranties on many R-22 systems have expired, and most replacement R-22 compressors are now coming charged with POE oil,” he said. “Therefore, compressor manufacturers have adopted R-407C with POE as a recommended refrigerant. Forane 427A and R-407C are very close in composition, with R-427A having the addition of R-143a for enhanced oil compatibility. Therefore, Forane 427A offers the flexibility to work in compressors containing POE or mineral oil.”

With any alternative refrigerant, it is important to understand that it should not be used to “top off” a system that uses R-22 (or any other refrigerant). Technicians should always first recover (and reclaim) the R-22 before introducing any new alternative to the system. As Maiorana noted, there are inherent risks when mixing refrigerants, because their pressures and temperatures are different; in addition, the alternative will contaminate the existing R-22, making it more difficult to reclaim.

To make sure the retrofit goes smoothly, Maiorana recommends the following steps when changing an R-22 system to R-427A:

1. Record how the system is running on R-22, then recover the R-22 charge and replace the filter drier;
2. Check the oil for contamination and determine whether the system layout warrants adding or changing over to POE oil (e.g., elevation changes back to compressor, long line sets, receivers, etc.);
3. Replace the external seals/gaskets (Schrader cores), check for leaks, and weigh in liquid refrigerant to 90 percent of the original R-22 charge; and
4. Run the system and add the retrofit refrigerant as needed to get the desired superheat and subcooling (normally, when using R-427A, no TXV adjustment is required).

Before offering a refrigerant retrofit, a technician should always take into account the current performance of the unit, its age, and the end user’s best interest, said Maiorana. Price and availability of R-22 are also important factors.

“There is no need for a one-size-fits-all approach,” he said. “In some cases, just topping off a current R-22 unit with additional R-22 is the right choice. However, if the unit is still functioning well and has service life left, technicians might consider that a refrigerant retrofit is the less costly choice for the end user.”

Choice’s R-421A/R-421B

Ken Ponder, owner of Choice Refrigerants, invented R-421A and R-421B in 1995, once it became apparent that CFCs and HCFCs would be phased out. He said these replacement refrigerants can be used in most types of equipment with very little — if any — difference in capacity or efficiency when compared to R-22.

“The age of the equipment is also not a factor, since these alternatives were designed to run in older equipment,” he said. “In fact, alternatives were designed to help extend the life of a unit, especially if the original refrigerant was phased out and the cost has gone up. Unfortunately, too many technicians use the excuse of a leak or the age of the equipment to simply recommend that the customer buy a new unit.”

If the decision is made to retrofit an R-22 system with R-421A or B, Ponder said these steps should be followed:

1. Collect operating data from the pre-converted system and record for post-converted reference;
2. Recover the existing refrigerant and record the amount recovered, as this will help determine the amount of R-421A the system needs;
3. Determine oil composition, including moisture content and acidity, and also check for particulate matter such as metal shavings or rust. If the system’s oil does not meet desired specification, perform a complete oil change prior to converting the refrigerant;
4. Install a new oil filter and filter drier. If the system contains a compressor oil filter or coalescent oil separator, replace as needed;
5. Check for leaks. Check the unit’s designed pressure level, and conduct a pressure test using dry nitrogen to determine if the system contains a leak;
6. Evacuate the system. In order to remove all non-condensables and moisture from the system, a minimum vacuum of 500 microns is required;
7. Charge the system with Choice R-421A in a liquid state only to the high-pressure side of the system. The correct charge will vary for each system, though it is recommended that the initial charge be 90 to 95 percent of the original R-22 charge. The final weight of the charge will be determined by superheat or subcooling;
8. Start the system and evaluate system performance by checking the subcooling, superheat temperatures, and pressures (reference the Choice PT chart as needed). R-421A can be topped off multiple times, or until desired performance is reached; and
9. Properly label the converted system, perform leak tests as needed, and record the system’s performance and compare to pre-conversion evaluation.

“In choosing an alternative refrigerant for the masses, it’s hard to beat our R-421A,” said Ponder. “It has the closest pressure temperature product compared to R-22, and it’s also the only two-component blend in the market, which helps in the glide being the best over the operating range. R-421A is also the only legal refrigerant that comes packaged with a performance-enhancing lubricant, which helps every system. That’s why we call it the ‘Easy Choice.’”

ComStar’s R-453A And R-434A

ComStar International Inc. has two R-22 alternative refrigerants available. The first, RS-44b (R-453A) is the replacement that can be used for all R-22 non-flooded, high-, medium-, and low-temperature systems down to minus 20°F evaporating temperature. Unlike other R-22 replacements, the addition of POE oil to the system is not required with R-453A, said Steven Mella, CEO of ComStar International Inc.

The second alternative, RS-45 (R-434A), is a replacement for R-22 flooded systems, which are normally found in ice rinks, cold storage facilities, and process cooling systems in chemical plants. R-434A is the only replacement for R-22 flooded systems that does not require changing the oil or expensive components, said Mella.

Some of the advantages of using R-453A as an alternative to R-22, he said, include the following:

• Same flow rate as R-22;
• Similar discharge pressure as R-22;
• Similar energy efficiency as R-22;
• Matches R-22 cooling capacity;
• No oil change required; compatible with mineral, AB, and POE oils;
• No system component changes required;
• Replaces R-22 in both air conditioning and refrigeration equipment down to minus 20°F evaporating temperature; and
• Lowest GWP HFC R-22 replacement on the market at 1636.

“If working on a residential air conditioning system, all technicians need to do is evacuate the R-22, change the filter (if system has one), and put in the R-453A,” said Mella. “With R-453A, it is not necessary to add any POE oil to the system, as the refrigerant incorporates a very small amount of hydrocarbons, which enhance oil return to the compressor.”

For R-434A, the conversion may be as simple as removing the R-22 and adding the new refrigerant, depending on the design of the flooded system, said Mella.

“If the system has oil return issues, then it is recommended to change out the oil to ComStar POE-HMC oil, which was specifically formulated to work with RS-45 in flooded systems with oil return issues,” he said. “Like all HFC blends, when charging either R-453A or R-434A, the refrigerant needs to be in the liquid phase, so the cylinder needs to be turned upside down.”

Surprisingly enough, Mella said that he often receives phone calls from homeowners who say their HVAC contractor has told them that R-22 is no longer available and that they need to buy a whole new system.

“We realize that situation happens, but there are many HVAC contractors who offer an R-22 alternative to their customers if the system is still serviceable and has life left in it,” he said. “Also, believe it or not, we meet service people at shows or counter days who don’t even know that R-22 alternatives exist.”

Given the various types of alternative refrigerants available, contractors and technicians should take the time to learn about each one, so they will be able to offer their customers the best solution for their particular equipment.