l2embo,

I'd like to see a picture of the surge drum and the pipe arrangement around the surge drum.
Oil will form an oil rich layer on top of liquid R22, so I would like to see the oil drain arrangement as well

-The discharge temperature seems a bit high for that load on the compressor, what is the ambient temperature?

but there is a doubt that oil could possibly migrate into 3 meter vertical suction line and to the surge drum because of the pressure difference.
I agree with this

Looking forward to more pictures