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
