MG my man...
in defence of good ol Silky for raising the subject, I too have seen great variation in the application of said same proc. As for our "Little 320" well that explains the tone of your response and just to throw a few facts into the mix. Tha DC pump is a suction pump as you rightly stated and is submerged in the fule line, it ONLY operates when insufficent pressure is sensed. It is possible form my days of not paying attention in physics class that if sufficent weight is placed on a fluid in a line/pipe it will travel up hill..... now I am not saying that it is sufficent to supply the APU full time but maybe intermitently (large amounts of fuel in tank). I think that was what good ol Silky was refering to. If I'm wrong I'm sure the likes of you will let me know.
The other reason I have been so well informed by my techy friends is that it is a hell of a job to change this pump..
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Dont forget you wont be leaving empty handed!