Quote Originally Posted by trevor389 View Post
Sedgy yeah the fridge was running but the comp kept cutting out on LP. the suction was going to 8 bar then dropping to below 1 then the comp would cut out. I really would like to understand how theses pressures tell me whats going on but strugleing to understand really. Really appretiate the help guys think ill be on this site quite alot from now lol.
When you get a situation like this, it may not necessarily mean it is short of gas. If you had a blockage somewhere in the system ( a blocked drier for example) then you would get the same thing with the suction pressure dropping low (eventually in to a vacuum if there was no LP switch). If the pressure rises fairly quickly when the compressor switches off then it probably is gas, if it takes a while for the pressures to rises back up again then it is more likely a blockage.

Basically what im trying to say is low pressure doesn´t equal low gas. There are many things that could cause low pressure and you need to learn how to identify them and rule out other possibilities before adding gas. Topping up a system should be the last step to take after everything else is ruled out. Of course there are exceptions to this rule.