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just been to my dads pub as he has a walk in fridge in the cellar that was not working. After diagnosing it has having no gas i then leak checked the unit and repaired the leak but found it to be running on r12. should i chrge unit with r134a and will i have to change the expansion valve as it is a danfoss tx2 r12. not up on these fridges as i normally work on trasport stuff. your help would be much appreciated cheers eddie
You can get R409a as a drop in replacement for R12 with no changes. A long term soloution would be R134a but yes you would have to change the TEV and also change the oil and flush the system. Hope this helps
you could try r413a, make sure you change the drier. hope this helps, make sure you vac out before charging
I tend to use R413A as well, or sometimes called isceon 49.
works good as a drop in, might have to adjust the superheat a bit, generally charge 10% less than recommended charge and expect flashing in the sight glass.
best choice is the long term retrofit with r134a and poe oil but this takes time and about 3-4 oil changes to get less than 5% mineral oil in the mix also have to change expantion device and dryer
I have converted many systems from r-12 to 134a, as mentioned above you must change the oil to POE, and change the oil at least 4 to 5 times to get the mineral oil down below the 5 % mark, a refractometer is good for this, it will tell you when your safe , change your driers, POE will break loose particles in the system, as far as your TXV, leave it alone, the same txv will work with the 134a , do check your txv for a removable inlet screen, if so, clean it after system runs a few days, set your super heat