| Feedwater Heater
- A feedwater heater is a small, unfired pressure vessel that uses
exhaust steam to preheat incoming feedwater, maximizing efficiency
be making use of the waste heat in the steam. These are typically
either a steam chamber within the engine frame that a water pipe
passes through, or a separate tank with either water or steam passages.
The feedwater heater typically was connected to a pump rather than
an injector, as the water expands as it heats, and could run backwards
through an injector.
Like most parts of a boiler, a feedwater
heater is subject to sediment, and needs to be flushed out regularly.
Most are equipped with drain cocks, and the one that drains the
steam section should generally be left open, otherwise the exhaust
line will tend to accumulate condensed steam when the engine sits
idle, spraying it all over you and any bystanders when you start
the engine turning again.