Replacement For R502

Hello All, again the lack of spares and support in Zimbabwe & Botswana is causing major problems. I have a number of older Minus 40 chest freezers (Domestic) to repair, by the way Minus 40 is a brand name. Almost all these units are using R502. I know that the replacement refrigerant for R502 is R404a, which is obtainable in my area. The problem is that the cost of converting the older units to R404a is very heavy. As a result, it makes sense for my customes to simply buy new freezers as apposed to repairing the old ones. This results in my losing business and is rather a shame as these freezers, are generaly in good condition. Is there a "drop in" refrigerant available? If not, can someone suggest a workable alternative.

Many thanks

Mastercool

Dupont HP80 (R402A)
forane FX10 (R408A)
I used a few drop ins for R12, R500 and R502 back in the mid 1990s, don;t know if they are still available or they ended up being any good though :)

Hello Paul, many thanks for the quick reply. Are you sayimg that i can use R408a to top up a R502 system? If so I am very glad as a canister of R408a is in fact available.

Says not to mix it with r502 or use it for top ups here:
http://www.arkema-inc.com/index.cfm?pag=35
assuming you meant 'top up' as adding to a r502 system. But if you meant evac and charging just with 408A, yes you can.

Hello again, many thanks for your help. I have looked the data on R408a and am sure that the use of that refrigerasnt is in fact the answer to my problem.

Thank you again

R403b (69L) is also a direct drop-in for R502. It has better capacity at lower temperatures.

R408a eventually discolours the oil if working in high ambient temperatures. Might consider drier change as well.

r408a is a drop in for 502 however it contains around 70% r22 so if the phase out affects you then it is a bad choice

Many many thanks for all the comments. I am able to obtain R408a in Botswana. This will make my life so much easier.