WILDEN PUMP & ENGINEERING, LLC
22
WIL-10131-E-01
Pump will not run or runs slowly.
1.
Ensure that the air inlet pressure is at least 0.4 bar (5 psig)
above startup pressure and that the differential pressure
(the difference between air inlet and liquid discharge
pressures) is not less than 0.7 bar (10 psig).
2. Check air inlet filter for debris (see recommended instal-
lation).
3. Check for extreme air leakage (blow by) which would
indicate worn seals/bores in the air valve, pilot spool and
main shaft.
4. Disassemble pump and check for obstructions in the air
passageways or objects which would obstruct the move-
ment of internal parts.
5. Check for sticking ball check valves. If material being
pumped is not compatible with pump elastomers, swell-
ing may occur. Replace ball check valves and seals with
proper elastomers. Also, as the check valve balls wear
out, they become smaller and can become stuck in the
seats. In this case, replace balls and seats.
6. Check for broken inner piston which will cause the air
valve spool to be unable to shift.
7. Remove plug from pilot spool exhaust.
Pump runs but little or no product flows.
1. Check for pump cavitation; slow pump speed down to
allow thick material to flow into the liquid chambers.
2. Verify that vacuum required to lift liquid is not greater
than the vapor pressure of the material being pumped
(cavitation).
3. Check for sticking ball check valves. If material being
pumped is not compatible with pump elastomers, swell-
ing may occur. Replace ball check valves and seals with
proper elastomers. Also, as the check valve balls wear
out, they become smaller and can become stuck in the
seats. In this case, replace balls and seats.
Pump air valve freezes.
1. Check for excessive moisture in compressed air. Either
install a dryer or hot air generator for compressed air.
Alternatively, a coalescing filter may be used to remove
the water from the compressed air in some applications.
Air bubbles in pump discharge.
1. Check for ruptured diaphragm.
2. Check tightness of outer pistons. (Refer to Section 8C.)
3. Check tightness of clamp bands and integrity of o-rings
and seals, especially at intake manifold.
4. Ensure pipe connections are airtight.
Product comes out air exhaust.
1. Check for diaphragm rupture.
2. Check tightness of outer pistons to shaft.
OPERATION: The P8 and PX8 are pre-lubricated, and do
not require in-line lubrication. Additional lubrication will not
damage the pump, however if the pump is heavily lubricated
by an external source, the pump’s internal lubrication may be
washed away. If the pump is then moved to a non-lubricated
location, it may need to be disassembled and re-lubricated as
described in the ASSEMBLY/DISASSEMBLY INSTRUCTIONS.
Pump discharge rate can be controlled by limiting the volume
and/or pressure of the air supply to the pump (preferred
method). An air regulator is used to regulate air pressure.
A needle valve is used to regulate volume. Pump discharge
rate can also be controlled by throttling the pump discharge
by partially closing a valve in the discharge line of the pump.
This action increases friction loss which reduces flow rate.
(See Section 5.) This is useful when the need exists to control
the pump from a remote location. When the pump discharge
pressure equals or exceeds the air supply pressure, the
pump will stop; no bypass or pressure relief valve is needed,
and pump damage will not occur. The pump has reached a
“deadhead” situation and can be restarted by reducing the
fluid discharge pressure or increasing the air inlet pressure.
The Wilden P8 and PX8 pump run solely on compressed
air and does not generate heat, therefore your process fluid
temperature will not be affected.
MAINTENANCE AND INSPECTIONS: Since each application
is unique, maintenance schedules may be different for every
pump. Frequency of use, line pressure, viscosity and abra-
siveness of process fluid all affect the parts life of a Wilden
pump. Periodic inspections have been found to offer the best
means for preventing unscheduled pump downtime. Person-
nel familiar with the pump’s construction and service should
be informed of any abnormalities that are detected during
operation.
RECORDS: When service is required, a record should be
made of all necessary repairs and replacements. Over a
period of time, such records can become a valuable tool for
predicting and preventing future maintenance problems and
unscheduled downtime. In addition, accurate records make
it possible to identify pumps that are poorly suited to their
applications.
S U G G E S T E D O P E R A T I O N & M A I N T E N A N C E
T R O U B L E S H O O T I N G
