strainer blockage. If cleaning of strainer does not decrease temperature check the seal fluid line for
blockage.
Spin-on Oil Filter (if installed)
If you notice that the operating temperature of your system steadily increases, change the spin-on filter.
Separator Element
The separator elements are located in the separator reservoir. Its purpose is to remove the oil from the
discharge air. Replace the element every 10,000 hours or once a year. Earlier replacement may be
necessary when the back-pressure is higher than 4 psig. High back-pressure is a result of dirt build-up on
the separator element due to oil varnish, or contaminated inlet gas stream. Replacement may vary
depending on application.
NOTE: Thread-in style filters are installed hand-tight as an oil filter. Do not over-tighten with a
wrench.
Separator Element Oil Return Line
The separator element oil return lines are 1/4” to 3/8” transparent tubing. The purpose of these lines is to
remove excessive oil build-up from inside the separator and separator element. If excessive smoking or oil
mist is present, check the oil return lines for blockage and replace if necessary. Also check that the steel
section of oil return line located on top of the separator reservoir is cut at a 45° angle and is touching the
bottom of the separator element.
Mechanical Shaft Seals
All DEKKER oil-sealed liquid ring vacuum pumps are fitted with mechanical shaft seals. Mechanical seals
do not require maintenance unless there is more than a small amount of leakage. To define this we
differentiate between the following:
Weepage:
Mechanical seals work by having two flat surfaces pushed together by axial force from the
closing mechanism and by product pressure in the seal chamber. When the seal is in operation, the seal
fluid lubricates the tow faces. This thin film of lubrication protects the faces of the seal from heat and
excessive wear, but it can also allow for a small amount of leakage across the seal face. This small
leakage is called a “weep”. While a weep has rather arbitrary limits, it is commonly considered to be a
leakage rate of less than one drop of liquid every minute. Seal weeps are not covered under warranty.
Leakage:
a leakage rate of more than one drop per minute is considered to be a “leak”. Seal leakage is
normally a result of a build-up of abrasive particles carried over in the pump suction. These particles cause
excessive wear on the seal faces. Leakage caused by wear and tear is not covered under warranty.
Seal replacement is addressed in the assembly and disassembly instruction for the specific pump model
used. Consult factory for assistance.
MAINTENANCE SCHEDULE
To help ensure trouble free system operation, a basic maintenance schedule consisting of the following
system checks is recommended.
First 8 hours operation
Check oil level and inlet filter element if installed. Clean strainers and remove temporary inlet screen.
Check for water in sight gauge and drain if necessary. Check piping for signs of oil leakage and tighten if
necessary.
500 hours operation
Under normal operating conditions repeat 8 hour check procedure as described above
1000 hours operation
Check back-pressure on separator element; it should not exceed 4 psig. Change separator element if back-
pressure exceeds 4 psig. Also check discharge pipe system for blockage.
Clean or replace inlet filter element every 1000 to 3000 hours depending on application or if excessive
pressure drop is noticed.
Remove debris from pump housing, motor fan guard and heat exchanger.
1,000-3,000 hours of operation
Applicable to pumps equipped with grease fittings located on each bearing housing. Grease bearings with
a #2 quality lithium grease. Do not over-grease, 3 to 4 pumps with a grease gun is sufficient under normal
conditions.
Dekker Vacuum Technologies, Inc. – Vmax/13
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