=The Heater= is used on an engine in connection with a boiler for
heating the feed water before it enters the boiler under steam
pressure. It is usually constructed of a shell of cast or boiler iron
into which live or exhaust steam is admitted. This shell usually
contains a series of pipes or a coil of pipe, through which the feed
water is forced by the pump, the water thereby being heated to a high
temperature before entering the boiler.