I've been lurking for ... two or three years? I can't remember. It's been awhile. Figure I'd finally register and give thanks to those who have answered all the questions that someone else asked... today was about unloaders. I thought I had 'em figured out, but I didn't. Had to go through about a dozen posts, and found most of what I was looking for. Also learned that the 5H unloader is different than the the 06D/E unloaders. We mainly use the suction pressure unloaders on the 06D/Es. I think there's a few hot gas bypass sprinkled about as well.
I work mainly with Carrier Carlyle 06E/D compressors with R22 (about 26 of them). I have two little Carlyles with 407A for the freezers. I also have two 5H models with R22 that fall under my belt. They are all water cooled condensor fed.
Anyway, thanks again.