07.14 When is a return flow pump needed and how is it sized?

A return flow pump may be required for several reasons: (a) day tank overflow protection as discussed at Item 7.05 above, (b) day tank high temperature as discussed at Item 7.10 above, and (c) as a means of lowering the fuel level in the day tank for initial and periodic testing of the system. Sizing of the pump is usually governed by the overflow protection function.