Wilden P4 series Instruction Manual

P4 Plastic Pump
EOM
Engineering
Operation &
Maintenance
wildenpump.com
Where Innovation Flows

SECTION 1 CAUTIONS—READ FIRST! ..............................................1
SECTION 2 WILDEN PUMP DESIGNATION SYSTEM.................................2
SECTION 3 HOW IT WORKS—PUMP & AIR DISTRIBUTION SYSTEM ................3
SECTION 4 DIMENSIONAL DRAWING ..............................................4
SECTION 5 PERFORMANCE
P4 Plastic Rubber-Fitted ....................................................5
P4 PlasticTPE-Fitted .......................................................5
P4 Plastic Reduced-Stroke PTFE-Fitted ........................................6
P4 Plastic Full-Stroke PTFE-Fitted ............................................6
Suction-Lift Curves .......................................................7
SECTION 6 SUGGESTED INSTALLATION, OPERATION & TROUBLESHOOTING........8
SECTION 7 DISASSEMBLY/REASSEMBLY..........................................11
Air Valve / Center-Section Disassembly ......................................14
Reassembly Hints &Tips ..................................................16
PTFE Gasket Kit Installation ................................................17
SECTION 8 EXPLODED VIEW & PARTS LISTING
P4 Plastic Full-Stroke, 3-Piece Center-Section .................................18
P4 Plastic Reduced Stroke, 3-Piece Center-Section .............................20
SECTION 9 ELASTOMER OPTIONS.................................................24
TABLE OF CONTENTS

CAUTION: Do not apply compressed air to the
exhaust port — pump will not function.
CAUTION: Do not over lubricate air supply —
excess lubrication will reduce pump performance.
TEMPERATURE LIMITS:
Acetal –29°C to 82°C –20°F to 180°F
Buna-N –12°C to 82°C 10°F to 180°F
Geolast®–40°C to 82°C –40°F to 180°F
Neoprene –18°C to 93°C 0°F to 200°F
Nordel®EPDM –51°C to 138°C –60°F to 280°F
Nylon –18°C to 93°C 0°F to 200°F
PFA –7°C to 107°C 45°F to 225°F
Polypropylene 0°C to 79°C 32°F to 175°F
Polyurethane –12°C to 66°C 10°F to 150°F
PVDF –12°C to 107°C 10°F to 225°F
Saniflex™ –29°C to 104°C –20°F to 220°F
SIPD PTFE with EPDM-backed 4°C to 137°C 40°F to 280°F
SIPD PTFE with Neoprene-backed 4°C to 93°C 40°F to 200°F
PTFE14°C to 104°C 40°F to 220°F
FKM –40°C to 177°C –40°F to 350°F
Wil-Flex™ –40°C to 107°C –40°F to 225°F
NOTE: Not all materials are available for all
models. Refer to Section 2 for material options
for your pump.
CAUTION: When choosing pump materials, be
sure to check the temperature limits for all wetted
components. Example: FKM has a maximum
limit of 177°C (350°F) but polypropylene has a
maximum limit of only 79°C (175°F).
CAUTION: Maximum temperature limits are
based upon mechanical stress only. Certain
chemicals will significantly reduce maximum safe
operating temperatures. Consult engineering
guide for chemical compatibility and temperature
limits.
CAUTION: Always wear safety glasses when
operating pump. If diaphragm rupture occurs,
material being pumped may be forced out air
exhaust.
Plastic series pumps are made of virgin plastic
and are not UV-stabilized. Direct sunlight for
prolonged periods can cause deterioration of
plastics.
WARNING: Prevent static sparking — If static
sparking occurs, fire or explosion could result.
Pump, valves, and containers must be grounded
when handling flammable fluids and whenever
discharge of static electricity is a hazard. To
ground the Wilden “Champ,” all clamp bands
must be grounded to a proper grounding point.
CAUTION: Do not exceed 8.6 bar (125 psig) air
supply pressure.
CAUTION: Before any maintenance or repair is
attempted, the compressed air line to the pump
should be disconnected and all air pressure
allowed to bleed from pump. Disconnect all
intake, discharge and air lines. Drain the pump by
turning it upside down and allowing any fluid to
flow into a suitable container.
CAUTION: Blow out air line for 10 to 20 seconds
before attaching to pump to make sure all
pipeline debris is clear. Use an in-line air filter. A
5µ (micron) air filter is recommended.
NOTE: When installing PTFE diaphragms, it is
important to tighten outer pistons simultaneously
(turning in opposite directions) to ensure tight fit.
NOTE: P4 PVDF and PFA pumps come standard
from the factory with expanded PTFE gaskets
installed in the diaphragm bead of the liquid
chamber, in the T-section and in the ball and seat
area. PTFE gaskets cannot be re-used.
NOTE: Before starting disassembly, mark a line
from each liquid chamber to its corresponding air
chamber. This line will assist in proper alignment
during reassembly.
CAUTION: The P4 plastic pump is not submersible.
CAUTION: Pumps should be flushed thoroughly
with water before installation into process line.
CAUTION: Tighten all hardware prior to
installation.
1
4°C to 149°C (40°F to 300°F) - 13 mm (1/2") and 25 mm (1") models only.
WIL-10160-E-10 1 WILDEN PUMP & ENGINEERING, LLC
Section 1
CAUTIONS—READ FIRST!

WILDEN PUMP & ENGINEERING, LLC 2 WIL-10160-E-10
Section 2
WILDEN PUMP DESIGNATION SYSTEM
NOTE: MOST ELASTOMERIC MATERIALS USE COLORED DOTS FOR IDENTIFICATION.
P4 PLASTIC
38 mm (1-1/2") Pump
Maximum Flow Rate:
352 lpm (93 gpm)
MATERIAL CODES
WETTED PARTS & OUTER PISTON
KK = PVDF / PVDF
PP = POLYPROPYLENE /
POLYPROPYLENE
TT = PFA / PFA
AIR CHAMBER/CENTER SECTION
A = ALUMINUM
C = PTFE-COATED ALUMINUM
L = ACETAL
S = STAINLESS STEEL
V = HALAR®-COATED ALUMINUM
CENTER BLOCK / CENTER SECTION
L = ACETAL
P = POLYPROPYLENE
AIR VALVE
L = ACETAL
P = POLYPROPYLENE
DIAPHRAGMS
BNS = BUNA-N (Red Dot)
BNU = BUNA-N, ULTRA-FLEX™
(Red Dot)
EPS = EPDM (Blue Dot)
EPU = EPDM, ULTRA-FLEX™
(Blue Dot)
FSS = SANIFLEX™
[Hytrel®(Cream)]
NES = NEOPRENE (Green Dot)
NEU = NEOPRENE, ULTRA-FLEX™
(Green Dot)
PUS = POLYURETHANE (Clear)
TEU = PTFE W/EPDM
BACKUP (White)
TSS = FULL-STROKE PTFE
W/SANIFLEX™ BACKUP
TSU = PTFE W/SANIFLEX™
BACKUP (White)
TWS = FULL-STROKE PTFE
W/WIL-FLEX™ BACKUP
VTS = FKM (White Dot)
VTU = FKM, ULTRA-FLEX™
WFS = WIL-FLEX™ [Santoprene®
(Three Black Dots)]
VALVE BALLS
BN = BUNA-N (Red Dot)
EP = EPDM (Blue Dot)
FS = SANIFLEX™
[Hytrel® (Cream)]
FV = SANITARY FKM
(Two White Dots)
NE = NEOPRENE (Green Dot)
PU = POLYURETHANE (Brown)
TF = PTFE (White)
VT = FKM (White Dot)
WF = WIL-FLEX™ [Santoprene®
(Three Black Dots)]
VALVE SEATS
K = PVDF
P = POLYPROPYLENE
T = PFA
VALVE SEAT O-RINGS
BN = BUNA-N
PU = POLYURETHANE (Brown)
TV = PTFE ENCAP. FKM
LEGEND
P4 / XXXXX / XXX /XX / XXX /XXXX
O-RINGS
MODEL VALVE SEATS
VALVE BALLS
DIAPHRAGMS
AIR VALVE
CENTER BLOCK OR CENTER SECTION
AIR CHAMBERS OR CENTER SECTION
WETTED PARTS & OUTER PISTON
SPECIALTY
CODE
(if applicable)
In the case where a center section is used instead of a center block, air chambers, and air valve,
the designation will be as follows: Polypropylene = PPP, Acetal = LLL
SPECIALTY CODES
0100 Wil-Gard II™ 110V
0102 Wil-Gard II™ sensor wires ONLY
0103 Wil-Gard II™ 220V
0206 PFA-coated hardware,
Wil-Gard II™ sensor wires ONLY
0502 PFA-coated hardware
0504 DIN flange
0506 DIN flange, PFA-coated hardware
0512 Adapter block, no muffler,Pro-Flo®,
center section
0513 SS outer pistons
0560 Split manifold
0561 Split manifold, PFA-coated hardware
0563 Split manifold, discharge ONLY
0564 Split manifold, inlet ONLY
0603 PFA-coated hardware, Wil-Gard II™ 110V
0604 DIN flange, Wil-Gard II™ 220V
0606 DIN flange, PFA-coated hardware,
Wil-Gard II™ 220V
0608 PFA-coated hardware, Wil-Gard II™ 220V
0612 Ultrapure, PFA-coated hardware,
male connections
0618 Ultrapure, PFA-coated hardware,
Wil-Gard II™ 110V, male connections
0622 Ultrapure, male connections
0624 Ultrapure, Wil-Gard II™ 110V, male connections
0660 Split manifold, Wil-Gard II™ 110V
0661 Split manifold PFA-coated hardware,
Wil-Gard II™ 110V

OPEN
CLOSED
OPEN
CLOSED
OUTLET
INLET
BA
OUTLET
INLET
OPEN
CLOSED
CLOSED
OPEN
BA
The Pro-Flo®patented air distribution system incorporates
three moving parts: the air valve spool, the pilot spool, and
the main shaft/diaphragm assembly. The heart of the system
is the air valve spool and air valve. As shown in Figure 1, this
valve design incorporates an unbalanced spool. The smaller
end of the spool is pressurized continuously, while the large
end is alternately pressurized and exhausted to move the
spool. The spool directs pressurized air to one chamber
while exhausting the other. The air causes the main shaft/
diaphragm assembly to shift to one side — discharging liquid on
one side and pulling liquid in on the other side. When the shaft
reaches the end of its stroke, it actuates the pilot spool, which
pressurizes and exhausts the large end of the air valve spool.The
pump then changes direction and the same process occurs in the
opposite direction, thus reciprocating the pump.
MAIN SHAFT
CENTER BLOCK
PILOT
SPOOL
SMALL END
END CAP
LARGE END
AIR VALVE SPOOL
MUFFLER
MUFFLER PLATE
The Wilden diaphragm pump is an air-operated, positive displacement, self-priming pump.These drawings show flow pattern through
the pump upon its initial stroke. It is assumed the pump has no fluid in it prior to its initial stroke.
Figure 1
OUTLET
INLET
OPEN
CLOSED
CLOSED
OPEN
BA
FIGURE 1 The air valve directs pressurized
air to the back side of diaphragm A. The
compressed air is applied directly to the
liquid column separated by elastomeric
diaphragms. The diaphragm acts as
a separation membrane between the
compressed air and liquid; a balanced
load removes mechanical stress from the
diaphragm. The compressed air moves
the diaphragm away from the center block
of the pump. The opposite diaphragm is
pulled in by the shaft connected to the
pressurized diaphragm. Diaphragm B is on
its suction stroke; air behind the diaphragm
has been forced out to the atmosphere
through the exhaust port of the pump.
The movement of diaphragm B toward the
center block of the pump creates a vacuum
within chamber B. Atmospheric pressure
forces fluid into the inlet manifold forcing
the inlet valve ball off its seat. Liquid is free
to move past the inlet valve ball and fill the
liquid chamber (see shaded area).
FIGURE 2 When the pressurized
diaphragm, diaphragm A, reaches the
limit of its discharge stroke, the air valve
redirects pressurized air to the back
side of diaphragm B. The pressurized air
forces diaphragm B away from the center
block while pulling diaphragm A to the
center block. Diaphragm B is now on its
discharge stroke. Diaphragm B forces the
inlet valve ball onto its seat due to the
hydraulic forces developed in the liquid
chamber and manifold of the pump.These
same hydraulic forces lift the discharge
valve ball off its seat, while the opposite
discharge valve ball is forced onto its seat,
forcing fluid to flow through the pump
discharge. The movement of diaphragm
A toward the center block of the pump
creates a vacuum within liquid chamber A.
Atmospheric pressure forces fluid into the
inlet manifold of the pump.The inlet valve
ball is forced off its seat allowing the fluid
being pumped to fill the liquid chamber.
FIGURE 3 At completion of the stroke, the
air valve again redirects air to the back side
of diaphragm A, which starts diaphragm
B on its exhaust stroke. As the pump
reaches its original starting point, each
diaphragm has gone through one exhaust
and one discharge stroke. This constitutes
one complete pumping cycle. The pump
may take several cycles to completely
prime depending on the conditions of the
application.
Right Stroke Mid Stroke Left Stroke
WIL-10160-E-10 3 WILDEN PUMP & ENGINEERING, LLC
Section 3
HOW IT WORKS—PUMP
HOW IT WORKS—AIR DISTRIBUTION SYSTEM

DIMENSIONS
ITEM METRIC (mm) STANDARD (inch)
A 394 15.5
B 79 3.1
C 287 11.3
D 465 18.3
E 528 20.8
F 122 4.8
G 287 11.3
H 300 11.8
J 137 5.4
K 287 11.3
L 236 9.3
M 180 7.1
N 203 8.0
P 10 0.4
DIN FLANGE
R 109 DIA. 4.3 DIA.
S 150 DIA. 5.9 DIA.
T 18 DIA. 0.7 DIA.
ANSI FLANGE
R 99 DIA. 3.9 DIA.
S 127 DIA. 5.0 DIA.
T 20 DIA. 0.8 DIA.
LW0496 REV. A
WILDEN PUMP & ENGINEERING, LLC 4 WIL-10160-E-10
Section 4
DIMENSIONAL DRAWINGS
P4 Plastic

Flow rates indicated on chart were determined by pumping water.
For optimum life and performance, pumps should be specified so that daily operation
parameters will fall in the center of the pump's performance curve.
Flow rates indicated on chart were determined by pumping water.
For optimum life and performance, pumps should be specified so that daily operation
parameters will fall in the center of the pump's performance curve.
Ship Weight ...... Polypropylene 16.8 kg (37 lb)
PVDF 21.3 kg (47 lb)
Air Inlet ................................... 13 mm (1/2")
Inlet ...................................... 38 mm (1-1/2")
Outlet ................................... 38 mm (1-1/2")
Suction Lift ........................ 4.88 m Dry (16')
7.92 m Wet (26')
Disp. per Stroke1.............. 1.19 L (0.314 gal)
Max. Flow Rate .............. 348 lpm (92 gpm)
Max. Size Solids.................. 4.8 mm (3/16")
1Displacement per stroke was calculated at
4.8 bar (70 psig) air inlet pressure against a
2 bar (30 psig) head pressure.
Example: To pump 159 lpm (40 gpm)
against a discharge pressure head of 2.7
bar (40 psig) requires 4.1 bar (60 psig) and
30.6 Nm3/h (18 scfm) air consumption.
(See dot on chart.)
Caution: Do not exceed 8.6 bar (125 psig)
air supply pressure.
Ship Weight ...... Polypropylene 16.8 kg (37 lb)
PVDF 21.3 kg (47 lb)
Air Inlet ................................... 13 mm (1/2")
Inlet ...................................... 38 mm (1-1/2")
Outlet ................................... 38 mm (1-1/2")
Suction Lift ........................ 3.96 m Dry (13')
7.92 m Wet (26')
Disp. per Stroke1.............. 1.18 L (0.311 gal)
Max. Flow Rate .............. 354 lpm (94 gpm)
Max. Size Solids.................. 4.8 mm (3/16")
1Displacement per stroke was calculated at
4.8 bar (70 psig) air inlet pressure against a
2 bar (30 psig) head pressure.
Example: To pump 42 gpm (159 lpm)
against a discharge pressure head of 2.7
bar (40 psig) requires 4.1 bar (60 psig) and
34 Nm3/h (20 scfm) air consumption. (See
dot on chart.)
Caution: Do not exceed 8.6 bar (125 psig)
air supply pressure.
WIL-10160-E-10 5 WILDEN PUMP & ENGINEERING, LLC
Section 5A
PERFORMANCE
P4 PLASTIC
RUBBER-FITTED
P4 PLASTIC
TPE-FITTED

Ship Weight ...... Polypropylene 16.8 kg (37 lb)
PVDF 21.3 kg (47 lb)
PTFE PFA 23.9 kg (52 lb)
Air Inlet ................................... 13 mm (1/2")
Inlet ...................................... 38 mm (1-1/2")
Outlet ................................... 38 mm (1-1/2")
Suction Lift ................. 3.05 m Dry (10' Dry)
7.47 m Wet (24.5')
Disp. per Stroke1..............0.53 L (0.139 gal)
Max. Flow Rate .............. 261 lpm (69 gpm)
Max. Size Solids.................. 4.8 mm (3/16")
1Displacement per stroke was calculated at
4.8 bar (70 psig) air inlet pressure against
a 2 bar (30 psig) head pressure.
Example: To pump 125 lpm (33 gpm)
against a discharge pressure head of 2.7
bar (40 psig) requires 4 bar (58 psig) and
45 Nm3/h (27 scfm) air consumption. (See
dot on chart.)
Caution: Do not exceed 8.6 bar (125 psig)
air supply pressure.
Flow rates indicated on chart were determined by pumping water.
For optimum life and performance, pumps should be specified so that daily operation
parameters will fall in the center of the pump's performance curve.
Flow rates indicated on chart were determined by pumping water.
For optimum life and performance, pumps should be specified so that daily operation
parameters will fall in the center of the pump's performance curve.
P4 PLASTIC
REDUCED-STROKE
PTFE-FITTED
P4 PLASTIC
FULL-STROKE
PTFE-FITTED
PERFORMANCE
Ship Weight ...... Polypropylene 16.8 kg (37 lb)
PVDF 21.3 kg (47 lb)
PTFE PFA 23.9 kg (52 lb)
Air Inlet ...................................13 mm (1/2”)
Inlet ......................................38 mm (1-1/2”)
Outlet ...................................38 mm (1-1/2”)
Suction Lift ........................ 4.7m Dry (15.3’)
9.3 m Wet (30.6’)
Disp. per Stroke1....................1.0 L (.27 gal)
Max. Flow Rate ........... 352 lpm (92.9 gpm)
Max. Size Solids..................4.8 mm (3/16”)
1Displacement per stroke was calculated at
4.8 bar (70 psig) air inlet pressure against
a 2.1 bar (30 psig) head pressure.
Example: To pump 288 lpm (76 gpm)
against a discharge head of 2.1 bar (30
psig) requires 6.9 bar (100 psig) and 158
Nm³/hr air consumption.
Caution: Do not exceed 8.6 bar (125 psig)
air supply pressure.
WILDEN PUMP & ENGINEERING, LLC 6 WIL-10160-E-10

Suction-lift curves are calibrated for pumps operating
at 305 m (1,000') above sea level. This chart is meant
to be a guide only.There are many variables which can
affect your pump’s operating characteristics.
The number of intake and discharge elbows, viscosity
of pumping fluid, elevation (atmospheric pressure) and
pipe friction loss all affect the amount of suction lift
your pump will attain.
P4 PLASTIC SUCTION-
LIFT CAPABILITY
SUCTION-LIFT CURVES
WIL-10160-E-10 7 WILDEN PUMP & ENGINEERING, LLC

The P4 pump has a 38 mm (1-1/2") inlet and 38 mm (1-1/2")
outlet and is designed for flows to 354 lpm (94 gpm). The
P4 Plastic pump is manufactured with wetted parts of pure,
unpigmented, PTFE or polypropylene. The P4 Plastic is
constructed with a polypropylene center block. A variety of
diaphragms and O-rings are available to satisfy temperature,
chemical compatibility, abrasion and flex concerns.
The suction pipe size should be at least 38 mm (1-1/2")
diameter or larger if highly viscous material is being pumped.
The suction hose must be non-collapsible, reinforced type
as the P4 is capable of pulling a high vacuum. Discharge
piping should be at least 38 mm (1-1/2"); larger diameter can
be used to reduce friction losses. It is critical that all fittings
and connections are airtight or a reduction or loss of pump
suction capability will result.
For P4 Plastic models, Wilden offers 150 lb standard and
metric flanges. The following details should be noted when
mating these to pipe works:
• A 60–80 shore gasket that covers the entire ßflange face
should be used.
• The gasket should be between 1.91 mm (0.075") and 4.45
mm (0.175") thickness.
• Mating flanges with flat as opposed to raised surfaces
should be used for proper mechanical sealing.
• The flanges should be tightened to a minimum of 6.8
N•m (5 ft-lb) but no more than 13.5 N•m (10 ft-lb).
INSTALLATION: Months of careful planning, study,
and selection efforts can result in unsatisfactory pump
performance if installation details are left to chance.
Premature failure and long term dissatisfaction can be
avoided if reasonable care is exercised throughout the
installation process.
LOCATION: Noise, safety, and other logistical factors usually
dictate where equipment be situated on the production
floor. Multiple installations with conflicting requirements
can result in congestion of utility areas, leaving few choices
for additional pumps.
Within the framework of these and other existing conditions,
every pump should be located in such a way that five
key factors are balanced against each other to maximum
advantage.
ACCESS: First of all, the location should be accessible. If
it’s easy to reach the pump, maintenance personnel will
have an easier time carrying out routine inspections and
adjustments. Should major repairs become necessary, ease
of access can play a key role in speeding the repair process
and reducing total downtime.
AIR SUPPLY: Every pump location should have an air line
large enough to supply the volume of air necessary to
achieve the desired pumping rate (see Section 5). Use air
pressure up to a maximum of 8.6 bar (125 psig) depending
on pumping requirements.
For best results, the pumps should use a 5µ micron air
filter, needle valve and regulator. The use of an air filter
before the pump will insure that the majority of any pipeline
contaminants will be eliminated.
SOLENOID OPERATION: When operation is controlled by a
solenoid valve in the air line, three-way valves should be
used, thus allowing trapped air to bleed off and improving
pump performance. Pumping volume can be set by
counting the number of strokes per minute and multiplying
by displacement per stroke.
Sound levels are reduced below OSHA specifications using
the standard Wilden muffler element. Other mufflers can be
used but usually reduce pump performance.
ELEVATION: Selecting a site that is well within the pump’s
dynamic lift capability will assure that loss-of-prime troubles
will be eliminated. In addition, pump efficiency can be
adversely affected if proper attention is not given to site
location.
PIPING: Final determination of the pump site should not be
made until the piping problems of each possible location
have been evaluated. The impact of current and future
installations should be considered ahead of time to make
sure that inadvertent restrictions are not created for any
remaining sites.
The best choice possible will be a site involving the shortest
and straightest hook-up of suction and discharge piping.
Unnecessary elbows, bends, and fittings should be avoided.
Pipe sizes should be selected so as to keep friction losses
within practical limits. All piping should be supported
independently of the pump. In addition, the piping should
be aligned so as to avoid placing stresses on the pump
fittings.
Flexible hose can be installed to aid in absorbing the forces
created by the natural reciprocating action of the pump. If the
pump is to be bolted down to a solid location, a mounting
pad placed between the pump and the foundation will assist
in minimizing pump vibration. Flexible connections between
the pump and rigid piping will also assist in minimizing
pump vibration. If quick-closing valves are installed at any
point in the discharge system, or if pulsation within a system
becomes a problem, a surge suppressor should be installed
to protect the pump, piping and gauges from surges and
water hammer.
When pumps are installed in applications involving flooded
suction or suction head pressures, a gate valve should be
installed in the suction line to permit closing of the line for
pump service.
For P4 Plastic models, a non-raised surfaced-flange adapter
should be utilized when mating to the pump’s inlet and
discharge manifolds for proper sealing.
If the pump is to be used in a self-priming application, be
sure that all connections are airtight and that the suction lift
is within the model’s ability. Note: Materials of construction
and elastomer material have an effect on suction lift
parameters. Please consult Wilden distributors for specifics.
Pumps in service with a positive suction head are most
efficient when inlet pressure is limited to 0.5–0.7 bar (7–10
psig). Premature diaphragm failure may occur if positive
suction is 10 psig and higher.
THE MODEL P4 CHAMP WILL PASS 0.5 MM (3/16") SOLIDS.
WHENEVERTHE POSSIBILITY EXISTSTHAT LARGER SOLID
OBJECTS MAY BE SUCKED INTO THE PUMP, A STRAINER
SHOULD BE USED ONTHE SUCTION LINE.
CAUTION: DO NOT EXCEED 8.6 BAR (125 PSIG) AIR SUPPLY
PRESSURE.
P4 PUMPS CANNOT BE SUBMERGED. FOR SUBMERGED
APPLICATIONS, USE A WILDEN T4 PUMP.
WILDEN PUMP & ENGINEERING, LLC 8 WIL-10160-E-10
Section 6
SUGGESTED INSTALLATION

NOTE: In the event of a power failure, the shut-off valve
should be closed, if the restarting of the pump is not
desirable once power is regained.
AIR-OPERATED PUMPS: To stop the pump from operating
in an emergency situation, simply close the “shut-off”
valve (user-supplied) installed in the air supply line. A
properly functioning valve will stop the air supply to
the pump, therefore stopping output. This shut-off valve
should be located far enough away from the pumping
equipment such that it can be reached safely in an
emergency situation.
SUGGESTED INSTALLATION
WIL-10160-E-10 9 WILDEN PUMP & ENGINEERING, LLC

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 SUGGESTED
INSTALLATION).
3. Check for extreme air leakage (blow by) that 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 that 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 that 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,
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 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 P4 pump is pre-lubricated, and does
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 DISASSEMBLY / REASSEMBLY 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 P4 pump runs 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 abrasiveness 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. 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.
TROUBLESHOOTING
WILDEN PUMP & ENGINEERING, LLC 10 WIL-10160-E-10
SUGGESTED OPERATION & MAINTENANCE

Step 2. Figure 2
Utilizing a 1/2" wrench, remove the
two small clamp bands that fasten
the discharge manifold to the liquid
chambers.
Step 3. Figure 3
Remove the discharge manifold to
expose the valve balls and seats.
Inspect ball cage area of manifold
for excessive wear or damage.
Step 1. Figure 1
Before starting disassembly, mark
a line from each liquid chamber to
its corresponding air chamber. This
line will assist in proper alignment
during reassembly.
Tools Required:
• 1/2" Wrench
• Adjustable Wrench
• Vise equipped with
soft jaws (such as
plywood, plastic
or other suitable
material)
CAUTION: Before any maintenance or repair is attempted, the compressed air line
to the pump should be disconnected and all air pressure allowed to bleed from the
pump. Disconnect all intake, discharge, and air lines. Drain the pump by turning it
upside down and allowing any fluid to flow into a suitable container. Be aware of
any hazardous effects of contact with your process fluid.
The Wilden P4 has a 38 mm (1-1/2") inlet and outlet and is designed for flows up
to 354 lpm (94 gpm). Its air distribution system is based on a revolutionary design
which increases reliability and performance. The model P4 is available in injection
molded polypropylene, PTFE PFA and PVDF wetted parts.
NOTE:The model used for these instructions incorporates rubber diaphragms, balls,
and seats. Models with PTFE diaphragms, balls and seats are the same except where
noted.
TK TK
WIL-10160-E-10 11 WILDEN PUMP & ENGINEERING, LLC
Section 7
PUMP DISASSEMBLY

Step 6. Figure 6
Lift intake manifold from liquid
chambers and center section to
expose intake valve balls and seats.
Inspect ball cage area of liquid
chambers for excessive wear or
damage.
Step 7. Figure 7
Remove valve seats and valve balls
for inspection. Replace if necessary.
Step 8. Figure 8
Remove small manifold clamp
bands to inspect manifold O-rings.
Step 4. Figure 4
Remove the discharge valve balls and seats from
the liquid chambers and inspect for nicks, gouges,
chemical attack or abrasive wear. Replace worn parts
with genuine Wilden parts for reliable performance.
Step 5. Figure 5
Remove the two small clamp bands which fasten the
intake manifold to the liquid chambers.
WILDEN PUMP & ENGINEERING, LLC 12 WIL-10160-E-10
PUMP DISASSEMBLY

Step 9. Figure 9
Remove one set of large clamp
bands which secure one liquid
chamber to the center section.
Step 10. Figure 10
Lift liquid chamber away from
center section to expose diaphragm
and outer piston.
Step 11. Figure 11
Using an adjustable wrench, or by
rotating the diaphragm by hand,
remove the diaphragm assembly.
Step 12. Figure 12
NOTE: Due to varying torque values, one of the following two situations
may occur: 1) The outer piston, diaphragm and inner piston remain
attached to the shaft and the entire assembly can be removed from the
center section (Figure 12). 2)The outer piston, diaphragm and inner piston
separate from the shaft which remains connected to the opposite side
diaphragm assembly (Figure 13). Repeat disassembly instructions for the
opposite liquid chamber. Inspect diaphragm assembly and shaft for signs
of wear or chemical attack. Replace all worn parts with genuine Wilden
parts for reliable performance.
Step 13. Figure 14
To remove diaphragm assembly
from shaft, secure shaft with soft
jaws (a vise fitted with plywood,
plastic or other suitable material) to
ensure shaft is not nicked, scratched
or gouged. Using an adjustable
wrench, remove diaphragm
assembly from shaft.
Figure 13
WIL-10160-E-10 13 WILDEN PUMP & ENGINEERING, LLC
PUMP DISASSEMBLY

Step 2. Figure 2
Remove muffler plate and air valve
bolts from air valve assembly
exposing muffler gasket for
inspection. Replace if necessary.
Step 3. Figure 3
Lift away air valve assembly
and remove air valve gasket for
inspection. Replace if necessary.
Step 4. Figure 4
Remove air valve end cap to expose
air valve spool by simply lifting up
on end cap once air valve bolts are
removed.
Tools Required:
• 3/16" Hex-Head
Wrench
• 1/4" Hex-Head Wrench
• Snap-Ring Pliers
• O-Ring Pick
AIR VALVE DISASSEMBLY:
CAUTION: Before any maintenance or repair is attempted, the compressed air line
to the pump should be disconnected and all air pressure allowed to bleed from the
pump. Disconnect all intake, discharge, and air lines. Drain the pump by turning it
upside down and allowing any fluid to flow into a suitable container. Be aware of
hazardous effects of contact with your process fluid.
The Wilden P4 plastic pump utilizes a revolutionary Pro-Flo®air distribution system.
A 13 mm (1/2") air inlet connects the air supply to the center section. Proprietary
composite seals reduce the coefficient of friction and allow the P4 to run lube-free.
The Pro-Flo®air distribution system is designed to perform in on/off, non-freezing,
non-stalling, tough duty applications.
Step 1. Figure 1
Loosen the air valve bolts utilizing
a 3/16" hex-head wrench and then
remove muffler plate screws.
WILDEN PUMP & ENGINEERING, LLC 14 WIL-10160-E-10
Section 8B
PRO-FLO
® AIR DISTRIBUTION SYSTEM (ADS) DISASSEMBLY

Step 8. Figure 8
Remove pilot spool bushing from
center block.
Step 9. Figure 9
With O-ring pick, gently remove the o-ring
from the opposite side of the “center
hole” cut on the spool. Gently remove
the pilot spool from sleeve and inspect
for nicks or gouges and other signs of
wear. Replace pilot sleeve assembly or
outer sleeve O-rings if necessary. During
re-assembly never insert the pilot spool
into the sleeve with the “center cut” side
first, this end incorporates the urethane
o-ring and will be damaged as it slides
over the ports cut in the sleeve.
NOTE: Seals should not be removed
from pilot spool. Seals are not sold
separately.
Step 10. Figure 10
Check center block Glyd™ rings for
signs of wear. If necessary, remove
Glyd™ rings with O-ring pick and
replace.
NOTE: Threaded sleeves (see A —
Figure 10) are removable and can be
replaced if necessary. Sleeves can
be press fit by hand.
Step 5. Figure 5
Remove air valve spool from air valve
body by threading one air valve bolt
into the end of the spool and gently
sliding the spool out of the air valve
body. Inspect seals for signs of wear and
replace entire assembly if necessary.
Use caution when handling air valve
spool to prevent damaging seals.
NOTE: Seals should not be remove
from assembly. Seals are not sold
separately.
Step 6. Figure 6
Remove pilot spool retaining snap
ring on both sides of center section
with snap-ring pliers.
Step 7. Figure 7
Remove air chamber bolts with 1/4"
hex-head wrench.
A
WIL-10160-E-10 15 WILDEN PUMP & ENGINEERING, LLC
PRO-FLO
® AIR DISTRIBUTION SYSTEM (ADS) DISASSEMBLY

REASSEMBLY:
Upon performing applicable maintenance to the air
distribution system, the pump can now be reassembled.
Please refer to the disassembly instructions for photos
and parts placement. To reassemble the pump, follow
the disassembly instructions in reverse order. The air
distribution system needs to be assembled first, then
the diaphragms and finally the wetted path. Please find
the applicable torque specifications on this page. The
following tips will assist in the assembly process.
• Lubricate air valve bore, center section shaft and pilot
spool bore with NLGI grade 2 white EP bearing grease
or equivalent.
• Clean the inside of the center section shaft bushing to
ensure no damage is done to new Glyd™ ring seals.
• A small amount of NLGI grade 2 white EP bearing
grease can be applied to the muffler and air valve
gaskets to locate gaskets during assembly.
• Make sure that the exhaust port on the muffler plate is
centered between the two exhaust ports on the center
section.
• Stainless bolts should be lubed to reduce the possibility
of seizing during tightening.
• Use a mallet to tamp lightly on the large clamp bands
to seat the diaphragm before tightening.
GLYD™ RING INSTALLATION:
PRE-INSTALLATION
• Once all of the old seals have been removed, the inside
of the bushing should be cleaned to ensure no debris
is left that may cause premature damage to the new
seals.
INSTALLATION
The following tools can be used to aid in the installation
of the new seals:
Needle-Nose Pliers
Phillips Screwdriver
ElectricalTape
• Wrap electrical tape around each leg of the needle-
nose pliers (heat shrink tubing may also be used). This
is done to prevent damaging the inside surface of the
new seal.
• With a new seal in hand, place the two legs of the
needle-nose pliers inside the seal ring. (See Figure A.)
• Open the pliers as wide as the seal diameter will allow,
then with two fingers pull down on the top portion of
the seal to form a kidney shape. (See Figure B.)
• Lightly clamp the pliers together to hold the seal into
the kidney shape. Be sure to pull the seal into as tight
of a kidney shape as possible, this will allow the seal to
travel down the bushing bore easier.
• With the seal clamped in the pliers, insert the seal into
the bushing bore and position the bottom of the seal
into the correct groove. Once the bottom of the seal is
seated in the groove, release the clamp pressure on the
pliers. This will allow the seal to partially snap back to
its original shape.
• After the pliers are removed, you will notice a slight
bump in the seal shape. Before the seal can be properly
resized, the bump in the seal should be removed as
much as possible. This can be done with either the
Phillips screwdriver or your finger. With either the side
of the screwdriver or your finger, apply light pressure
to the peak of the bump. This pressure will cause the
bump to be almost completely eliminated.
• Lubricate the edge of the shaft with NLGI grade 2 white
EP bearing grease.
• Slowly insert the center shaft with a rotating motion.
This will complete the resizing of the seal.
• Perform these steps for the remaining seal.
MAXIMUM TORQUE SPECIFICATIONS
Description of Part Plastic Pumps
Air Valve 5.1 N•m (45 in-lb)
Outer Piston 47.5 N•m (35 ft-lb)
Small Clamp Band 9.6 N•m (85 in-lb)
Large Clamp Band (Rubber-Fitted) 18.6 N•m (165 in-lb)
Large Clamp Band (PTFE-Fitted) 18.6 N•m (165 in-lb)
Air Chamber Screws (HSFHS 3/8"-16) 47.5 N•m (35 ft-lb)
NEEDLE-NOSE
PLIERS
GLYD™ RING
TAPE
Figure A Figure B
WILDEN PUMP & ENGINEERING, LLC 16 WIL-10160-E-10
Section 8C
REASSEMBLY HINTS & TIPS

Step 7. Figure 7
Gently apply pressure to gasket to ensure the adhesive
maintains a positive seal to stay in place during pump
assembly.
Step 6. Figure 6
Center the gasket so that it evenly covers the O-ring
and seat areas.
Step 4. Figure 4
Carefully remove the protective covering from the back
of the PTFE gasket attached to tape.
Step 5. Figure 5
Install the valve ball, valve seat and O-ring.
Step 2. Figure 2
Starting at any point, place the PTFE
tape in the center of the diaphragm
bead groove on the liquid chamber
and press lightly on the tape to
ensure that the adhesive holds it
in place during assembly. Do not
stretch the tape during placement in
center of diaphragm bead groove.
Step 3. Figure 3
The ends of the tape should overlap
approximately 13 mm (1/2").
Proceed to install the PTFE tape on
the remaining liquid chamber.
Step 1. Figure 1
Gently remove the adhesive
covering from the back of the PTFE
tape. Ensure that the adhesive strip
remains attached to the PTFE tape.
Only P4 PVDF pumps come standard with expanded
PTFE Gasket Kits (P/N 04-9501-99). Carefully prepare
sealing surfaces by removing all debris and foreign
matter from diaphragm bead and all mating surfaces.
If necessary, smooth or deburr all sealing surfaces.
Mating surfaces must be properly aligned in order to
ensure positive sealing characteristics.
WIL-10160-E-10 17 WILDEN PUMP & ENGINEERING, LLC
Section 8D
GASKET KIT INSTALLATION

FULL-STROKE PTFE-FITTED
WILDEN PUMP & ENGINEERING, LLC 18 WIL-10160-E-10
P4 PLASTIC FULL-STROKE/3-PIECE CENTER-SECTION EXPLODED VIEW
Section 8
EXPLODED VIEW AND PART LISTINGS