Cause some gas is just going round and round, the compressor is not loaded as much as it would be if the gas was going through it. You don't open recycles when you're loading up, right. And, if you are talking about recycling for surge control, then the compressor is in the process of unloading itself anyway. "A number of conditions can lead to this (surge) phenomenon, but it primarily occurs under conditions in which the compressor is overloaded beyond its ability to move more gas. Essentially, the back pressure of the compressed air that is expelled from the compressor exceeds the compressor's maximum capacity." ... and flow reverses.