There was some time ago a thread about oil separators on packs which I can't find back with the search engine.
There seems to be problems with packs, working of R404a at low condensing pressure where the separator can't separate the oil.
It's just like if you lower too much the discharge gas temperatures,that the separator isn't working properly anymore.
A colleague of my had enormous troubles with it. As soon they increased HP, problem was gone. And as soon the decreased it again, problem came back.
Ever heard of it?
What is the technical explanation for this?
What can be done to solve the problem so that can be worked with low high pressures without the oil problems?