We have a small booster compressor that we use to run a post pasteurizer @ 15 degrees F and a small cooler @0 degrees. Our high stage runs @ 28 psig and our booster is running @ 15 psig, Both evaporators are flooded! Our high stage compressors work off of a lead/lag-step up/down system via supervisory computer control, our booster is variable frequency drive controlled!

Here is the issue that i am trying to figure out. Instead of the booster compressor adjusting its slide valve in response to load or lack of load, it runs @ 100 percent at all times until it reaches the low suction cut out, then cycle's on and off! This does not seem like an ideal set up to me.

Here is the question. Where would you start? With the VFD or compressor set-points?

This is an FES gs series compressor with a micro 3 panel. Thanks, Tim