My unit has r502 freon. It is a little low and I have been told r502 is hard to find. Does anybody know if you can mix r404 with it by simply adding it in or does the system have to be retrofitted completely? Any help would be greatly appreciated.

According to my friend who is an HVAC guy on a fishing processer it can be done. The only draw back is getting the old refridgerant out and stored w/o leaking. You need an HVAC license for this. Hope this helps.

looks like 600.00 for 30 lbs of refrigerant not counting capture fees.