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 fi lter for debris (see recommended
installation).
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
movement of internal parts.
5. Check for sticking ball check valves. If material being
pumped is not compatible with pump elastomers,
swelling 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 fl ows.
1. Check for pump cavitation; slow pump speed down to
allow thick material to fl ow 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,
swelling 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 fi lter 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 P4 and PX4 pumps 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 fl ow 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 fl uid discharge pressure or increasing the air inlet
pressure. The Wilden P4 and PX4 pumps run solely on
compressed air and do not generate heat, therefore
your process fl uid 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 abrasiveness of process fl uid all
affect the parts life of a Wilden pump. Periodic
inspections have been found to offer the best means
for preventing unscheduled pump downtime. Personnel
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.
WILDEN PUMP & ENGINEERING, LLC
18
WIL-10161-E-01
T R O U B L E S H O O T I N G
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
