NTI Boilers’ S20W high-performance wall-mounted indirect water heater features space-saving installation flexibility, and offers heating contractors multiple benefits for a variety of new installations as well as for retrofit projects.  Featuring an industrial size stainless-steel coil, and with its capability of 445 gph first-hour recovery rate, the 20-gal. S20W exceeds most industry standard 50- and 65-gal. indirect tanks, the company points out.