Hey guys

I've been working on a 600kw portable trane chiller. Just want some advice on how to top up the oil in one of the compressors. The Fridgy before me put in 12litres of oil then proceeded to add gas into it. Now the compressor won't start as its got a low oil level fault. Now I still need to add around 35kgs of refrigerant but I can't get te compressor to start cause of this oil fault. What's the best way to add oil without evacuating the refrigerant out of compressor. It was a port near the oil filter for filling

Cheers daniel