Re: Stuff Happens
"This allowed the engine to draw fuel from a local header tank or the main tank."
At bigger blue, the second smaller tank was to provide enough fuel to run the system should a power failure occur right in the middle of the twice-yearly flush & fill of the main tank. The "small" tank was only 300 gallons, the large tank was in the 25,000 gallon range (both numbers from memory). We had a small fleet of trucks in to pump the old fuel out, and then the new fuel in. Took pretty much all day.
Most modern diesel generators have self-bleeding fuel systems. Thankfully.