Flooded Evaporator Oil Return

[posershadow]

I'm getting ready to put together a flooded system with R134a. I've heard of issues in the past in terms of getting enough liquid head to drive the oil back to the screw so therefore I'm interested in an eductor. The only problem is, I'm not really sure what size eductor I should be looking for. It doesn't seem like there is any published rules for estimating the size that it should be. My system is about an 85 ton with the evaporator running at 36F. The other question is related to the sizing of the solenoid valves, because I'm really not sure what kind of return rate would be common on a system this size to ensure sufficient oil return. I'm sure it's more of a personal preference in terms of sizing some of these things, but I have no experience with oil return to know what does and doesn't work.

[posershadow]

Anything?
Even just a guess of what the refrigerant/oil return rate should be would be helpful. Obviously I don't want to bleed too much back to the compressor and start killing my capacity. There must be eductors out there in the field on some of these flooded systems. I'm only looking for a ballpark number.