Oil migration problems

[barrymac82]

Hey everyone, looking for some tips / advice regarding oil migration problems on a water cooled chiller.

We have an old Trane system that has been converted from R22 to R417A. It utilises a sea water cooled condensor potable water evaporator. When our compressor runs fully loaded the oil seems to migrate into the condensor without coming back into the crankcase. There is adequate oil pressure protection but needless to say this is causing a few problems. However, when the system runs on half load, the oil migrates back to the compressor no problem. We have totally overhauled the system recently but fear that the same problem could arise. It was suggested that our TEV may require a bigger orifice. Any thoughts?

1st post guys, all feedback is much appreciated!

:D

[Grizzly]

Hi Barry
I have to say your post is a Little confusing.
I have had a situation on a screw pack where the coalescer (not sure of the spelling?) mesh was the wrong size.
So when the comp was running a high load / discharge Pressure.
Instead of the oil particles within the discharge gas, being trapped by the mesh. Forming droplets of sufficient size, that the oil drops of pooling below. As should happen.
The oil particle were being blasted through the mesh and on onto the system.
It is just possible the synthetic oil I assume you are using is not compatible with the oil recovery system fitted.
As this would of been designed for a different oil.
This is just a theory, but check out your oil options, it may make a difference say to go for a semi synthetic?
Hope this is of assistance?
Grizzly

[barrymac82]

Thanks for the reply to my 1st post Grizzly, I agree that it appears confusing!

We have checked the oil compatibility with R417A and it is fine. We currently use a semi-synthetic oil in Shell Clavus Oil SD22-12.

A long term option is to fit an oil trap / return line.

[frozenatsea]

Can you post the blueprint of your system and what mean "TEV":)

[NoNickName]

You ended up in the trap of retrofit drop-in gases. Oil carry over is to be expected increasing after a retrofit with R417, R422 and R427 refrigerants.
The next step is oil and refrigerant leakages from o-rings. Been there, done that. Nothing you can do except, as suggested, increase the oil separation with an extra oil coalescer / strainer.

[serviceman]

which model of machine is? I understand that reciprocating compressor is? the expansion valve operates correctly