The primary function of this gas station dispenser is for fueling vehicles with an automatic nozzle. The fuel pump dispenser will build up pressure to 44 psi max and then be unable to pump anymore. No bypass is needed as the pump will not damage itself when the oil flow is stopped (usually by a nozzel) The pump should not be left on for a long period of time when restricted, as it will wear down the vanes, but it is ok for normal usage. Included with this pump are 2 straight hose barb fittings which use a viton oring to form a proper seal with the pump. Although the fittings on the pump are straight thread, most NPT fittings can be made to fit when using yellow teflon tape.