HVAC, chiller compressor

[PBeau]

Hello! Everyone.
I am looking for information concerning our chiller compressor. To make a long story short, I am on a friend's sailboat trying to put it back together. I have a unit, AQUAAIR wich has been modified, I don't know how many time.
I would like to know if there is a schematic who would show me the original control. There is two cables 4 cores of maybe #24 AWG going in the back which i can't see. I presume that should ties up to pressure and what else. Also there is a stage control hook to that also, is this compressor multi-stage? How it work.

I wish i had more information.

If someone knows what i am talking about, Please.

PBeau