Upstream Pressure and Vent

    The upstream pressure (P_0) is measured from here.   Before running the motor make sure the black valve (P_0) is closed along with the vent.  Once the motor is running open P_0 Valve to get pressure reading.   This value in shown on the right pressure gauge labeled  (0000) and is measured in inches of water (in.H2O).   Before slowing down or shutting off motor, close the P_0 Valve.  This will prevent water from entering the system.  Once the valve is closed open the vent valve to equalize the pressure to ambient.  Note that if there is water in tube connecting the P_0 to the inlet pipe, it may cause erroneous readings.  If this happens contact the lab assistant to empty.