Posted for bob mackey <n103md@yahoo.com>:

 Terrence O'neill wrote:

  > Question: For hot situations like Frded related, does
  > it sound like a good idea to install a low pressure transfer
  > pump to assure moving fuel from the header through the 'off'
  > boost pump to the engine-driven pump?

  I have not found that necessary with my L235/O-320. The bottom
  of the header tank is well above the Facet boost pump in my
  installation. Gravity flow through the Facet pump, gascolator,
  filter, engine pump, and all hoses is about 50 gph - well in
  excess of the max fuel flow of the engine.

  My left and right transfer pumps are located at the lowest
  point on the floor, just in front of the middle of the spar.
  That is much improved from the previous situation, in which
  the single transfer pump pulled from whichever wing had
  more air in it.

  > My Airflow boost pump is on-off, and is located after the
  > filter which is between the header and the boost pump.
 
  Rather than add the complications of another pump, have you
  considered moving the existing pump to before the filter?
  That should reduce the risk of filter cavitation.

  -bob