Find out who the Super likes to use and thinks does a good job. This will save you significant brain damage when dealing with the building.
That said, Maccarone Plumbing does a lot of work on the Upper East Side. I haven't used them in the City, but we have used them extensively in the Country (i..e. Long Island) for more than 25 years. They have an extensive practice in the City. They aren't the cheapest, but they have always done meticulous, knowledgeable work for us and for the people that I have recommended them to. They're based in Glen Cove, Long Island. My experience over dozens of repairs, including some tricky ones, is that they come in, do the repair right the first time, and that item needs no further work or adjustment.
Maccarone Plumbing provides a full range of plumbing services. Call (516) 671-3232 for help ASAP! Established in 1934, we are the plumbing and HVAC contractors of choice in Nassau and Suffolk Counties, as well as the New York metropolitan area.
www.maccaroneplumbing.com