Oil Pressure on a Trane 40 ton

ninjaneer

Hey all, I have a Trane 40 ton reciprocating compressor that is kicking out on the motor pack.  I have checked the oil pressure on it and in first stage it has a pressure delta of about 10 psi, in second stage it has a negative oil pressure of about 5 to 10 psi.  My thought is that it is the oil pump, what are your thoughts??

Eugene_Silberstein

Need about 30 psig net oil pressure

Typically, a system needs a net oil pressure of at least 30 psig to allow the compressor to continue operating. A (90 second or so) timer allows the compressor to operate and provide ample time to build up the necesary oil pressure for continued operation.



Net oil pressure is determined by the oil pump outlet pressure minus the suction pressure of the system. So, for an R-22 system operating withe a suction pressure of 70 psig, the oil pump outlet pressure should be at least 100 psig. It seems that you do not have sufficient pump pressure. Check the oil pump wiring before condemning the pump. Also, check the oil pressure switch. It is a differential control with 2 inputs: One providing the system's suction pressure and the other providing the pump outlet pressure.

Techman

Oil pump press.

This recip compressor , is there a strainer in the outlel of the  suction service valve ? Like on a Copelametic! Most  "oil pressure failure safety devices " get the low side pressure reading from the comp crankcase pressure . So, something in the suction line can drop the crankcase press alot . What press's do you have? Can you get crankcase press also? What is the motor pak  ?