Hartford loop[′härt·fərd ‚lüp]
A condensate return arrangement for low-pressure, steam-heating systems featuring a steady water line in the boiler.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
Hartford loop, Underwriters’ loop
An arrangement of the return piping connections to a steam boiler; used to balance pressures between the supply and return sides of the boiler and thus prevent boiler water from backing out of the boiler and into the return.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.