(under subclass 412) Feed water heaters which are heated by furnace gases only.
(1) Note. See the structural subclasses under the different types of boilers for feed heaters heated by furnace gases where the heater forms a part of the boiler, and boiler water circulates therethrough other than when the feed water is being fed to the feed water heating section and not merely as an alternate operation. For certain specialized feed heaters see "Search this class" below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
371, and the subclasses listed in the search notes thereunder, for water grates that serve as feed water heaters.
412, and the subclasses listed in the search notes thereunder for further directions as to feed water heaters.
