www.phcppros.com/articles/3118-tankless-replacement

Tankless replacement
January 3, 2015
New EZTR40 condensing tankless water heater for residential applications replaces a conventional 40-gal tank-type water heater for 2-bath residences in warm-weather climates. Easy replacement using 2" flexible polypropylene tubing that is threaded directly through the existing B-Vent; water connections are located on the top; the same 1/2" gas line.
Manufacturer Name: Noritz