ENGINE DIAGNOSTIC TOOLS Section 4 4. After   about   two   minutes,   record   the   average position  the  fluid  level  is  above  and  below  the zero  mark.    Add  the  two  figures  together.    The sum of the two is the total column of fluid. NOTE:   At times both columns of the manometer will not travel the same distance.  This is of no concern to the tester as long as the leg not connected to the pressure or vacuum source is open to the atmosphere. 5. If  it  is  necessary  to  convert  from  the  column  of fluid     to     psi     or     kPa,     refer     to     the     "Metric Conversion Factor Chart" in Section 11. CLEANING 1. Wash the tube thoroughly with a little pure soap and water.  Avoid liquid soaps and solvents. 2. Dry thoroughly before refilling with mercury. CALIBRATING THE PRESSURE TEST KIT (SE-2239) USING THE DWYER SLACK TUBE® MANOMETER 1. The  hand  operated  pressure  pump  on  the  SE- 2239 is directly connected to the 0-15 psi gauge when the test kit is received.  Remove the nylon line  connecting  the  pressure  pump  to  the  0-15 gauge and reconnect the line to 0-30 psi gauge. Connect    the    0-15    gauge    to    the    0-15    panel connector. Now     the     hand     operated     pump     is     directly connected to the 0-30 gauge.  When the pump is operated and no leaks are present at the tubing connectors,  panel  quick  disconnects,   or   within the  pump,  a  pressure  will  build  on  the  gauge.  If the  gauge  shows  a  pressure  build-up  and  then falls off, a leak is present and must be corrected before  proceeding.    Replace  gauges  with  bent needles,  broken  cover  glass,  or  gauges  that  do not operate when pressure is applied. 2. Prepare the manometer for use by removing the manometer from its carrying case and attaching the  manometer  to  a  steel  surface.  Magnets  at the    back    of    the    manometer    will    hold    the manometer  in  a  vertical  position.  Note  that  the manometer has a 90 degree fitting at the top  of each column. Remove one 90 degree fitting, check valve, and cork to fill the manometer with mercury. Loosen the  other  90  degree  fitting  to  vent  the  opposite column    to    the    atmosphere.        Add    sufficient mercury to approximately reach the zero mark in both columns.  Slide the center measuring scale up or down until the zero mark on the scale is at the  top  of  both  columns  of  mercury.    This  will "zero"  the  manometer  for  reading   pressure   or vacuum.      Since   mercury   has   a   high   surface tension,  always  read  the  manometer  column  at the  highest  point  of  the  mercury.    If  water  were used     in     the     manometer,     always     read     the manometer   column   at   the   lowest   point   of   the water.      Install   the   removed   90   degree   fitting, check    valve,    and    cork    but    do    not    tighten completely.  The 90 degree fitting must be loose enough    to    keep    the    column    vented    to    the atmosphere to measure accurately. 3. To  determine  the  accuracy  of  the  0-30  gauge, connect  a  quick  disconnect  at  the  0-30  gauge panel    opening.        Attach    tubing    to    the    quick disconnect and hook up tubing to one side of the mercury   manometer.      At   this   point,   both   90 degree     fittings     are     loose.          One     fitting     is connected  to  the  tubing  and  one  side  is  vented to atmosphere. Check to see that the manometer is still zeroed. Operate   the   hand   pump   and   pressure   will   be read on the 0-30 gauge and also on the mercury manometer.    Test  for  air  leakage  in  the  tubing and connectors by watching the manometer and the gauge.  A drop off in the manometer reading or  gauge  indicates  an  air  leak  which  must  be corrected before proceeding. 4. Read manometer as follows: Operate  the  hand  pump  until  the  gauge  reads exactly   six   pounds.      Read   the   corresponding mercury    manometer    pressure    by    adding    the heights   of   the   two   columns   of   mercury.      A difference  in  the  height  of  the  columns  caused by  slight  variations  in  the  tubing  diameter  does not effect the accuracy of the manometer. 7.65    inches    of    mercury    plus    7.5    inches    of mercury equals 15.15 inches of mercury. continued on next page CGES-240-4 Printed in United States of America Page 19