Oil Return

tomd7735

I have to agree with RW. I worked for Hussman on supermarket 'rack' systems with 5-8 compressors on each rack. Equalizer copper tubing was a given. Just make sure the floats and needles and needle jets are clean and undamaged/operable. When the crankcase floats are in good shape, they feed oil as necessary. Make sure you're not stacking oil in a trap, or an evap coil with a bad TXV) A plus with this setup, is you can add oil in one place now. Of course with 06D's or 08D's, there's an oil level sight glass in the crankcase you can check, they should be equal: 1/2 - 5/8ths of glass hgt.

Larry_43

Oil in 404a

Professor:

I have a low temp system with 404a refrigerant in it. One copland compressor one Blizer they are staged compressor.
Aux Condnsing Unit
MD # VLX60L52
S/N# 86L1347
The Blizer is a replacement for an older copland they have a common dischage header into the condenser. Off the discharge of each compressor there is an oil sperator tied into each one of it's own compressor. The problem is that when the 1st stage calls it allows the oil to accumalate into the 2nd stages oil sperator which causes an over filled copressor with oil on a call for cooling which causes oil failure. They thought if they put check valves in it, it would not allow the oil to built up. But I think it will still weep into it because it is oil. They know they should have put in a single oil sperator but that is hindsight now. However I was thinking an equalizing line between the two compressor may reslove the problem. I am just looking for a reason why it would or would not work

Thanks

Larry

Unknown

Oil Slugger

Hussmann Parallel Racks used a simple equalizer line between the compressor for years with no problems. The line connected at the oil fill near the sight glass. For your situation you could add a oil tank and let the separators feed into the oil tank and then let the oil tank feed the oil floats on the compressors. This would be the fix on this system since you already have oil controls on the compressors. I gotta ask did we slug out any compressors on this system?

Larry_43

RW:

Not yet but I think it is just a matter of time. That is what I was thinking about was how I have seen Hussmann and
carrier use the equalizing line on their compressor racks. That is probably the simpleous sulution isn't it

Thanks