refrigeration engineer

[shakey jake]

hi guys
just sorting out a larder. the chiller unit i have been given has four cables, one has a pressure switch the others are all three core.
any body understand these things?
its a riva cold.
the mate i got it from has passed away so im a bit stuck
any advice more than welcome
jake

 

[VSS]

@sikadog is the man you need.