ENGINE DIAGNOSTIC TOOLS
Section 4
DWYER SLACK TUBE® MANOMETER
DESCRIPTION
The manometer (Figure 13) is a "U" shaped tube with a
scale mounted between the legs of the "U". Where the
portability of the SE-2239 is not required, this manometer
can be used to measure either low pressure or vacuum
and may be filled with water or mercury. The Dwyer
Manometer filled with mercury can be used to calibrate
the 0-30 psi gauge of the SE-2239.
Figure 13. Slack Tube Manometer
"A" Dimension Indicates Total Fluid Column
Dwyer No. 121148
Order from: Dwyer Instruments, Inc.
P.O. Box 373
Michigan City, Indiana 46360
Phone: (219) 872-9141
FILLING
The manometer may either be filled with water, when
checking very low pressures, or with mercury, when
checking slightly higher pressures. Refer to the
Performance Data Guideline pages in Section 6 to
determine whether water or mercury should be used.
When filling with water, use only good drinking water
without additives
except
for
some
colored
water
vegetable dye which enables the tester to read the scale
easier. With both legs of the manometer open to the
atmosphere, fill the tube until the top of the fluid column
is near the zero mark on the scale. Shake the tube to
eliminate any air bubbles.
When using mercury, the quantity of fluid needed may be
found in the Operating Range and Mercury Fill Chart.
Use
triple
distilled
mercury
to
minimize
tube
discoloration.
IMPORTANT
NEVER
USE
AN
ANTI-FREEZE
SOLUTION, SODA POP, TONIC, ETC.
THE INCREASE IN DENSITY CAUSES
FALSE READINGS.
OPERATING RANGE AND MERCURY
FILL CHART
Required
Operating
Ounces
Tool No.
Range
of Mercury
Inches of Water or Mercury
Dwyer No. 1211-48
24"-0-24"
22-1/2
INSTALLING AND READING
1.
Support the manometer in a vertical position. Be
sure the fluid is at the zero mark on the scale.
2.
Connect one leg of the manometer to the source
of the pressure or vacuum. Be sure the other
leg is open to atmosphere.
3.
Start the engine and when the engine is in the
proper operating condition as specified in
Performance Data Guideline pages, observe the
manometer.
CGES-240-4
Printed in United States of America
Page 18
