sb1dl4sm-REV0108 Models SB1-A & SB25A Page 5
PILOT VALVE ACTUATOR
Bushings for the pilot valve actuators are held in the inner chambers with retain-
ing rings. An o-ring is behind each bushing. If the plunger has any sideways motion,
check o-rings and bushing for deterioration or wear. The plunger may be removed
for inspection or replacement. First remove the air distribution valve body and the
pilot valve body from the pump. The plungers can be located by looking into the
intermediate. It may be necessary to use a ne piece of wire to pull them out.
The bushing can be turned out through the inner chamber by removing the outer
chamber assembly. Replace the bushings if pins have bent.
SERVICE INSTRUCTIONS: TROUBLE SHOOTING
Pump will not cycle
A. Check to make sure the unit has enough pressure to operate and that the air inlet
valve is open.
B. Check the discharge line to insure that the discharge line is neither closed nor
blocked.
C. It the spool in the air distribution valve is not shifting, check the main spool. It must
slide freely.
D. Excessive air leakage in the pump can prevent cycling. This condition will be evident.
Air leakage into the discharge line indicates a ruptured diaphragm. Air leakage from
the exhaust port indicates leakage in the air distribution valve. See further service
instructions.
E. Blockage in the liquid chamber can impede movement of diaphragm.
Pump cycles but will not pump
A. Suction side of pump pulling in air. Check the suction line for air leaks and be sure that
the end of the suction line is submerged. Check ange bolting. Check valve anges
and manifold to chamber ange joints.
B. Make certain the suction line or strainer is not plugged. Restriction at the suction is
indicated by a high vacuum reading when a vacuum gauge is installed in the suction
line.
C. Check valves may not be seating properly. To check, remove the suction line and cover
the suction port with your hand. If the unit does not pull a good suction (vacuum), the
check valves should be inspected for proper seating.
D. Static suction lift may be too high. Priming can be improved by elevating the suction
and discharge lines higher than the check valves and pouring liquid into the unit
through the suction inlet. When priming at high suction lifts or with long suction lines
operate the pump at maximum cycle rate.
Low performance
A. Capacity is reduced as the discharge pressure increases, as indicated on the perfor-
mance curve. Performance capability varies with available inlet air supply. Check air
pressure at the pump inlet when the pump is operating to make certain that adequate
air supply is maintained.
B. Check vacuum at the pump suction. Capacity is reduced as vacuum increases. Re-
duced ow rate due to starved suction will be evident when cycle rate can be varied
without change in capacity. This condition will be more prevalent when pumping vis-
cous liquids. When pumping thick, heavy materials the suction line must be kept as
large in diameter and as short as possible, to keep suction loss minimal.
C. Low ow rate and slow cycling rate indicate restricted ow through the discharge
line. Low ow rate and fast cycling rate indicate restriction in the suction line or air
leakage into suction.
D. Unstable cycling indicates improper check valve seating on one chamber. This condi-
tion is conrmed when unstable cycling repeats consistently on alternate exhausts.
Cycling that is not consistently unstable may indicate partial exhaust restriction due to
freezing and thawing of exhaust air. Use of an air dryer should solve this problem.
For additional information, see the Warren Rupp Troubleshooting Guide.
WARRANTY
This pump is warranted for a period of ve years against defective material and
workmanship. Failure to comply with the recommendations stated in this manual voids
all factory warranty.
RECOMMENDED WARREN RUPP
ACCESSORIES TO MAXIMIZE
PUMP PERFORMANCE:
• Tranquilizer
®
Surge Suppressor.
For nearly pulse-free ow.
• Warren Rupp Filter/Regulator.
For modular installation and
service convenience.
• Warren Rupp Speed Control.
For manual or programmable
process control. Manual adjustment
or 4-20mA reception.
For more detailed information on
these accessories, contact your local
Warren Rupp Factory-Authorized
Distributor, or Warren Rupp corporate
headquarters or visit:
www.warrenrupp.com
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