R12 to R22 or R409

I need your help. I am currently working on a laboratory water chiller. The mfr is telling me that the system I am working on is an R12, 220Gram charge. This moring they said R134A or R409A would be fine to use. This afternoon they call back and leave a message that I need to use R22, 160 grams. It is a cap tube system. Original comp is danfoss PW 3.5K7. It is DX with the water and minimum temp is -20C.

I have never heard of switching out R12 with R22. What is your opinion? Wouldnt R409A be better? I am leaning to the R409a.

It is for the water baths we have been discussing in the fundamentals section.

Thank you for the help in advance

I think going to R22 will cause problems.
The suction pressure will rise, along with the head. Unless the motor on your compressor has a lot of capacity left you are liable to over amp.
I once did this by accident, and discovered my error immediately, when the Klixon started to cycle.

As I recall The MG Pony was going to experiment with this a short while ago. Perhaps if he has done this he will share his results.

Use sp34e or isceon 49 for r12 drop in replacements.
r22 = higher pressures, a capillary system isn't going to work right.
Isn't r409 based on chloro fluoro carbons, ie r22 etc, that will be banned in most places soon.
sp34e = r134a and propane, safe for a long time.

For replacement of R 12, the most suitable is R 134a. The minimum temperature you require is - 20oC. R 134a will maintain this conditions.

The comp has mineral oil. Is R134a plus R290 still ok?

also i have the same problem here back home...before we use r 12 but now we don't find anymore this kind of refrigerant...i spoke with our guys here and some of them told me to use r134a but to change the oil...i can't change the oil of each compressor cause our costumer don't won't to pay for it...so tell me which is the best solution for replace r 12 and to work with the mineral oil..r134a or r409a?those are the only choice here in my city..can i have a sugestion????
thks

Hi Ultralo1
I'd use R413A (isceon 49) as it has similar running pressures to R12 and is designed to run with mineral oil. You will need to weigh in less than with R12 as pint fo pint it is lighter (10% ish) so about 90% by weight. will need trial and error in a critical charge/capiliary system.

Hi tarcau mihai
Out of your two choices i'd use R409A as it will work with mineral oil. But it has R22 as part of the blend and will be unavailable when R22 production stops (2010) So if available i'd use R413A (isceonR49) again both these blends will need less weight charged than R12 about 90%

Jon

I agree with the Monkey Spanners above. We use isceon 49 very sucessfully for all R12 replacement, it is also a HFC so is not due for phase out.



Col

I would use R49 as it is a drop in for R12 and would not need an oil change

Peter

Thanks guys. All of the suggestions are greatly appreciated. I hate it when the mfr engineers give conflicting info. Even when you talk to them they dont want to listen. It seems that they were just reciting out of a book instead of thinking. A

Again thanks guys

I'd go with the R-49 blend and be done with it. You can not charge vapor though, it has to be liquid charged.

Ken

Quote:

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Originally Posted by ultralo1

The comp has mineral oil. Is R134a plus R290 still ok?

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R-134a 80%/R-600a 20% Will mimic R-12 satisfactorily.

Oh and NHL3R That was R-22 & 502, I was going to try that R-134a/R-600a mix, need to get some more cylinders and such ready befor I can mix it though!