Greetings to all
I retrofitted a unit cascaded to the second stage with a final temperature of -90 ° C. the system had a load of 1 kg with 0.1 kg R503 R12.
I replaced the oil with oil poe, and primed, 1 kg 0.1kg R23 with R134a.
after the test run the final temperature reaches -65 ° C.
can someone help me with similar experiences?
which you think may be the right mixture of refrigerant retrofit?
Thank you.