I work for a contractor that services heat transfer tubes.
Basically I work on these things. I clean the scale (from circulating water) or product out of them increasing the heat transfer back to original specification. Also I test and repair them, pull the tubes out with heavy machinery and replace them. Sometimes they are so bad I use this big drill rig and drill them out. These exchangers are often massive and 30+ feet long.

Most of the time I work on the condenser in power plants.

I can't post any pictures of my equipment, at least I don't think I can.