Graco Husky 1590 DB3777 User manual

Installation – Parts List
308441ZAT
EN
1.5-inch AODD pump for fluid transfer applications.
For professional use only.
See Models on page 3 for a list of pump models and descriptions.
120 psi (0.8 MPa, 8 bar) Maximum Fluid Working Pressure
120 psi (0.8 MPa, 8 bar) Maximum Air Input Pressure
Important Safety Instructions
Read all warnings and instructions in this
manual. Save these instructions.
Ex h IIC 66°...135°C Gb
Ex h IIIC T135°C Db
ATEX T-code rating is dependent on the temperature
of the fluid being pumped. Fluid temperature is limited
by the materials of the pump interior wetted parts.
See Technical Data for the maximum fluid operating
temperature for your specific pump model.
03263B
Model No. DB3777 shown
II 2 GD
ALUMINUM AND STAINLESS STEEL
Husky1590 Air-Operated
Diaphragm Pumps

2 308441ZAT
Table of Contents
Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Repairing the Air Valve . . . . . . . . . . . . . . . . . . . 16
Ball Check Valve Repair . . . . . . . . . . . . . . . . . . 18
Diaphragm Repair . . . . . . . . . . . . . . . . . . . . . . . 19
Bearing and Air Gasket Removal . . . . . . . . . . . 22
Pump Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Repair Kit Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Parts Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Torque Instructions . . . . . . . . . . . . . . . . . . . . . . . . 31
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Performance Chart . . . . . . . . . . . . . . . . . . . . . . . . . 36
Graco Standard Husky Pump Warranty . . . . . . . . 38
Graco Information . . . . . . . . . . . . . . . . . . . . . . . . . 38

308441ZAT 3
Models
*Refer to the Pump Matrix on page 24 to determine the Model No. of your pump.
NOTE: Plus Models include stainless steel center sections.
Model No. Description
*DB3______ Aluminum Pumps
*DC3______ Aluminum Pumps, Remote
*DB4______ Stainless Steel Pumps
*DC4______ Stainless Steel Pumps, Remote
*DBC______ Aluminum BSPT Pumps
*DCC______ Aluminum BSPT Pumps, Remote
*DBD______ Stainless Steel BSPT Pumps
*DBP______ Stainless Steel Pumps with Flanged Manifold Ports (Vertical Outlet)
*DBR______ Stainless Steel Pumps with Flanged Manifold Ports (Horizontal Outlet)
*DCD______ Stainless Steel BSPT Pumps, Remote
*DT4______ Stainless Steel Plus Pumps
*DU4______ Stainless Steel Plus Pumps, Remote
*DT7______ Stainless Steel Pumps, Type 3.1 Certification
*DT8______ Stainless Steel Pumps, Type 3.1-Advanced Certification
*DTD______ Stainless Steel BSPT Plus Pumps
*DUD______ Stainless Steel BSPT Plus Pumps, Remote
*DTP______ Stainless Steel Pumps with Flanged Manifold Ports (Vertical Outlet)
*DTR______ Stainless Steel Pumps with Flanged Manifold Ports (Horizontal Outlet)
253485 Aluminum Pump
232502 Private-Label Aluminum Pump
24B780 Stainless Steel Plus Pump with overmolded diaphragms
24B781 Stainless Steel Pump with overmolded diaphragms
24G411 Aluminum BSPT Pump with overmolded diaphragms
24J358 Aluminum Pump with overmolded diaphragms
24J359 Aluminum Pump with overmolded diaphragms
25A017 Aluminum Pump with overmolded diaphragms, SST balls
25C654 Stainless Steel Pump with SST Center Section, Flanged Manifold Ports (Horizontal Outlet), and
overmolded diaphragms
25C655 Stainless Steel Pump with Aluminum Center Section, Flanged Manifold Ports (Horizontal Outlet),
and overmolded diaphragms
25C656 Stainless Steel Pump with SST Center Section, Flanged Manifold Ports (Vertical Outlet), and
overmolded diaphragms
25C657 Stainless Steel Pump with Aluminum Center Section, Flanged Manifold Ports (Vertical Outlet),
and overmolded diaphragms
26C239 Same as DB3321, except SST diaphragm fluid plates

4 308441ZAT
Symbols
Warning Symbol Caution Symbol
WARNING
This symbol alerts you to the possibility of serious
injury or death if you do not follow the instructions.
CAUTION
This symbol alerts you to the possibility of damage to
or destruction of equipment if you do not follow the
instructions.
WARNING
INSTRUCTIONS
EQUIPMENT MISUSE HAZARD
Equipment misuse can cause the equipment to rupture or malfunction and result in serious injury.
•This equipment is for professional use only.
•Read all instruction manuals, tags, and labels before operating the equipment.
•Use the equipment only for its intended purpose. If you are not sure, call your Graco distributor.
•Do not alter or modify this equipment. Use only genuine Graco parts and accessories.
•Check equipment daily. Repair or replace worn or damaged parts immediately.
•Do not exceed the maximum working pressure of the lowest rated component in your system. This
equipment has a 120 psi (0.8 MPa, 8 bar) maximum working pressure at 120 psi (0.8 MPa, 8 bar)
maximum incoming air pressure.
•Use fluids and solvents which are compatible with the equipment wetted parts. Refer to the Technical
Data section of all equipment manuals. Read the fluid and solvent manufacturer’s warnings.
•Do not use 1,1,1-trichloroethane, methylene chloride, other halogenated hydrocarbon solvents or fluids
containing such solvents in pressurized aluminum equipment. Such use could result in a chemical
reaction, with the possibility of explosion.
•Do not use hoses to pull equipment.
•Route hoses away from traffic areas, sharp edges, moving parts, and hot surfaces. Do not expose Graco
hoses to temperatures above 82C (180F) or below -40C (-40F).
•Do not lift pressurized equipment.
•Comply with all applicable local, state, and national fire, electrical, and safety regulations.

308441ZAT 5
TOXIC FLUID HAZARD
Hazardous fluid or toxic fumes can cause serious injury or death if splashed in the eyes or on the skin,
inhaled, or swallowed.
•Know the specific hazards of the fluid you are using.
•Store hazardous fluid in an approved container. Dispose of hazardous fluid according to all local, state
and national guidelines.
•Always wear protective eyewear, gloves, clothing and respirator as recommended by the fluid and
solvent manufacturer.
•Pipe and dispose of the exhaust air safely, away from people, animals, and food handling areas. If the
diaphragm fails, the fluid is exhausted along with the air. See Air Exhaust Ventilation on page 11.
FIRE AND EXPLOSION HAZARD
Improper grounding, poor ventilation, open flames or sparks can cause a hazardous condition and result in a
fire or explosion and serious injury.
•Ground the equipment. Refer to Installation on page 7.
•If there is any static sparking or you feel an electric shock while using this equipment, stop pumping
immediately. Do not use the equipment until you identify and correct the problem.
•Provide fresh air ventilation to avoid the buildup of flammable fumes from solvents or the fluid being
sprayed.
•Pipe and dispose of the exhaust air safely, away from all sources of ignition. If the diaphragm fails, the
fluid is exhausted along with the air. See Air Exhaust Ventilation on page 11.
•Keep the work area free of debris, including solvent, rags, and gasoline.
•Electrically disconnect all equipment in the work area.
•Extinguish all open flames or pilot lights in the work area.
•Do not smoke in the work area.
•Do not turn on or off any light switch in the work area while operating or if fumes are present.
•Do not operate a gasoline engine in the work area.
WARNING

6 308441ZAT
Installation
General Information
•The typical installation shown in FIG. 1 is only a guide
for selecting and installing system components.
Contact your Graco distributor for assistance in
planning a system to suit your needs.
•Always use Genuine Graco Parts and Accessories.
Refer to Product Data Sheet 305646.
•Reference numbers and letters in parentheses refer
to the callouts in the figures and the parts lists on
pages 27-28.
•Lift the pump by grasping the outlet manifold (1)
securely. See FIG. 3 on page 10.
Tightening Screws Before First Use
Before using the pump for the first time, check and
retorque all external fasteners. See Torque
Instructions, page 31. After the first day of operation,
retorque the fasteners. Although pump use varies, a
general guideline is to retorque fasteners every two
months.
Tips to Reduce Cavitation
Cavitation in a diaphragm pump is the formation and
collapse of bubbles in the pumped liquid. Frequent or
excessive cavitation can cause serious damage,
including pitting and early wear of fluid chambers, balls,
and seats. It may result in reduced efficiency of the
pump. Cavitation damage and reduced efficiency both
result in increased operating costs.
Cavitation depends on the vapor pressure of the pumped
liquid, the system suction pressure, and the velocity
pressure. It can be reduced by changing any of these
factors.
1. Reduce vapor pressure: Decrease the temperature
of the pumped liquid.
2. Increase suction pressure:
a. Lower the installed position of the pump relative
to the liquid level in the supply.
b. Reduce the friction length of the suction piping.
Remember that fittings add friction length to the
piping. Reduce the number of fittings to reduce
the friction length.
c. Increase the size of the suction piping.
NOTE: Be sure the inlet fluid pressure does not
exceed 25 % of the outlet working pressure.
3. Reduce liquid velocity: Slow the cyclic rate of the
pump.
Pumped liquid viscosity is also very important but nor-
mally is controlled by factors that are process dependent
and cannot be changed to reduce cavitation. Viscous liq-
uids are more difficult to pump and more prone to cavita-
tion.
Graco recommends taking all the above factors into
account in system design. To maintain pump efficiency,
supply only enough air pressure to the pump to achieve
the required flow.
Graco distributors can supply site specific suggestions to
improve pump performance and reduce operating costs.
Grounding
To reduce the risk of static sparking, ground the pump
and all other equipment used or located in the pumping
area. Check your local electrical code for detailed
grounding instructions for your area and type of
equipment. Ground all of this equipment:
WARNING
Hazardous fluid or toxic fumes can cause
serious injury or death if splashed in the
eyes or on the skin, inhaled, or swallowed.
1. Read TOXIC FLUID HAZARD on page 5.
2. Use fluids and solvents which are compatible with
the equipment wetted parts. Refer to the
Technical Data section of all equipment
manuals. Read the fluid and solvent
manufacturer’s warnings.
WARNING
FIRE AND EXPLOSION HAZARD
This pump must be grounded. Before
operating the pump, ground the system as
explained below. Also, read the section
FIRE AND EXPLOSION HAZARD, on
page 5.

308441ZAT 7
Installation
•Pump: Connect a ground wire and clamp as shown in
FIG. 1. Loosen the grounding screw (W). Insert one
end of a 12 ga (1.5 mm2) minimum ground wire (Y)
behind the grounding screw and tighten the screw
securely. Connect the clamp end of the ground wire
to a true earth ground. Order Part No. 222011
Ground Wire and Clamp.
FIG. 1 ___________________________
•Air and fluid hoses: Use only grounded hoses with a
maximum of 500 ft (150 m) combined hose length to
ensure grounding continuity.
•Air compressor: Follow the manufacturer’s
recommendations.
•All solvent pails used when flushing: Follow the local
code. Use only metal pails, which are conductive. Do
not place the pail on a non-conductive surface, such
as paper or cardboard, which interrupts the
grounding continuity.
•Fluid supply container: Follow the local code.
Mountings
1. Be sure the mounting surface can support the weight
of the pump, hoses, and accessories, as well as the
stress caused during operation.
2. For all mountings, be sure the pump is bolted directly
to the mounting surface.
3. For ease of operation and service, mount the pump
so the air valve cover (2), air inlet, and fluid inlet and
outlet ports are easily accessible.
4. Rubber Foot Mounting Kit 236452 is available to
reduce noise and vibration during operation.
Air Line
1. Install the air line accessories as shown in FIG. 2.
Mount these accessories on the wall or on a bracket.
Be sure the air line supplying the accessories is
grounded.
a. Install an air regulator (C) and gauge to control
the fluid pressure. The fluid outlet pressure will
be the same as the setting of the air regulator.
b. Locate one bleed-type master air valve (B) close
to the pump and use it to relieve trapped air. See
the WARNING above. Locate the other master
air valve (E) upstream from all air line
accessories and use it to isolate them during
cleaning and repair.
c. The air line filter (F) removes harmful dirt and
moisture from the compressed air supply.
2. Install a grounded, flexible air hose (A) between the
accessories and the 1/2 npt(f) pump air inlet (N). See
FIG. 3. Use a minimum 1/2 in. (13 mm) ID air hose.
Screw an air line quick disconnect coupler (D) onto
the end of the air hose (A), and screw the mating
fitting into the pump air inlet snugly. Do not connect
the coupler (D) to the fitting until you are ready to
operate the pump.
CAUTION
The pump exhaust air may contain contaminants.
Ventilate to a remote area if the contaminants could
affect your fluid supply. See Air Exhaust Ventilation
on page 11.
Y
W
02646B
WARNING
A bleed-type master air valve (B) is required in your
system to relieve air trapped between this valve and
the pump. Trapped air can cause the pump to cycle
unexpectedly, which could result in serious injury,
including splashing in the eyes or on the skin, injury
from moving parts, or contamination from hazardous
fluids. See FIG. 2.

8 308441ZAT
Installation
Installation of Remote Pilot Air Lines
1. Refer to Parts Drawing. Connect air line to pump as
in preceding steps.
2. Connect 1/4 in. O.D. tubing to push type connectors
(14) on air motor of pump.
NOTE: by replacing the push type connectors, other
sizes or types of fittings may be used. The new fittings
will require 1/8 in. npt threads.
3. Connect remaining ends of tubes to external air
signal, such as Graco’s Cycleflo (P/N 195264) or
Cycleflo II (P/N195265) controllers.
NOTE: the air pressure at the connectors must be at
least 30% of the air pressure to the air motor for the
pump to operate.
Fluid Suction Line
1. Use grounded fluid hoses (G). The pump fluid inlet
(R) is 1-1/2 in. npt(f). Screw the fluid fitting into the
pump inlet securely.
2. If the fluid inlet pressure to the pump is more than
25% of the outlet working pressure, the ball check
valves will not close fast enough, resulting in
inefficient pump operation.
3. At inlet fluid pressures greater than 15 psi (0.1 MPa,
1 bar), diaphragm life will be shortened.
4. See the Technical Data on page 35 for maximum
suction lift (wet and dry).
Fluid Outlet Line
1. Use grounded fluid hoses (L). The pump fluid
outlet (S) is 1-1/2 in. npt(f). Screw the fluid fitting into
the pump outlet securely.
2. Install a fluid drain valve (J) near the fluid outlet.
See the WARNING above.
3. Install a shutoff valve (K) in the fluid outlet line.
WARNING
A fluid drain valve (J) is required to relieve pressure in
the hose if it is plugged. The drain valve reduces the
risk of serious injury, including splashing in the eyes
or on the skin, or contamination from hazardous fluids
when relieving pressure. Install the valve close to the
pump fluid outlet. See FIG. 2.

308441ZAT 9
FIG. 2 ____________________________________________________________
Y
J
FEB C
A
DKL
G
H
R
S
03265B
Muffler not included
on Model No. 253485
TYPICAL FLOOR-MOUNT INSTALLATION
KEY
A Air supply hose
B Bleed-type master air valve (required for
pump)
C Air regulator
D Air line quick disconnect
E Master air valve (for accessories)
F Air line filter
G Fluid suction hose
H Fluid supply
J Fluid drain valve (required)
K Fluid shutoff valve
L Fluid hose
R Fluid inlet port
S Fluid outlet port
Y Ground wire (required; see page 5 for
installation instructions)

10 308441ZAT
Installation
Changing the Orientation of the Fluid Inlet
and Outlet Ports
NOTE: Remove and rotate the center manifold(s) to
change the orientation of inlet or outlet port(s). Follow the
Torque Instructions, page 31.
KEY
Apply medium-strength (blue) thread locker to the threads. See
Torque Instructions, page 31.
Apply medium-strength (blue) thread locker to the threads. See
Torque Instructions, page 31.
FIG. 3 __________________________
Fluid Pressure Relief Valve
KEY
R 1.5 in. npt(f) fluid inlet port
S 1.5 in. npt(f) fluid outlet port
V Pressure relief valve (Order Part No. 112119 for stainless
steel pumps)
Install valve between fluid inlet and outlet ports.
Connect fluid inlet line here.
Connect fluid outlet line here.
Muffler not included on Model No. 253485
FIG. 4 ___________________________
1
2
N
P
2
1
106
106
102
103
101
1122
03263B
Aluminum Model Shown
N 1/2 in. npt(f) air inlet port
P Muffler. (Not included on
Model No. 253485)
101 Covers
102 Fluid inlet manifold
103 Fluid outlet manifold
106 Manifold and cover
screws
112 Bottom cover screws
CAUTION
Some systems may require installation of a
pressure relief valve at the pump outlet to prevent
overpressurization and rupture of the pump or hose.
See FIG. 4.
Thermal expansion of fluid in the outlet line can
cause overpressurization. This can occur when
using long fluid lines exposed to sunlight or ambient
heat, or when pumping from a cool to a warm area
(for example, from an underground tank).
Overpressurization can also occur if the Husky
pump is being used to feed fluid to a piston pump,
and the intake valve of the piston pump does not
close, causing fluid to back up in the outlet line.
1
2
3
4
R
S
1
2
V
03461B
3
4

308441ZAT 11
Installation
Air Exhaust Ventilation The air exhaust port is 3/4 npt(f). Do not restrict the air
exhaust port. Excessive exhaust restriction can cause
erratic pump operation.
If the muffler (P) is installed directly to the air exhaust
port, apply PTFE thread tape or anti-seize thread
lubricant to the muffler threads before assembly.
To provide a remote exhaust:
1. Remove the muffler (P) from the pump air exhaust
port.
2. Install a grounded air exhaust hose (T) and connect
the muffler (P) to the other end of the hose. The
minimum size for the air exhaust hose is 3/4 in.
(19 mm) ID. If a hose longer than 15 ft (4.57 m) is
required, use a larger diameter hose. Avoid sharp
bends or kinks in the hose. See FIG. 4.
3. Place a container (U) at the end of the air exhaust
line to catch fluid in case a diaphragm ruptures.
VENTING EXHAUST AIR
FIG. 5 ____________________________________________________________
WARNING
FIRE AND EXPLOSION HAZARD
Be sure to read and follow the warnings
and precautions regarding TOXIC FLUID
HAZARD, and FIRE AND EXPLOSION
HAZARD on page 5, before operating this
pump.
Be sure the system is properly ventilated for your type
of installation. You must vent the exhaust to a safe
place, away from people, animals, food handling
areas, and all sources of ignition when pumping
flammable or hazardous fluids.
Diaphragm failure will cause the fluid being pumped
to exhaust with the air. Place an appropriate
container at the end of the air exhaust line to catch
the fluid. See FIG. 5.
03267A
FBEC
A
D
P
T
U
KEY
A Air supply line
B Bleed-type master air valve
(required for pump)
C Air regulator
D Air line quick disconnect
E Master air valve (for accessories)
F Air line filter
P Muffler (not included on Model
No. 253485)
T Grounded air exhaust hose
U Container for remote air exhaust

12 308441ZAT
Operation
Pressure Relief Procedure
1. Shut off the air to the pump.
2. Open the dispensing valve, if used.
3. Open the fluid drain valve to relieve all fluid pressure,
having a container ready to catch the drainage.
Flush the Pump Before First Use
The pump was tested in water. If water could
contaminate the fluid you are pumping, flush the pump
thoroughly with a compatible solvent. Follow the steps
under Starting and Adjusting the Pump.
Starting and Adjusting the Pump
1. Be sure the pump is properly grounded. Refer to
Installation on page 7.
2. Check all fittings to be sure they are tight. Be sure to
use a compatible liquid thread sealant on all male
threads. Tighten the fluid inlet and outlet fittings
securely.
3. Place the suction tube (if used) in the fluid to be
pumped.
NOTE: If the fluid inlet pressure to the pump is more than
25% of the outlet working pressure, the ball check valves
will not close fast enough, resulting in inefficient pump
operation.
4. Place the end of the fluid hose (L) into an appropriate
container.
5. Close the fluid drain valve (J). See FIG. 2.
6. Close the pump air regulator (C). Open all bleed-type
master air valves (B, E).
7. If the fluid hose has a dispensing device, hold it open
while continuing with the following step.
8. Slowly open the air regulator (C) until the pump starts
to cycle. Allow the pump to cycle slowly until all air is
pushed out of the lines and the pump is primed.
If you are flushing, run the pump long enough to
thoroughly clean the pump and hoses. Close the air
regulator. Remove the suction tube from the solvent
and place it in the fluid to be pumped.
Operation of Remote Piloted Pumps
1. Follow preceding steps 1 through 7 of Starting and
Adjusting the Pump.
2. Open air regulator (C).
3. Pump will operate when air pressure is alternately
applied and relieved to push type connectors (14).
NOTE: Leaving air pressure applied to the air motor for
extended periods when the pump is not running may
shorten the diaphragm life. Using a 3-way solenoid valve
to automatically relieve the pressure on the air motor
when the metering cycle is complete prevents this from
occurring.
Pump Shutdown
At the end of the work shift, relieve the pressure.
WARNING
PRESSURIZED EQUIPMENT HAZARD
The equipment stays pressurized until pressure is
manually relieved. To reduce the risk of serious injury
from pressurized fluid, accidental spray from the gun
or splashing fluid, follow this procedure whenever
you:
•Are instructed to relieve pressure,
•Stop pumping,
•Check, clean or service any system equipment,
•Install or clean fluid nozzles.
WARNING
TOXIC FLUID HAZARD
To reduce the risk of serious injury,
splashing in the eyes or on the skin, and
toxic fluid spills, never move or lift a pump
under pressure. If dropped, the fluid section
may rupture. Always follow the Pressure
Relief Procedure above before lifting the
pump.
WARNING
The pump may cycle once before the external signal
is applied. Injury is possible. If pump cycles, wait
until end before proceeding.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure at left.

308441ZAT 13
Maintenance
Lubrication
The air valve is designed to operate unlubricated,
however if lubrication is desired, every 500 hours of
operation (or monthly) remove the hose from the pump
air inlet and add two drops of machine oil to the air inlet.
Tightening Threaded Connections
Before each use, check all hoses for wear or damage,
and replace as necessary. Check to be sure all threaded
connections are tight and leak-free.
Check fasteners. Tighten or retorque as necessary.
Although pump use varies, a general guideline is to
retorque fasteners every two months. See Torque
Instructions, page 31.
Flushing and Storage
Flush the pump often enough to prevent the fluid you are
pumping from drying or freezing in the pump and
damaging it. Use a compatible solvent.
Always flush the pump and relieve the pressure before
storing it for any length of time.
CAUTION
Do not over-lubricate the pump. Oil is exhausted
through the muffler, which could contaminate your
fluid supply or other equipment. Excessive
lubrication can also cause the pump to malfunction.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.

14 308441ZAT
Troubleshooting
•Relieve the pressure before checking or servicing the
equipment.
•Check all possible problems and causes before
disassembling the pump.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
PROBLEM CAUSE SOLUTION
Pump cycles at stall or fails to hold
pressure at stall. Worn check valve balls (301), seats (201) or o-rings (202). Replace. See page 18.
Pump will not cycle, or cycles once
and stops. Air valve is stuck or dirty. Disassemble and clean air valve. See pages 16-17. Use filtered air.
Check valve ball (301) severely worn
and wedged in seat (201) or manifold
(102 or 103).
Replace ball and seat. See page 18.
Check valve ball (301) is wedged into
seat (201), due to overpressurization. Install Pressure Relief Valve (see page 10).
Dispensing valve clogged. Relieve pressure and clear valve.
Pump operates erratically. Clogged suction line. Inspect; clear.
Sticky or leaking balls (301). Clean or replace. See page 18.
Diaphragm ruptured. Replace. See pages 19-21.
Restricted exhaust. Remove restriction.
Air bubbles in fluid. Suction line is loose Tighten.
Diaphragm ruptured. Replace. See pages 19-21.
Loose inlet manifold (102), damaged
sealbetweenmanifoldandseat(201),
damaged o-rings (202).
Tighten manifold bolts (106) or
replace seats (201) or o-rings (202).
See page 18.
Loose diaphragm shaft bolt (107). Tighten or replace. See pages 19-21.
Damaged o-ring (108). Replace. See pages 19-21.

308441ZAT 15
Troubleshooting
PROBLEM CAUSE SOLUTION
Fluid in exhaust air. Diaphragm ruptured. Replace. See pages 19-21.
Loose diaphragm shaft bolt (107). Tighten or replace. See pages 19-21.
Damaged o-ring (108). Replace. See pages 19-21.
Pump exhausts excessive air at stall. Worn air valve block (7), o-ring (6),
plate (8), pilot block (18), u-cups (10),
or pilot pin o-rings (17).
Repair or replace. See pages 16-17.
Worn shaft seals (402). Replace. See pages 19-21.
Pump leaks air externally. Air valve cover (2) or air valve cover
screws (3) are loose. Tighten screws. See page 17.
Air valve gasket (4) or air cover
gasket (22) is damaged. Inspect; replace. See pages 16-17, 22-23.
Air cover screws (25) are loose. Tighten screws. See pages 22-23.
Pump leaks fluid externally from ball
check valves. Loose manifolds (102, 103), damaged sealbetweenmanifoldandseat(201),
damaged o-rings (202).
Tighten manifold bolts (106) or
replace seats (201) or o-rings (202).
See page 18.

16 308441ZAT
Service
Repairing the Air Valve
Tools Required
•Torque wrench
•Torx (T20) screwdriver or 7 mm (9/32 in.) socket
wrench
•Needle-nose pliers
•O-ring pick
•Lithium base grease
NOTE: Air Valve Repair Kits 236273 (aluminum center
housing models) and 255061 (sst center housing models)
are available. Refer to page 28. Parts included in the kit
are marked with a symbol, for example (4†). Use all the
parts in the kit for the best results.
Disassembly
1. Relieve the pressure.
2. With a Torx (T20) screwdriver or 7 mm (9/32 in.)
socket wrench, remove the six screws (3), air valve
cover (2), and gasket (4). See FIG. 6.
3. Move the valve carriage (5) to the center position and
pull it out of the cavity. Remove the valve block (7†)
and o-ring (6†) from the carriage. Using a
needle-nose pliers, pull the pilot block (18) straight up
and out of the cavity. See FIG. 7.
4. Pull the two actuator pistons (11) out of the bearings
(12). Remove the u-cup packings (10) from the
pistons. Pull the pilot pins (16) out of the bearings
(15). Remove the o-rings (17) from the pilot pins. See
FIG. 8.
5. Inspect the valve plate (8) in place. If damaged, use
a Torx (T20) screwdriver or 7 mm (9/32 in.) socket
wrench to remove the three screws (3). Remove the
valve plate (8) and, on aluminum center housing
models only, remove the seal (9). See FIG. 9.
6. Inspect the bearings (12, 15) in place. See FIG. 8.
The bearings are tapered and, if damaged, must be
removed from the outside. This requires disassembly
of the fluid section. See page 22.
7. Clean all parts and inspect for wear or damage.
Replace as needed. Reassemble as explained on
page 17.
FIG. 6 ___________________________
FIG. 7 ___________________________
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
32
4
2
03268B
1
Muffler not included on
Model No. 253485
Torque to 50-60 in-lb
(5.6-68 Nm)
1
2
03269
1851
7
6
5
2
3
3
11
See Detail at right.
Grease.
Grease lower face.
1
2
3

308441ZAT 17
Service
FIG. 8 ___________________________
FIG. 9 ___________________________
Reassembly
1. If you removed the bearings (12, 15), install new
ones as explained on page 22. Reassemble the fluid
section.
2. On aluminum center housing models, install the
valve plate seal (9†) into the groove at the bottom of
the valve cavity. The rounded side of the seal must
face down into the groove. See FIG. 9.
3. Install the valve plate (8) in the cavity. On aluminum
center housing models, the plate is reversible, so
either side can face up. Install the three screws (3),
using a Torx (T20) screwdriver or 7 mm (9/32 in.)
socket wrench. Tighten until the screws bottom out
on the housing. See FIG. 9.
4. Install an o-ring (17†) on each pilot pin (16). Grease
the pins and o-rings. Insert the pins into the bearings
(15), narrow end first. See FIG. 8.
5. Install a u-cup packing (10†) on each actuator
piston (11), so the lips of the packings face the
narrow end of the pistons. See FIG. 8.
6. Lubricate the u-cup packings (10†) and actuator
pistons (11). Insert the actuator pistons in the
bearings (12), wide end first. Leave the narrow end
of the pistons exposed. See FIG. 8.
7. Grease the lower face of the pilot block (18†) and
install so its tabs snap into the grooves on the ends
of the pilot pins (16). See FIG. 7.
8. Grease the o-ring (6†) and install it in the valve
block (7). Push the block onto the valve carriage (5).
Grease the lower face of the valve block. See FIG. 7.
9. Install the valve carriage (5) so its tabs slip into the
grooves on the narrow end of the actuator pistons
(11). See FIG. 7.
10. Align the valve gasket (4†) and cover (2) with the six
holes in the center housing (1). Secure with six
screws (3), using a Torx (T20) screwdriver or 7 mm
(9/32 in.) socket wrench. Torque to 50-60 in-lb
(5.6-6.8 Nm). See FIG. 6.
03270
1716
11
10
12
151
2
3
4
2
Insert narrow end first.
Grease.
Install with lips facing
narrow end of piston (11).
Insert wide end first.
1
2
3
4
03271
8
9
3
1
2
Rounded side must
face down (aluminum
center housing
models only).
Tighten screws until
they bottom out on
the housing.
1
2

18 308441ZAT
Service
Ball Check Valve Repair
Tools Required
•Torque wrench
•13 mm socket wrench
•O-ring pick
Disassembly
NOTE: A Fluid Section Repair Kit is available. Refer to
page 26 to order the correct kit for your pump. Parts
included in the kit are marked with an asterisk, for
example (201*). Use all the parts in the kit for the best
results.
NOTE: To ensure proper seating of the balls (301),
always replace the seats (201) when replacing the balls.
Also, on some models, replace the o-rings (202).
1. Relieve the pressure. Disconnect all hoses.
2. Remove the pump from its mounting.
3. Using a 13 mm socket wrench, remove the four bolts
(106) holding the outlet manifold (103) to the fluid
covers (101). See FIG. 10.
4. Remove the o-rings (202, not used on some models),
seats (201), and balls (301) from the manifold.
5. Turn the pump over and remove the inlet manifold
(102). Remove the o-rings (202, not used on some
models), seats (201), and balls (301) from the fluid
covers (101).
Reassembly
1. Clean all parts and inspect for wear or damage.
Replace parts as needed.
2. Reassemble in the reverse order, following all notes
in FIG. 10. Be sure the ball checks are assembled
exactly as shown. The arrows (A) on the fluid covers
(101) must point toward the outlet manifold (103).
Apply medium-strength (blue) thread locker to the threads. Torque
to 120-150 in-lb (14-17 Nm). See Torque Instructions, page 31.
Arrow (A) must point toward outlet manifold (103).
Not used on some models.
Beveled seating surface must face ball (301).
FIG. 10 __________________________
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
1
2
3
4
03272B
106
103
101
A
201*
301*
106
102
201*
301*
2
1
1
202*
202*
3
3
4
4
3

308441ZAT 19
Service
Diaphragm Repair
Tools Required
•Torque wrench
•13 mm socket wrench
•15 mm socket wrench (aluminum models) or
1 in. socket wrench (stainless steel models)
•19 mm open-end wrench
•O-ring pick
•Lithium-base grease
Disassembly
NOTE: A Fluid Section Repair Kit is available. Refer to
page 23 to order the correct kit for your pump. Parts
included in the kit are marked with an asterisk, for
example (401*). Use all the parts in the kit for the best
results.
1. Relieve the pressure.
2. Remove the manifolds and disassemble the ball
check valves as explained on page 18.
3. Using a 13 mm socket wrench, remove the screws
(106 and 112) holding the fluid covers (101) to the air
covers (23). Pull the fluid covers (101) off the pump.
See FIG. 11.
FIG. 11 ____________________________________________________________
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
23
101
A2
B
1
106
1121
03273C
3
Apply medium-strength (blue) thread locker to the
threads. Torque to 190-220 in-lb (22-25 Nm). See
Torque Instructions, page 31.
Arrow (A) must point toward air valve (B).
Muffler not included on Model No. 253485.
1
2
3

20 308441ZAT
Service
4. Loosen but do not remove the diaphragm shaft bolts
(107), using a 15 mm socket wrench (1 in. on
stainless steel models) on both bolts. NOTE: This
step does not apply to pumps with overmolded
diaphragms.
5. Unscrew one bolt from the diaphragm shaft (24) and
remove the o-ring (108), fluid side diaphragm plate
(105), PTFE diaphragm (403, used on PTFE models
only), diaphragm (401), and air side diaphragm plate
(104). See FIG. 12.
For overmolded diaphragms: Grip both diaphragms
securely around the outer edge and rotate
counterclockwise. One diaphragm assembly will
come free and the other will remain attached to the
shaft. Remove the freed diaphragm and air side
plate.
6. Pull the other diaphragm assembly and the
diaphragm shaft (24) out of the center housing (1).
Hold the shaft flats with a 19 mm open-end wrench,
and remove the bolt (107) from the shaft.
Disassemble the remaining diaphragm assembly.
For overmolded diaphragms: Pull the other
diaphragm assembly and the diaphragm shaft (24)
out of the center housing (1). Hold the shaft flats with
a 19 mm open-end wrench and remove the
diaphragm and air side plate from the shaft.
7. Inspect the diaphragm shaft (24) for wear or
scratches. If it is damaged, inspect the bearings (19)
in place. If the bearings are damaged, refer to page
22.
8. Reach into the center housing (1) with an o-ring pick
and hook the u-cup packings (402), then pull them
out of the housing. This can be done with the
bearings (19) in place.
9. Clean all parts and inspect for wear or damage.
Replace parts as needed.
Reassembly
1. Install the shaft u-cup packings (402*) so the lips face
out of the housing (1). Lubricate the packings. See
FIG. 12.
2. Install the diaphragm assembly on one end of the
shaft (24) as follows. For pumps with overmolded
diaphragms, go directly to step g.
a. Install the o-ring (108*) on the shaft bolt (107).
b. Install the fluid side diaphragm plate (105) on the
bolt so the rounded side faces in, toward the
diaphragm (401).
c. On PTFE models only, install the PTFE
diaphragm (403*). Make certain the side marked
AIR SIDE faces the center housing (1).
d. Install the diaphragm (401*) on the bolt. Make
certain the side marked AIR SIDE faces the
center housing (1).
e. Install the air side diaphragm plate (104) so the
recessed side faces the diaphragm (401).
f. Apply medium-strength (blue) thread locker to
the bolt (107) threads. Screw the bolt (107) into
the shaft (24) hand tight.
g. For overmolded diaphragms: Assemble the air
side plate (104) onto the diaphragm (403). The
wide, radiused side of the plate must face the
diaphragm. Apply medium-strength (blue) thread
locker to the threads of the diaphragm assembly.
Screw the assembly into the shaft (24) hand
tight.
3. Grease the length and ends of the diaphragm shaft
(24), and slide it through the housing (1).
4. Assemble the other diaphragm assembly to the shaft
as explained in step 2.
5. Hold one shaft bolt (107) with a wrench and torque
the other bolt to 20-25 ft-lb (27-34 Nm) at 100 rpm
maximum. NOTE: This step does not apply to pumps
with overmolded diaphragms.
6. Align the fluid covers (101) and the center housing
(1) so the arrows (A) on the covers face the same
direction as the air valve (B). Apply medium-strength
(blue) thread locker to the threads of screws (106)
and (112), and secure the covers with the screws
handtight. Install the longer screws (112) in the
bottom holes of the covers. See Fig. 11. Using a 13
mm socket wrench, torque the screws oppositely and
evenly to 190-220 in-lb (22-25 Nm). See Torque
Instructions, page 31.
7. Reassemble the ball check valves and manifolds as
explained on page 18.