R22 direct replacement

[tinman59]

what refrigerant wiil be a dropin replacement for r 22 and what kind of modifacaitions to the syst will have to be made if any some say 134a i dont think so ?

[wambat]

For refrigeration 417a and for air conditioning 422a

[charlie]

Basically two options:

a) Official one

Most of compressors manufacturers are allowing to retrofit R407c to the R22 systems. Obviously you need to repalce the exsisting mineral oil with ester oil (extremely expensive).

Pros:

- Authorised by compressors manufacturers and normally well documented.
- No need to replace refigerant circuit components (just to adjust TEV)

Cons:

- Lower cooling capacity.
- Higher condensing pressure (HP cut out risk if you are working over 33 - 35 °C ambient temperature).
- If you are leaving a too high amount of mineral oil inside the system (over 3%) you'll develop acidity very quickly.
- Oil return quite unpredictable.

b) Unofficial one.

Du Pont is suggesting the use of ISCEON (there are various type of this blend identified with a number like 29, 59, 79...) that doesn't require the oil replacement.

Pros:

- More economic and fast

Cons:

- ISCEON refrigerants were never approved officially by compressors manufacturers, so if something is going wrong after replacement will be your own responsability and the aen user can blame you because you are using something not "approved".

My personal opinion is that R407c is a s*+#t refrigerant but if the unit is working in a country with a reasonably low ambient temperature during summer period (like UK) probably you have good chances to have a unit working in a decent way for the next 4-5 years.

ISCEON refrigerant is something you have to test by yourself (I'm not tusting very much the "case studies" you can find on Du Pont web site).

[tinman59]

thanks for the info .. i have to many units to replace so il be waiting on the manufactures to come up with a ideal direct repl ***** the climate down here is norm 80% humidity and average temp on a good day is about 87 thanks for your help

[kezzy chiller]

Isceon R59L is a straight drop in and is miscible with the mineral oil in the system, however the working pressure may be a little high so you will probably only need to charge about 70% of whatever amount of R22 you took out.
If you want to retro fit to R407C then you will need to replace the compressor with a scroll type with ester oil, but you will need to flush out the system to get rid of any mineral oil and I mean all of it.
R407C is a harsher substance and works at a slightly higher pressure so a change of expansion device may be needed or high pressure cut out will occur and any mineral oil will wax up and clog the system.
The stability of the indoor coil may come into question also when the unit is in the off mode and the gas equalises out, remember the the pressure will be higher so can the coil cope with it.