Serious Wrote:
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> That detail about standard feedwater heaters not
> functioning without an open throttle is just the
> kind of thing I'd fail to consider.
>
> Not at all familiar with feedwater injectors, will
> do some reading--thanks again.

Careful,,,,,I didn't say "feedwater injectors". I said Exhaust Steam Injectors, like the Elesco Exhaust Steam Injector, which is designed with an internal change-over valve that supplies exhaust steam OR live boiler steam to preheat the feedwater. Thus, if the throttle is closed, i.e. no exhaust steam, then the change-over valve re-positions in order to supply boiler steam for preheating the feedwater. When the throttle is reopened and exhaust steam is again supplied, the change-over valve does its thing.