Oil Non returning to compressor

[texanul]

I have a cold room with a bitzer compressor with r404 refrigerant working fine for over 3 years.After that time the customer say the cold room is broken and i found a broken compressor(mecanical) and no oil in the compressor. I change the comressor with a new one charge again and after 2 days found the compressor with no oil in the glass level .I must say the evaporator is above the condenser and i have oil traps on the pipes. Please tell me where is all the oil and why is no`t returning to the compressor.

[coolhibby1875]

choked seperator or is thre a solenoid valve on the oil return line that should open when the comp is running.

[Sandro Baptista]

Does the system have oil return solenoid valve? Is it energized/opened? Do you feel the oil return line hot or is it at ambient temperature? If it isn't hot so that could mean that the oil return line is clogged.
The compressor has oil pump + MP54 ?

[Gary]

At this point we don't even know if it has an oil separator. Apparently it is a single compressor system... and that's about all we know. We need a much better description of the system, because we can't see it from here.

[spezi]

Problem solved ?
If theres no oil seperator then it sounds like it could be liquid washing the oil out, probably after the defrost. check it out !

[lowcool]

its even better when the things wired to cycle off compressor and solenoid at the same time with leakage across the solenoid valve.lol.

give me pump down anyday it beats a compressor change overnight!