I've heard of them on low temp compressors before but never seen them. I have a low temp 5H120 that I'm told has a history of "BAKING" the compressor. The maint. staff at this site has told me that once or twice a year the compressor is changed and they have a spare on hand. they send the cooked one out to a local rebuilder and it has been this way for many years. This system cools glycol to -22deg.C, that is used to cool chemical reactions thru heat exchangers during mixing. My first check, on an 80deg day had head temps around 235deg. my superheat at the compressor is only 20/25deg. and the eevs (4) all seem accurate and set at 3deg. . liquid sub-coolers (1 each evap) and not much more separate the evaps from the comp. I have requested some guidance from Carlyle and expect a response later this week. I'm not sure "head coolers " are even a good idea yet, seems like there may be more going on here that I haven't figured out . Maybe a different refrigerant, currently using 408-a, I can't believe this system was designed to be like this. And where does the water come from? another chiller? This has the makings of a real clusterf___, and I don't give-up until they stop paying me. "my shrink told me that one"