As found, GN2 flow through CP4's regeneration circuit was steady and indicated on the first scale graduation (12 SCFH x 100).  The dewar head pressure(s) were 10 psi and 12 psi as per the mechanical gauges -> I opened the Pressure Build valve 1 turn ccw and the dewar head pressure increased by 2 psi over 20 minutes.  Correspondingly, the GN2 regeneration flow increased to a varying 40 - 50 SCFH x 100.  I did not notice any reverse flow through the Fill Connection line.  The Regeneration Temperature decreased, as expected, with the increase in flow.  Even so, I don't feel comfortable leaving the site with the Pressure Build valve open as we have no way to remotely monitor the exhaust line pressure and I can't be sure that the dewar head pressure has stabilized.  As a compromise, I closed the Pressure Build valve and, instead, adjusted the dewar head pressure (a.k.a. vapor pressure) regulator (a.k.a. "economizer") 1/4 turn cw.  This should slowly increase the dewar head pressure a little over the next day or so and the regeneration flow should also increase a little as a result.