Commercial plumbing repair. Repair leaks on a copper piping water line in the main lobby. I had to turn off the hot water to the entire first floor and drain the entire system to repair it. After the system was drained, I cut out the faulty 90 and replaced it with a new 1 1/2” copper pipe by using two 1 1/2” progress couplings and one 11/2” progress 90. Turned the water back on, checked for leaks, and emptied the air of the hot water line before turning the return pump back on. After a piping system inspection, I found it was holding with no leaks. The air was bled out of the system, and the return pump was working properly. I cleaned up the work area.