I work on lots of big roof top units. Roof-Paks, Intellipaks, etc. etc. I dabble in TAB work occasionally.
I get called out on smaller stuff pretty frequently, though. I don't do any refrigeration work, just HVAC stuff.
There's a handful of guys that handle the centrifugal and screw work. Hopefully, in time, I'll be able to work my way into that side. The larger and more complex the system, the more interesting it seems.
The split is a carrier condenser coupled with an ICE air rotation unit. The packaged units are mammoth. no pics yet, not sure if i can get those, and even then, I get confused with how to post them here.
I work mostly in high rise buildings and manufacturing plants with occasional heavy rooftops. Some small stuff on call duty. I like it all to be honest cause even the small stuff can challenge you like ZN010 controllers on a fan coil unit. Can't service them without Rover so not everyone can fix em. I even do a little project management here and there. We have to be more than just techs these days help out the management. Definitely love what I'm doing for now.
It's the variety that keeps this type of work from burning you out. We did a job at a Fish Farm in Nebraska where they were raising salmon. Used a 50 ton Trane scroll chiller to keep the water at 52 degrees. Now I can say I even "air conditioned" fish. Doing chiller work , we're usually worried about keeping the condenser side clean. At the fish farm....keeping the evap side clean was the fun part keeping fish guts and **** out of the tubes.
Reminds me of what I tell new kids when they ask me what I would consider a "big" AC unit. I tell them that you can tell if a unit is "big" if when you open the access door and reach around and find a light switch ... only "big" equipment has built in interior lighting Then they usually look at me like I'm crazy and ask if I'm joking about the lights
250 ton RTU's are not uncommon around here. Most are Mammoth, Use 2 supply fans and use Fusheng compressors. I know of a 930 ton split system. Also a mammoth. I think it was one of the largeset that Mammoth ever made.(It's sister unit is in Portland If I remember correctly.) This machine uses (6) 75HP supply fans and (6) Fusheng SR-5 compressors. The sky is probably the limit as far as unit size is concerned. Most manufacturers will also provide options as to what compressor or other components are used. This is usually a price point desition.