Wanted to get a little knowledge from you guys on Yorks oil return system on a YT. I recently worked on a G design series, R123, YT machine. The machine experienced oil loss, and after I inspected this unit, I found one of the oil return eductors plugged up. I cleaned both eductors and bench tested them. When I had the eductors on the bench, I put 10 psig nitrogen on the motive force connection and a vacuum gauge on the pickup line showed 6.6 vacuum on a new eductor and on an old one, wth the eductor that was fouled at 4.5 vacuum. I could not find a different part number for these eductors, so I asssume that both are the same eductor. Got them cleaned and got great oil returen, pulling the oil out that I added to get it online, watched discharge temps come up and evap approach get tighter.
Incidentally, the eductor in question was the upper eductor that pulls from the "suction cover"(Trane term, sorry).
This leads to my first question. This oil port at the impeller inlet, is it at a pressure that is vented DIRECTLY to the impeller inlet, in that case, being at the lowest system pressure possible, or is it vented to the pressure before the PRVs, thus being not as low as inlet pressure at full PRV closed state?
Next question. This is a YT and looking at an overhaul guide I see what is listed as a High Pressure Seal, consisting of 3 parts: an oil seal retaining ring, a flat washer, and a seal ring. Does this assembly do the same job, effectively, as a balance piston assembly on a YK machine, and a Lab seal, on a CVH trane machine, that is, minimize oil sump pressurization?
This unit is not experiencing an over pressurized sump, and I have verified the vent solenoid operation. For you York techs, what pressure would you gauge the sump pressure against other than evap pressure? I noticed on this machine, and others I have overhauled in the past, an allen plug up on the compressor case, in this unit, opposite the vent valve piping. Do you guys ever use this port for trouble shooting?
What pressure limit can the eductors effectively return oil against? Thanks for the replies.