Wilden PROFLO P.025 Instruction Manual

EOM
ENGINEERING OPERATION
& MAINTENANCE
P.025 Clamped
Metal Pump
WIL-10080-E-06
Where InnovationFlows

WIL-10080-E-06 Wilden®
2
Contents
Section 1: Precautions - Read First! 4
Section 2: Wilden Pump Designation System 5
Section 3: How It Work—Pump & Air Distribution System 6
Section 4: Dimensional Drawings 7
Section 5: Performance 8
P.025 Metal- F it ted 8
P.025 Rubber - F i tted 8
P.025 TPE-Fi t te d 9
Suction- L i ft Cur ves 10
Section 6: Suggested Installation, Operation, 11
Maintenance and Troubleshooting
Section 7: Disassembly / Reassembly 14
Pump D i sassemb ly 14
Air Valve / Center Section Disass e m b ly 17
Reassembly H in ts & T i ps 19
Section 8: Exploded View and Parts List 21
P.025 Metal R ubber/T P E - F itted. 21
P.025 Metal PTFE-F i tted. 23
Section 9: Elastomer Options 25

WIL-10080-E-06 Wilden®
3
Copyright
Copyright 2018 PSG®, a Dover Company. All rights reserved.
PSG reserves the right to modify the information and illustrations in this document without prior notice. The
product described in this document is furnished under a license agreement or nondisclosure agreement. No
part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or any
means electronic or mechanical, including photocopying and recording, without the written permission of PSG,
a Dover Company, except as described by the terms of those agreements.
This is a non-contractual document. 01-2019.
Trademarks
PSG and the PSG logo are registered trademarks of PSG. Wilden® is a registered trademark of PSG
California LLC. Pro-Flo® SHIFT and Pro-Flo® are registered trademarks of PSG California LLC. Wil-Flex® is a
trademark of PSG California LLC. Saniflex™ is a trademark of PSG California LLC.
All trademarks, names, logos and service marks (collectively "trademarks") in this document are registered
and unregistered trademarks of their respective owners. Nothing contained in this document should be
construed as granting any license or right to use any trademark without the prior written permission of the
trademark owner.
Warranty
Each and every product manufactured by Wilden is built to meet the highest standards of quality. Every pump
is functionally tested to insure integrity of operation. Wilden warrants that pumps, accessories and parts
manufactured or supplied by it to be free from defects in material and workmanship for a period of five (5)
years from date of installation or six (6) years from date of manufacture, whichever comes first.
For more information, and to register your Wilden pump for warranty, please visit
https://www.psgdover.com/wilden/support/warranty-registration.
Certifications

WIL-10080-E-06 Wilden®
4
Precautions - Read First!
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
PTFE 1
4°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
14°C to 149°C (40°F to 300°F) - 13 mm (1/2") and 25 mm (1") models only.
NOTE: Not all materials are available for all models. See "Wilden Pump Designation System
on page 5 for material options for your pump.
CAUTION: When choosing pump materials, be sure to check the
temperature limits for all wetted components.
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.
WARNING: Always wear safety glasses when operating pump.
If diaphragm rupture occurs, material being pumped may be forced
out air exhaust.
CAUTION: Prevent static sparking —If static sparking occurs, fire or
explosion could result. Pump, valves, and containers must be
properly grounded when handling flammable fluids and whenever
discharge of static electricity is a hazard.
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 pipe line debris is clear. Use an in-line air
filter. A 5µµ(micron) air filter is recommended.
CAUTION: Tighten clamp bands and manifold
bolts prior to installation. Fittings may loosen
during transportation.
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.
NOTE: Verify the chemical compatibility of the process
and cleaning fluid to the pump's component materials in
the Chemical Resistance Guide.
NOTE: The P .025 pump is not submersible.
CAUTION: Pump performance will be seriously
hampered if pump is installed upside down.
Section 1

WIL-10080-E-06 Wilden®
5
LEGEND
MATERIAL CODES
MODEL
P.025 = PRO-FLO
®
WETTEDPATH
A = ALUMINUM
S = STAINLESS STEEL
OUTERPISTON
A = ALUMINUM
M = MILD STEEL
S = STAINLESS STEEL
Z = NO OUTER PISTON
CENTER SECTION
LL = ACETAL
PP = POLYPROPYLENE
AIR VALVE
L = ACETAL
P = POLYPROPYLENE
DIAPHRAGMS
BNS = BUNA-N (Red Dot)
TEL = PTFE w/EPDM BACKUP
O-RING, IPD (White)
TNL = PTFE W/NEOPRENE
BACKUP O-RING,
IPD (White)
WFS = WIL-FLEX™ [Santoprene
®
(Three Black Dots)]
VALVE BALLS
TF = PTFE (White)
VALVE SEATS
A = ALUMINUM
H = ALLOY C
S = STAINLESS STEEL
VALVE SEAT O-RINGS
BN = BUNA-N
TF = PTFE (White)
TV = PTFE ENCAP. FKM
WF = WIL-FLEX™ (Santoprene®)
MANIFOLD O-RINGS
BN = BUNA-N (Red Dot)
TF = PTFE (White)
SPECIALTY CODES
0502 PFA coated hardware
0512 Adapter block, no muffler, Pro ‑ Flo ® ,
center section
0560 Split manifold
0562 Split manifold, BSPT
0670 Inlet manifold, dual ported, NPT
0671 Inlet manifold, dual ported, BSPT
NOTE: Most elastomeric materials use colored dots for identification.
NOTE: Not all models are available with all material options.
.
P.025 METAL
6 mm (1/4") Pump
Maximum Flow Rate:
18.9 lpm (5.0 gpm
P.025
/
X
X
X
X
X
/
XXX
/
XX
/
X
XX
/
XXXX
MODEL
O-RINGS
VALVE SEAT
SPECIALTY CODE
VALVE BALLS
(if applicable)
DIAPHRAGMS
AIR VALVE
CENTER SECTION
OUTER PISTON
WETTED PATH
Section 2
WILDEN PUMP DESIGNATION SYSTEM

WIL-10080-E-06 Wilden®
6
The Wilden diaphragm pump is an air-operated, placement, self-priming pump. These drawings show the flow pattern
through the pump upon its initial stroke. It is assumed the pump has no fluid in it prior to its initial stroke.
FIGURE1 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, balancing the
load and removing 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 mani-
fold 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 thestroke,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.
HOW IT WORKS —AIR DISTRIBUTION SYSTEM
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.
Section 3
HOW IT WORKS —PUMP

WIL-10080-E-06 Wilden®
7
P.025 Metal
DIMENSIONS
ITEM
METRIC (mm)
STANDARD (inch)
A
165
6.5
B
84
3.3
C
147
5.8
D
135
5.3
E
13
0.5
F
114
4.5
G
91
3.6
H
61
2.4
J
8
0.3
K
71
2.8
L
46
1.8
LW0348 REV. B.
DIMENSIONAL DRAWING
Section 4

WIL-10080-E-06 Wilden®
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PERFORMANCE
P.025 METAL
RUBBER-FITTED
ShipWeight...........Aluminum 1.8 kg (4 lb)
Stainless Steel 4.0 kg (8.9 lb)
Hastelloy
®
4.3 kg (9.5 lb)
Air Inlet.................................3.2 mm (1/8")
Inlet.................................... 6.4 mm (1/4")
Outlet ...................................6.4 mm (1/4")
Suction Lift................... 3.3 m Dry (10 ' 8 " )
9.3 m Wet (30'6")
Disp.PerStroke
1
............ 0.02 L (0.005 gal)
Max.FlowRate...........18.91 lpm (5 gpm)
Max. Size Solids................. 0.4 mm (1/64")
1
Displacement per stroke was calculated
at 70 psig (4.8 bar) air inlet pressure
against a 30 psig (2 bar) head pressure.
Example: To pump 7.6 lpm (2 gpm)
against a discharge pressure head of
40 psig (2.8 bar) requires 4.1 bar (61 psig)
and 1.2 Nm
3
/h (0.7 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.
P.025 METAL
TPE-FITTED
ShipWeight...........Aluminum1.8 kg (4 lb)
Stainless Steel 4.0 kg (8.9 lb)
Hastelloy
®
4.3 kg (9.5 lb)
Air Inlet.................................3.2 mm (1/8")
Inlet.................................... 6.4 mm (1/4")
Outlet ...................................6.4 mm (1/4")
Suction Lift................... 3.3 m Dry (10 ' 8 " )
9.3 m Wet (30'6")
Disp.PerStroke
1
............ 0.02 L (0.005 gal)
Max.FlowRate...........18.91 lpm (5 gpm)
Max. Size Solids.................0.4 mm (1/64")
1
Displacement per stroke was calculated
at 70 psig (4.8 bar) air inlet pressure
against a 30 psig (2 bar) head pressure.
Example: To pump 7.6 lpm (2 gpm)
against a discharge pressure head of
40 psig (2.8 bar) requires 4.0 bar (59 psig)
and 1.1 Nm
3
/h (0.7 scfm) air consumption.
(See dot on chart.).
Caution: Do not exceed 8.6 bar
(125 psig) air supply pressure.
Section 5
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.

WIL-10080-E-06 Wilden®
9
PERFORMANCE
P.025 METAL
PTFE-FITTED
ShipWeight.............Aluminum 1.8 kg (4 lb)
Stainless Steel 4.0 kg (8.9 lb)
Hastelloy
®
4.3 kg (9.5 lb)
Air Inlet................................... 3.2 mm (1/8")
Inlet...................................... 6.4 mm (1/4")
Outlet ..................................... 6.4 mm (1/4")
Suction Lift............................4 m Dry (13 ' )
9.5 m Wet (31'2")
Disp.PerStroke
1
...............0.02 L (0.005 gal)
Max.FlowRate...............18.9 lpm (5 gpm)
Max. Size Solids....................0.4 mm (1/64")
1
Displacement per stroke was calculated
at 70 psig (4.8 bar) air inlet pressure against
a 30 psig (2 bar) head pressure.
Example: To pump 7.6 lpm (2 gpm)
against a discharge pressure head of 2.8 bar
(40 psig) requires 4.0 bar (58 psig) and
1.0 Nm
3
/h (0.6 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.

WIL-10080-E-06 Wilden®
10
SUCTION LIFT CURVES
P.025 METAL
SUCTION - LIFT
CAPABILITY
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 that 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.

WIL-10080-E-06 Wilden®
11
Suggested Installation, Operation, Maintenance and Troubleshooting
The Pro-Flo model P.025 has a 6 mm (1⁄4") inlet and 6 mm (1/4") outlet and
is designed for flows to 18 .9 lpm (5 gpm). The P.025 metal pump is
manufactured with wetted parts of aluminum Hastelloy®and stainless steel.
The center section of the P.025 metal is constructed of virgin acetal or
polypropylene. 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 6 mm (1/4") diameter or larger if
highly viscous material is being pumped. The suction hose must be non-
collapsible, reinforced type as the P .025 is capable of pulling a high vacuum.
Discharge piping should be at least 6 mm (1/4"); 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.
CAUTION: All fittings and connections must be airtight. Otherwise,
pump suction capability will be reduced or lost.
Months of careful planning, study and selection efforts can result in
unsatisfactory pump performance if installation details are left to chance.
You can avoid premature failure and long-term dissatisfaction by exercising
reasonable care throughout the installation process.
Location
Noise, safety and other logistical factors usually dictate where equipment
will 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, locate every
pump in such a way that the following six key factors are balanced against
each other to maximum advantage:
• Access: First, the location should be accessible. If it’s easy to reach the
pump, maintenance personnel will be able to perform routine inspections
and adjustments more easily. If 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.
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 ensure
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. This valve allows trapped
air between the valve and the pump to bleed off, which improves pump
performance. You can estimate pumping volume by counting the number
of strokes per minute, and then multiplying that figure by the displacement
per stroke.
• Muffler: Using the standard Wilden muffler, sound levels are reduced
below OSHA specifications. You can use other mufflers to reduce sound
levels farther, but they usually reduce pump performance .
• Elevation: Selecting a site that is well within the pump’s dynamic lift
capability will assure that loss-of-prime issues 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 challenges 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 to keep friction losses within practical limits. All piping
should be supported independently of the pump. In addition, the
piping should be aligned to avoid placing stress 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 (SD Equalizer)
should be installed to protect the pump, piping and gauges from
surges and water hammer.
If the pump is to be used in a self-priming application, make 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 refer to
"Performance " on page 8 for specifics.
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.
The P.025 cannot be used in submersible applications.
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 0.7 bar (10 psig) and higher.
The model P.025 will pass 0.4 mm (1/64") solids. Whenever the
possibility exists that larger solid objects may be sucked into the pump, a
strainer should be used on the suction line.
NOTE: Pro-Flo®and Accu-Flo™ pumps do not have a
single-point exhaust option and are not submersible.
CAUTION: All Wilden pumps are capable of passing solids.
A strainer should be used on the pump intake to ensure that
the pump's rated solids capacity is not exceeded.
CAUTION: Do not exceed 8.6 bar (125 psig) air
supply pressure.
Section 6

WIL-10080-E-06 Wilden®
12
Suggested Installation, Operation, Maintenance and Troubleshooting
NOTE: In the event of a power failure, close the shut-
off valveif youdo not want the pump to restart when the
power returns.
Air-Operated Pumps: To stop the pump from operating in an
emergency situation, simply closetheshut-offvalve(user-
supplied) installed in the air supply line. A properly functioning
valve will stop the air supplyto 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.
NOTE: Wilden 6 mm (1/4") metal pumps come standard
side-ported with 2 NPT or BSP pipe plugs for side inlet
and discharge porting. Center, top and bottom inlet and
discharge porting are optional. Simply drill flat areas
provided with a 7/16" drill bit for NPT or 11 mm drill bit
for BSP and tap with an NTP or BSP tap as needed.
NOTE: Wilden offers drum pump kits for the Metal
P.025/A.025 pump (bung base and pick-up tube) for
convenient drum pumping (P/N 50-9290-20/23/55).
Operation
The P.025 are pre-lubricated and do not require in- linelubrication.
Additionallubrication willnot damage the pump.
However, if the pump is heavilylubricated by an external source,
the pump’s internal lubrication maybe washed away. If the pump
is then moved to a nonlubricated location, it may need to be
disassembled and re-lubricated as described in "Disassembly/
Reassembly" on page 14.
Pump discharge rate can be controlled bylimiting the volume and/or
pressure of the air supplyto the pump. An air regulator isused to
regulate air pressure. A needle valve is used to regulate volume.
Pump discharge rate also can 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 "Performance " on page 8.) 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 willnot occur. The pump has reached a “deadhead” situation
and can be restarted by reducing the fluid discharge pressure or
increasingthe air inlet pressure. Wilden Pro-Flo pumps run solelyon
compressed air and do not generate heat.
Therefore, your process fluid temperature will not be affected.
Maintenance and Inspections
Because each application isunique,maintenance schedules maybe
different for every pump. Frequency of use, line pressure, viscosity
and abrasiveness of process fluid allaffect the parts lifeof a Wilden
pump. Periodic inspectionshave been found to offer the best means
for preventingunscheduledpump downtime. Personnel familiar with
the pump’s construction and service should be informed of any
abnormalitiesthat are detected during operation.

WIL-10080-E-06 Wilden®
13
Suggested Installation, Operation, Maintenance and Troubleshooting
Troubleshooting
Pump will not run or runs slowly.
1. Remove plug from pilot spool exhaust.
2. Ensure that the air inlet pressure is at least 0.4 bar (5 psig)
abovestartuppressure and that thedifferentialpressure
(the difference between air inletand liquiddischarge
pressures) is not lessthan 0.7 bar (10 psig).
3. Check air inlet filter for debris (see "Suggested
Installation, Operation, Maintenance and
Troubleshooting" on page 11).
4. Check for extreme air leakage(blow by) that would
indicate worn seals/boresin the air valve, pilot spool and
main shaft.
5. Disassemble the pump and check for obstructions in the air
passageways or objectsthat would obstruct the movement
of internal parts.
6. Check for sticking ball check valves.
a. If material being pumped is not compatiblewith pump
elastomers, swelling may occur. Replace ball check
valves and seals with proper elastomers.
b. Also, asthe check valve ballswear out, they become
smaller and can become stuck in the seats. In this case,
replace ballsand seats.
7. Check for any broken inner piston that would cause
the air valve spool to be unable to shift.
Pump runs, but little or no product flows.
1. Check for pump cavitation. Slow pump speed down to
allow thick material to flow into liquid chambers.
2. Verifythat vacuum required to lift liquidis not greater than the
vapor pressure of the material being pumped (cavitation).
3. Check for sticking ball check valves.
a. If material being pumped is not compatiblewith pump
elastomers, swelling may occur. Replace ball check
valves and seals with proper elastomers.
b. Also, as the check valve balls wear out, they become
smaller and can become stuckin the seats. In this
case, replace ballsand seats.
Pump air valve freezes.
1. Check for excessive moisture in the compressed air.
a. Either installa dryer or a hot air generator for
compressed air.
b. Alternatively, you may use coalescing filter to remove
the water from the compressed air in some applications.
Air bubbles in pump discharge.
1. Check for a ruptured diaphragm.
2. Check tightness of outer pistons(see
Disassembly/Reassembly on page 14).
3. Check tightness of fasteners and integrityof O-rings
and seals, especiallyat intake manifold.
4. Ensure pipe connections are airtight.
Product comes out air exhaust.
1. Check for a diaphragm rupture.
2. Check the tightnessof the outer pistonsto the shaft.

WIL-10080-E-06 Wilden®
14
Disassembly / Reassembly
Pump Disassembly
Tools Required:
• 3/16" Hex-Head Wrench
• 7/16" Wrench or Socket for
Rubber-Fitted
• 5/16" Wrench or Socket
• 3/8" Wrench O-Ring Pick
• 3/16" Rod or Equivalent)
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.
Wetted flushing of parts may be required prior to handling.
The Wilden model P .025 is an air-operated, double-diaphragm pump with all
wetted parts of aluminum, stainless steel or Hastelloy
®
. The single-piece center
section, consisting of center block and air chambers, is molded from acetal or
polypropylene. The air valve is manufactured of acetal or polypropylene.
All O-rings used in the pump are of special materials and should only be
replaced with factory-supplied parts.
To expedite parts ordering, please find an exploded view of the P .025 model at
the back of this manual.
PLEASE read all directions before starting disassembly.
NOTE: Replace worn parts with genuine Wilden parts for reliable performance.
Step 1
Before actual disassembly is started, turn
pump upside down and drain all liquid
trapped in the pump into a suitable
container. Be sure to use proper caution if
liquid is corrosive or toxic. Mark each liquid
chamber to its respective air chamber for
easy alignment during reassembly.
Step 2
Using a 3/16" hex-head wrench, loosen
the four manifold bolts. Remove the top
and bottom manifolds .
Step 3
Inspect both manifolds, manifold O-rings,
and valve balls. If swelling, cracking or
other damage is apparent, these parts
must be replaced with genuine Wilden
parts .
Section 7

WIL-10080-E-06 Wilden®
15
Disassembly / Reassembly
Step 4
NOTE: Top valve seats of
aluminum P .025 pumps are
cast in the liquid chamber.
Step 4a
To remove top and bottom valve
seats, on stainless steel or Hastelloy®
pumps, use an O-ring pick and pull
seats out from top to bottom or use
3/16" rod and push seats through.
Step 5
Remove bottom manifold. Inspect balls and
seats for abrasion. Inspect seat O-rings and
manifold O-rings for swelling, cracking, or
other damage. These parts should be
replaced if damage is observed.
NOTE: Aluminum pumps require
two (2) O-rings per valve seat.
Step 6
Loosen clamp band with 5/16" socket and
3/8" wrench. Remove screw and nut.
Step 7
After clamp bands are removed, pull
chambers away from center section.
Step 8
Remove diaphragm by turning in
counterclockwise direction.
NOTE: PTFE-fitted pumps (shown)
utilize a Neoprene back-up O-ring.
Rubber or TPE-fitted pumps do not.
(See Step 10 for details .).

WIL-10080-E-06 Wilden®
16
Disassembly / Reassembly
Step 9
Pull off PTFE diaphragm and O-ring.
Twist off remaining diaphragm in
counterclockwise direction. Inspection of
diaphragms and O-rings is now possible.
Step 10
For Rubber-/TPE-fitted pumps, remove the
outer piston with 7/16" wrench. You are now
able to remove the complete assembly.
Inspection of diaphragms and outer pistons
is now possible.

WIL-10080-E-06 Wilden®
17
Disassembly / Reassembly
Air Valve / Center Section Disassembly
Tools Required:
• 5/32" Hex-Head Wrench
• O-Ring Pick
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 P.025 pump utilizes the revolutionary Pro-Flo air distribution system. A 3.2 mm (1/8") air inlet
connects the air supply to the center section. Proprietary composite seals reduce the coefficient of
friction and allow the P.025 to run lube-free. Constructed of acetal or polypropylene, the Pro-Flo air
distribution system is designed to perform in on/off, non-freezing, non-stalling, tough duty applications.
Step 1
Remove air valve screws from center
section with a 5/32" hex-head wrench.
Step 2
Take care while removing air valve
not to damage gasket.
NOTE: Air valve has
molded- in alignment pins for
proper positioning during
assembly.
Step 3
Remove air valve end cap by simply pulling
it away from air valve body (no tools
required). Inspect O-ring and replace as
needed with genuine Wilden parts.

WIL-10080-E-06 Wilden®
18
Disassembly / Reassembly
Step 4
The air valve spool can now be removed.
A 10-24 UNC (Unified National Coarse)
thread screw can be screwed into the
threaded hole located in the center of the
spool. Grip the screw with pliers and
remove. If a 10-24 UNC screw is not
available, the spool can be tapped out
against a wood block or blown out with
compressed air. Upon reassembly,
lubricate air valve with NLGI grade 2
molybdenum disulfide based grease or
equivalent.
Step 5
Remove the porous polyethylene
muffler element by sliding it toward the
end cap opening. The element can be
cleaned by soaking it in a cleaning
solution (no solvents). If the muffler
restricts the air exhaust, replace muffler
element.
Step 6
Remove pilot spool retaining ring with
an O-ring pick.
Step 7
Push pilot spool through center section and remove. Inspect seals for integrity and spool
for damage. Replace pilot spool assembly if necessary. Upon reassembly of spool, apply a
film of NLGI grade 2 molybdenum disulfide based grease or equivalent (P/N 99-8310-99).

WIL-10080-E-06 Wilden®
19
Disassembly / Reassembly
Reassembly Hints & Tips
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 pump, follow the
disassembly instructions in reverse order. The air distribution
system needs to be assembled first, then the diaphragms,
and finally the wetted parts. Please find applicable torque
specifications in this section.
Rubber/TPE Diaphragm Configuration
There are two types of diaphragm configurations available
for the P.025: 1) Rubber or TPE diaphragm, and 2) PTFE
primary diaphragm with backup O-ring. Observe the "This
Side Out" marking on the convex side of the diaphragm.
Install the disc spring, inner piston, diaphragm, backup O-ring
(PTFE -fitted models only), and the outer piston to main shaft
assembly.
NOTE: PTFE-fitted pumps employ an integral piston
diaphragm). Add a small amount of Loctite 242 to the
bore of the main shaft. Set up time is 20 minutes.
Tighten outer piston to torque value found below.
PTFE Diaphragm Configuration
Lubricate the main shaft assembly with NLGI grade 2 molybdenum
disulfide based grease or equivalent and insert through main shaft
bore in center section. Assemble the other side and torque to proper
value as listed below. Please review the photos above for proper
alignment
PRO-FLO
®
MAXIMUM TORQUE SPECIFICATIONS
Description of Part
Torque
Air Valve
2.3 N•m (20 in-lb)
Outer Piston, Rubber and TPE Diaphragms
4.6 N•m (40 in-lb)
Clamp Band
2.3 N•m (20 in-lb)
Manifold Bolt
5.6 N•m (50 in-lb)
•Apply a small amount of Loctite 242 to the internal threads of the shaft prior to reassembly.

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20
EXPLODED VIEW AND PARTS LISTING
P.025 METAL
RUBBER/TPE - FITTED
EXPLODED VIEW
.
Section 8
Stainless Steel &
Hastelloy®
seating
configuration
23