AIRLESSCO LP540 Hi Boy B Series Use and care manual

3A1190H
EN
Operation/Repair/Parts
Airless Paint Sprayer
For portable spray application of architectural paints and coatings. For professional use
only.
Airlessco Home Depot LP540 Hi Boy (331861) Series B
3000 psi (20.7 MPa, 207 bar) Maximum Working Pressure
IMPORTANT SAFETY INSTRUCTIONS
Read all warnings and instructions in this manual. Be
familiar with the controls and the proper usage of the
equipment. Save these instructions.
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3172585
Certified to CAN/CSA C22. No. 68
Conforms to UL 1450

Warnings
23A1190H
Warnings
The following warnings are for the setup, use, grounding, maintenance, and repair of this equipment. The exclama
tion point symbol alerts you to a general warning and the hazard symbols refer to procedure-specific risks. When
these symbols appear in the body of this manual or warning labels, refer back to these Warnings. Product-specific
hazard symbols and warnings not covered in this section may appear throughout the body of this manual where
applicable.
WARNING
WARNINGWARNING
GROUNDING
This product must be grounded. In the event of an electrical short circuit, grounding reduces the risk of
electric shock by providing an escape wire for the electric current. This product is equipped with a cord
having a grounding wire with an appropriate grounding plug. The plug must be plugged into an outlet that
is properly installed and grounded in accordance with all local codes and ordinances.
• Improper installation of the grounding plug is able to result in a risk of electric shock.
• When repair or replacement of the cord or plug is required, do not connect the grounding wire to either
flat blade terminal.
• The wire with insulation having an outer surface that is green with or without yellow stripes is the
grounding wire.
• Check with a qualified electrician or serviceman when the grounding instructions are not completely
understood, or when in doubt as to whether the product is properly grounded.
• Do not modify the plug provided; if it does not fit the outlet, have the proper outlet installed by a qual
ified electrician.
• This product is for use on a nominal 120V circuit and has a grounding plug similar to the plug illustrated
in the figure below.
• Only connect the product to an outlet having the same configuration as the plug.
• Do not use an adapter with this product.
Extension Cords:
• Use only a 3-wire extension cord that has a grounding plug and a grounding receptacle that accepts
the plug on the product.
• Make sure your extension cord is not damaged. If an extension cord is necessary, use 12 AWG (2.5
mm2) minimum to carry the current that the product draws.
• An undersized cord results in a drop in line voltage and loss of power and overheating.
120V US

Warnings
3A1190H 3
WARNING
WARNINGWARNING
FIRE AND EXPLOSION HAZARD
Flammable fumes, such as solvent and paint fumes, in work area can ignite or explode. To help prevent
fire and explosion:
• Do not spray or clean with materials having flash points lower than 100° F (38° C). Use only non-flam
mable or water-based materials, or non-flammable paint thinners. For complete information about
your material, request the SDS from the material distributor or retailer.
• Do not spray flammable or combustible materials near an open flame or sources of ignition such as
cigarettes, motors, and electrical equipment.
• Paint or solvent flowing through the equipment is able to result in static electricity. Static electricity cre
ates a risk of fire or explosion in the presence of paint or solvent fumes. All parts of the spray system,
including the pump, hose assembly, spray gun, and objects in and around the spray area shall be
properly grounded to protect against static discharge and sparks. Use Graco conductive or grounded
high-pressure airless paint sprayer hoses.
• Verify that all containers and collection systems are grounded to prevent static discharge. Do not use
pail liners unless they are anti-static or conductive.
• Connect to a grounded outlet and use grounded extension cords. Do not use a 3-to-2 adapter.
• Do not use a paint or a solvent containing halogenated hydrocarbons.
• Do not spray combustible liquids in a confined area.
• Keep spray area well-ventilated. Keep a good supply of fresh air moving through the area.
• Spray generates sparks. Keep pump assembly in a well-ventilated area at least 20 feet (6.1 m) from
the spray area when spraying, flushing, cleaning, or servicing. Do not spray pump assembly.
• Do not smoke in the spray area or spray where sparks or flame is present.
• Do not operate light switches, engines, or similar spark producing products in the spray area.
• Keep area clean and free of paint or solvent containers, rags, and other flammable materials.
• Know the contents of the paints and solvents being sprayed. Read all Safety Data Sheets (SDS) and
container labels provided with the paints and solvents. Follow the paint and solvents manufacturer’s
safety instructions.
• Fire extinguisher equipment shall be present and working.
ELECTRIC SHOCK HAZARD
This equipment must be grounded. Improper grounding, setup, or usage of the system can cause elec
tric shock.
• Turn off and disconnect power cord before servicing equipment.
• Use only grounded electrical outlets.
• Use only 3-wire extension cords.
• Ensure ground prongs are intact on power and extension cords.
• Do not expose to rain. Store indoors.

Warnings
43A1190H
SKIN INJECTION HAZARD
High-pressure spray is able to inject toxins into the body and cause serious bodily injury. In the event
that injection occurs, get immediate surgical treatment.
• Do not aim the gun at, or spray any person or animal.
• Keep hands and other body parts away from the discharge. For example, do not try to stop leaks with
any part of the body.
• Always use the nozzle tip guard. Do not spray without nozzle tip guard in place.
• Use Graco nozzle tips.
• Use caution when cleaning and changing nozzle tips. In the case where the nozzle tip clogs while
spraying, follow the Pressure Relief Procedure for turning off the unit and relieving the pressure
before removing the nozzle tip to clean.
• Equipment maintains pressure after power is shut off. Do not leave the equipment energized or under
pressure while unattended. Follow the Pressure Relief Procedure when the equipment is unat
tended or not in use, and before servicing, cleaning, or removing parts.
• Check hoses and parts for signs of damage. Replace any damaged hoses or parts.
• This system is capable of producing 3000 psi. Use Graco replacement parts or accessories that are
rated a minimum of 3000 psi.
• Always engage the trigger lock when not spraying. Verify the trigger lock is functioning properly.
• Verify that all connections are secure before operating the unit.
• Know how to stop the unit and bleed pressure quickly. Be thoroughly familiar with the controls.
EQUIPMENT MISUSE HAZARD
Misuse can cause death or serious injury.
• Always wear appropriate gloves, eye protection, and a respirator or mask when painting.
• Do not operate or spray near children. Keep children away from equipment at all times.
• Do not overreach or stand on an unstable support. Keep effective footing and balance at all times.
• Stay alert and watch what you are doing.
• Do not operate the unit when fatigued or under the influence of drugs or alcohol.
• Do not kink or over-bend the hose.
• Do not expose the hose to temperatures or to pressures in excess of those specified by Graco.
• Do not use the hose as a strength member to pull or lift the equipment.
• Do not spray with a hose shorter than 25 feet.
• Do not alter or modify equipment. Alterations or modifications may void agency approvals and create
safety hazards.
• Make sure all equipment is rated and approved for the equipment in which you are using it.
PRESSURIZED ALUMINUM PARTS HAZARD
Use of fluids that are incompatible with aluminum in pressurized equipment can cause serious chemical
reaction and equipment rupture. Failure to follow this warning can result in death, serious injury, or prop
erty damage.
• Do not use 1,1,1-trichloroethane, methylene chloride, other halogenated hydrocarbon solvents or flu
ids containing such solvents.
• Do not use chlorine bleach.
• Many other fluids may contain chemicals that can react with aluminum. Contact your material supplier
for compatibility.
WARNING
WARNINGWARNING

Warnings
3A1190H 5
MOVING PARTS HAZARD
Moving parts can pinch, cut or amputate fingers and other body parts.
• Keep clear of moving parts.
• Do not operate equipment with protective guards or covers removed.
• Pressurized equipment can start without warning. Before checking, moving, or servicing equipment,
follow the Pressure Relief Procedure and disconnect all power sources.
TOXIC FLUID OR FUMES HAZARD
Toxic fluids or fumes can cause serious injury or death if splashed in the eyes or on skin, inhaled, or
swallowed.
• Read Safety Data Sheet (SDS) to know the specific hazards of the fluids you are using.
• Store hazardous fluid in approved containers, and dispose of it according to applicable guidelines.
PERSONAL PROTECTIVE EQUIPMENT
Wear appropriate protective equipment when in the work area to help prevent serious injury, including
eye injury, hearing loss, inhalation of toxic fumes, and burns. Protective equipment includes but is not
limited to:
• Protective eyewear, and hearing protection.
• Respirators, protective clothing, and gloves as recommended by the fluid and solvent manufacturer.
CALIFORNIA PROPOSITION 65
This product contains a chemical known to the State of California to cause cancer, birth defects or other
reproductive harm. Wash hands after handling.
WARNING
WARNINGWARNING

Component Identification
63A1190H
Component Identification
A
B
C
D
E
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A Power switch Turns sprayer ON and OFF
B Pressure Control Knob Adjusts pressure. Turn clockwise to increase pressure and coun
terclockwise to decrease pressure.
C Prime/Pressure Relief Valve Primes pump and relieves pressure from gun, hose and tip.
D Prime/Pressure Relief Valve Open Posi
tion
Relieves pressure from gun, hose and tip and primes the unit
when in the open position. Valve is in open position when there is
a wider gap between valve handle and cam body.
Refer to Pressure Relief Procedure, page 7
E Prime/Pressure Relief Valve Closed
Position
Pressurizes system when closed. Valve is in closed position
when there is a slight gap between valve handle and cam body.

Operation
3A1190H 7
Operation
Pressure Relief Procedure
Follow this Pressure Relief Procedure whenever you
stop spraying and before cleaning, checking, servicing,
or transporting equipment.
1. Engage the gun trigger lock. Refer to the separate
instruction manual provided with gun for safety fea
tures and how to engage the trigger lock.
2. Turn the unit off.
3. Disengage the gun trigger lock and trigger the gun
to relieve residual fluid pressure.
Hold metal part of the gun in contact with
grounded metal pail. Use minimum pressure.
4. Turn Prime/Pressure Relief Valve to the open (prim
ing) position to relieve residual pressure.
There will be a wider gap between valve handle
and cam body when in open position. In the
closed position there is only a very slight gap.
The valve handle can move both clockwise and counter
clockwise and can face different directions.
5. Re-engage gun trigger lock and close Prime/Pres
sure Relief Valve.Turn Prime/Pressure Relief Valve
to the open (priming) position to relieve residual
pressure.
If the spray tip or hose is clogged, follow Steps 1
through 5 above. Expect paint to splash into the
bucket while relieving pressure during Step 4.
If you suspect that pressure hasn’t been relieved due to
damaged Prime/Pressure Relief Valve, or other reason,
engage the gun trigger lock and then very slowly loosen
the tip nut or hose end coupling to relieve pressure
gradually, then loosen completely and clear obstruction.
Setup
Connect the hose and gun
1. Remove the plastic cap plug from the outlet and
screw a conductive or grounded 3000 psi spray
hose onto fluid outlet.
2. Connect an airless spray gun to the other end of the
hose. Do not install spray tip.
Do not use thread sealer on swivel unions as they are
made to self seal.
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• To reduce the risk of static sparking, fire or explo
sion which can result in serious bodily injury and
property damage, always ground the sprayer and
system components and the object being sprayed,
as instructed in the safety warning section of this
manual.
• Ensure electrical service is 120 VAC, 15 amp min
imum and the outlet is properly grounded.
• For generator power, a minimum 7000 watt gen
erator with a voltage regulation must be used.
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Operation
83A1190H
Fill the Packing Nut/Wet Cup
1. Fill the Packing Nut/Wet Cup with 5 drops of Air
lessco Throat Seal Oil (TSO).
Flush the Sprayer
1. Flush the sprayer. See Flushing Procedure, page
8.
Prime and Flush Storage Fluid
Before beginning a new spraying project you need to
prime the sprayer and flush the storage fluid out of the
sprayer.
Oil- or Water-based Materials
• When changing from water-based material to oil
based material, flush with soapy water and then
mineral spirits.
• When changing from oil based material to water
base material, flush with mineral spirits, followed by
soapy water, then a clean water flush.
• When flushing with solvents, ground pail and gun.
• Flush before changing colors, before fluid can dry in
the equipment, at the end of the day, before storing,
and before repairing equipment.
Flushing
1. Make sure the gun trigger lock in engaged and there
is no spray tip in the gun. Refer to the separate
instruction manual provided with gun for safety fea
tures and how to engage the trigger lock.
2. Pour enough clean, compatible solvent into a large,
empty metal pail to fill the pump and hoses.
3. Place the suction tube into the pail or place the pail
under the pump.
4. Turn Pressure Control Knob to low.
NOTICE
The equipment was tested with lightweight oil, which
is left in the fluid passages to protect parts. To avoid
contaminating your fluid with oil, flush the equipment
with a compatible solvent before using the equipment
for the first time.
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• To reduce the risk of static sparking, which can
cause fire or explosion.
• Always hold a metal part of the gun firmly against
the metal pail when flushing. This also reduces
splashing.
• Always remove the spray tip before flushing.
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High Pressure

Operation
3A1190H 9
5. Open the prime/pressure relief valve to the open -
“Priming Position”. This will allow an easy start.
6. Turn the unit ON/OFF switch to ON.
7. Point the gun into the metal pail and hold a metal
part of the gun firmly against the pail. Maintain firm
metal to metal contact between gun and container.
8. Disengage the gun trigger lock and squeeze the
trigger. At the same time, slowly turn the pressure
control knob clockwise, just enough to move liquid
at low pressure.
9. Allow the pump to operate until clean solvent comes
from the gun.
10. Release the trigger and engage the gun trigger lock.
11. If you are going to start spraying, place the pump or
suction tube into the supply container. Release the
gun trigger lock and trigger the gun into another
empty, metal container, holding a metal part of the
gun firmly against the metal pail, forcing the solvent
from the pump and hose. When paint starts coming
from gun, turn pressure control knob to minimum
pressure, place prime/pressure relief valve in prime
(open) position and engage the gun trigger lock.
12. If you are going to store the sprayer, remove the
suction tube or pump from the solvent pail, force the
solvent from the pump and hose. Engage the gun
trigger lock. See Storage, 10.
13. Whenever shutting down the sprayer, follow Pres
sure Relief Procedure, page 7.
Startup
1. Prepare the material according to the material man
ufacturer’s recommendations.
2. Place the suction tube into the material container.
3. Start the sprayer.
a. Prime/PR Valve must be “OPEN” in the priming
position.
b. After ensuring the gun trigger lock is engaged,
attach tip and safety guard.
c. Turn the unit ON/OFF switch to the “ON” posi
tion.
d. Turn the Pressure Control Knob clockwise to
prime the pump.
e. After the pump is primed, turn the Prime/PR
Valve to the “CLOSED” position.
f. Turn Pressure Control Knob to the desired
spray pressure.
g. Disengage the gun trigger lock to begin spray
ing.
Clogged Flat Tip
Should the spray tip become clogged, relieve pressure
from the hose. See Pressure Relief, page 7. Secure
gun with trigger lock, take off guard, take out the tip,
soak in appropriate solvent and clean with a brush. (Do
not use a needle or sharp pointed instrument to clean
the tip. The tungsten carbide is brittle and can chip.)
Closed
(Pressure)
Open
(Priming and Pressure
Relief)
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NOTICE
To prevent damage and freezing during storage,
never leave water in the fluid pump

Operation
10 3A1190H
Adjusting the Pressure
When adjusting the pressure, turn the Pressure Control
Knob clockwise to increase pressure and counterclock
wise to decrease pressure. Always use the lowest pres
sure necessary to completely atomize the material. If
more coverage is needed, use a larger tip rather than
increasing the pressure.
Operating the sprayer at higher pressure than needed
wastes material, causes early tip wear, and shortens
sprayer life.
Check the spray pattern. The tip size and angle deter
mines the pattern width and flow rate.
Shutdown
1. Relieve Pressure, page 7.
2. Clean the tip and gun as recommended in the sepa
rate Gun Manual supplied with the gun.
3. If spraying water-based material or a material that
could harden in the sprayer overnight, flush the
sprayer after use. See Flushing, page 8.
Storage
Short Term
1. Flush sprayer with compatible solvent before stor
ing, then fill the pump and hoses with an oil based
solvent such as mineral spirits or Airlessco Pump
Conditioner.
• For oil base paint: flush with mineral spirits
• For water-base paint: flush with water, then min
eral spirits and leave the pump, hose and gun
filled with mineral spirits.
Long Term
For longer storage, use Airlessco Pump Conditioner.
Shut off sprayer, Relieve Pressure, page 7, and make
sure prime/pressure relief valve is left open.
Start Up After Storage
Before using water-base paint, flush sprayer with soapy
water and then a clean water flush. When using oil-base
paint, flush out the mineral spirits with the material to be
sprayed.
Always store unit indoors.
• To reduce the risk of injection, never hold your
hand, body, fingers or hand in a rag in front of the
spray tip when cleaning or checking for a cleared
tip. Always point the gun toward the ground or into
a waste container when checking to see if the tip is
cleared or when using a self cleaning tip.
• When you spray into the paint bucket, always use
the lowest spray pressure and maintain firm metal
to metal contact between the gun and container.
• To stop the unit in an emergency, turn the engine
off. Then relieve the fluid pressure in the pump
and hose. See Pressure Relief Procedure, page
7.

Maintenance
3A1190H 11
Maintenance
Daily Maintenance
1. Keep the displacement pump packing nut/wet cup
lubricated with Airlessco TSO (Throat Seal Oil) at all
times. The TSO helps protect the rod and packings.
2. Inspect the packing nut daily. If seepage of paint
into the packing nut and/or movement of the piston
upward is found (while not spraying), the packing
nut should be tightened just enough to stop leakage
(torque is 24 in-lbs). Overtightening will damage the
packings and reduce the packing life.
Electric Motor Maintenance
Lubrication
The motor is supplied with pre-lubricated ball bearings,
lubricated for the life of the bearing.
Motor Brushes
Motor brushes need periodic inspection and replace
ment as wear indicates. Standard brushes have an ini
tial length of 1” and should be replaced when they are
worn to a length of 1/2”. Brush wear is greatly influenced
by individual application and it is recommended that
brush wear be checked at early intervals of operation in
order to determine future required inspection.
To change the brushes:
1. Unplug the machine.
2. Open the two covers at the rear of the motor.
3. Push the brush retainer clip in and withdraw.
4. Disconnect the brush wire.
5. Pull out the wire.
6. Remove the worn brushes.
7. Install new brushes in the reverse order.
To increase brush life, new brushes (Part #331780 for
110 volt) need to have a run in period. After changing
brushes, set the machine for spraying. With a bucket of
Pump Conditioner and water, a 50’ 1/4” airless hose, air
less gun and tip on unit, open the prime/pressure relief
valve and switch on. The pump will now prime. With
pump running in the prime mode, turn the pressure con
trol knob to high pressure. (The pump has to cycle fast
with no pressure in the pump). Run the pump for 20 min
utes and the brushes will be run in.
Servicing the Fluid Pump
Fluid Pump Disconnect
1. Relieve Pressure, page 7.
2. Flush the material you are spraying out of the
machine.
3. Remove the rigid fluid tube (16).
4. Remove the connecting rod shield(12).
5. Move the piston rod (10) to its lowest position by
cycling pump slowly.
6. Turn off the motor and disconnect power from unit.
7. Disconnect fluid tube (16) from pump body.
8. Remove the retaining ring (4) from the connecting
rod (2) and slide the sleeve (3) down revealing the
connecting rod pin (1).
9. Using a 1/2” wrench, unscrew the two bolts (8) from
the cover assembly (14). The fluid pump (9) will be
hanging loosely at this point.
10. Remove the connecting rod pin (1) out of the con
necting rod (2), allowing the removal of the fluid
pump (9) from the machine.
331780
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Maintenance
12 3A1190H
Fluid Pump Reinstall
1. Loosen the packing nut and ensure that the piston
rod (10) is in its upper position in the fluid pump
body, snap cap onto packing nut and slip the sleeve
(3) and the retaining ring (4) over the piston rod
(10).
2. Push the piston rod (10) up into the connecting rod
(2) and align the holes. Insert the connecting rod pin
(1) through the connecting rod (2) and piston. Slip
the sleeve (3) up over the connecting rod pin (1) and
insert the retaining ring (4) into the groove on the
connecting rod (2).
3. Push the two bolts (8) through the tube spacers (11)
and screw them into the cover assembly. Using a
1/2” wrench, tighten the two bolts (8) evenly (alter
nating between them) until you reach 30 ft-lbs.
4. Reassemble lower suction valve assembly by plac
ing the suction seat, O-ring, suction ball and suction
ball guide in the suction nut (7) and screw onto fluid
pump body.
5. Reconnect the fluid tube (16) to the fluid pump
body.
6. Start the machine and operate slowly to check the
piston rod (10) for binding. Adjust the two bolts (8),
holding the fluid pump body to the cover assembly,
if necessary. This will eliminate any binding.
7. Tighten packing nut clockwise until resistance is felt
against the Belleville Springs, go 3/4 of a turn more.
Put five drops of Airlessco Throat Seal Oil in the
packing nut.
8. Run the machine at full pressure for several min
utes. Release the pressure by following the Pres
sure Relief Procedure, page 7, and readjust the
packing nut per step 7 above.
9. Install the connection rod shield (12) so the small
hole is in the upper right hand corner.
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14
2
3
4
1
1
8
9
10
16
12
7
1

Maintenance
3A1190H 13
Servicing the Inlet Valve
1. Un-thread and remove suction nut from the fluid
pump body (8).
2. Remove suction seat (12), O-ring (11), suction ball
(10) and ball guide (9).
3. Clean all parts and inspect them for wear or dam
age, replacing parts as needed.
4. Clean inside of the fluid pump body (8).
5. Reassemble lower suction valve assembly by plac
ing the suction seat (12), O-ring (11), suction ball
(10) and suction ball guide (9) in the suction nut (13)
and screw onto fluid pump body (8).
Packing Replacement
Procedures
Disassembly of the Fluid Pump
1. Disconnect the Fluid Pump, page 11.
2. Unscrew and remove the packing nut, with wet cup
cap.
3. Push the piston rod down through the packings and
out of the pump.
4. Now push the packing removal tool up through the
pump and remove from the top bringing packings,
spacer and springs along with it, leaving fluid body
empty.
Make sure all old packings and glands have been
removed from fluid pump.
5. Clean inside of fluid body.
6. Disassemble all parts and clean for reassembly.
Discard any old packings.
7. Lubricate leather packing in lightweight oil for 10
minutes prior to reassembly.
Reassembly of the Fluid Pump
1. Place lower male gland(1) down on the flat side.
2. Take three of the lower polyethylene packings (2)
and two of the leather packings (23) and place onto
the male gland (1), with the inverted side down, in
the following order:
• Polyethylene
• Leather
• Polyethylene
• Leather
• Polyethylene
3. Take the female adaptor (3), which is inverted on
both sides, and place it on top of your assembled
lower packings.
4. Follow step 2 with your packings inverted side up.
5. Take the second lower male gland (1) and place it
on top of your assembled packings with rounded
side down.
6. Take assembled glands and packings (13 pieces)
and slide onto the lower half of the piston (14).
7. Take the spacer (15) and slide over the top of the
piston (14).
8. Take three spring washers (16) and slide over the
top of the piston (14) in the following order:
• First spring - curve facing up
• Second spring - curve facing down
• Third spring - curve facing up
9. Take the upper male gland (17) and place it
rounded side up.
8
9
10
11
12
13
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Maintenance
14 3A1190H
10. Take three upper polyethylene packings (18) and
two leather packings (22) and assemble with
inverted side down, on to the male gland (17) in the
following order:
• Polyethylene
• Leather
• Polyethylene
• Leather
• Polyethylene
11. Take upper female gland (19) and place on top of
assembled upper packings with the inverted side
down.
12. Take assembled upper glands and packings (7
pieces) and slide on over the top of the piston (14),
making sure inverted sides are down.
13. Take the packing holder (20) and replace the white
O-ring (24) and the black O-ring (25) with new ones
from the packing kit.
14. Slide the packing holder (20) over the top fo the
upper packings so they fit inside.
15. Lubricate inside of the fluid pump body (4) and the
outside of the packings with a light weight oil.
16. Slide assembly into fluid pump body.
To keep packings secured in correct position, hold the
pump body upside down and push the completed
assembly upwards into the pump body. Once placed
inside, tilt pump body back up to keep all pieces in.
17. Tighten packing nut (21) onto the top of the fluid
pump body and tighten until you feel slight resis
tance against the Belleville Springs (16). Using the
Packing Adjustment Tool, tighten another 3/4 of a
turn.
18. Reinstall Fluid Pump, page 12.
Gear and Pump Assembly
Servicing Gear box Assembly
1. Remove fluid pump. See Fluid Pump Disconnect,
page 11.
2. Remove frame from the gearbox by loosening the
four mounting screws.
3. Separate cover assembly (14) from box by remov
ing bolts (1) from front of cover and back of box and
shoulder bolts (2) from front of cover and back of
box.
4. Lay unit on its back and disassemble gearbox.
5. Inspect bearings (15, 18), Crosshead Assembly
(16), Gearcrank (17) and sleeve bearing (10) inside
cover assembly (14) for wear/damage. Replace
worn/damaged parts.
9
8
7
6
5
4
1
1222
3
222
1
23232323
26
21
20
25
24
19
181818
17
161616
15
14
13
11
12
10
2222
8
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Maintenance
3A1190H 15
6. If gear grease needs replacing, replace with gear
grease (Part No. 114819).
7. Clean mating surfaces of cover and box thoroughly.
use Part No. 342899 Instant Gasket.
8. Reassemble in reverse order.
Replacement of Electrical
Components
Anytime the pressure control assembly, sensor, or both
are replaced, perform the calibrations.
Pressure Control Assembly (Electrical
Control Board)
1. Unplug machine’s power cord.
2. Remove six screws heatsink housing.
3. Disconnect all leads from pressure control
assembly.
4. Reassemble in reverse order
5. Torque to 30 ft-lbs.
NOTE: Ensure ground lead (A) is connected to bolt
below control board.
Sensor
1. Remove the four screws, heatsink, and lower the
pressure control assembly.
2. Disconnect sensor lead from the board.
3. Unscrew sensor by holding sensor with 3/4” wrench.
4. Reassemble in reverse order. Torque to 30 ft-lbs.
Potentiometer
1. Lower pressure control assembly as described
above.
2. Disconnect potentiometer lead from pressure con
trol assembly.
3. Use a 1/16” allen wrench, loosen set screw in the
poteniometer knob and remove knob and spacer.
4. Using a 1/2” wrench or deep socket, remove the nut
from the potentiometer shaft assembly.
5. Pull entire potentiometer assembly out of the termi
nal box.
6. Replace in reverse order.
To avoid electric shock, always unplug the electrical
cord before servicing the machine.
12
18
4
17
16
15
14
6
5
7
8
13
10
11
12
2
1
ti16058b
NOTICE
Unit will not operate if wires are disconnected or
pinched. Upon reassembly, ensure all wires are con
nected and not pinched.
NOTICE
Unit will not operate if wires are disconnected or
pinched. Upon reassembly, ensure all wires are con
nected and not pinched.
NOTICE
Unit will not operate if wires are disconnected or
pinched. Upon reassembly, ensure all wires are con
nected and not pinched.
ti26349a

Maintenance
16 3A1190H
On-Off Toggle Switch
1. Lower the pressure control assembly as described
above.
2. Disconnect the two wires on the toggle switch.
3. Use a 9/16” wrench to loosen the nut on the toggle
switch shaft.
4. Reassemble in reverse order.
Liquid Crystal Display (LCD)
1. Lower pressure control assembly as described
above.
2. Unscrew the two nuts (M3) and remove LCD Dis
play assembly.
3. If unable to loosen the two nuts, hold them and
unscrew the two screws. Then remove the LCD Dis
play Assembly.
4. Reassemble in reverse order, while making sure
that the two spacers and the two washers are in
place. Tighten the two nuts handtight and seal with
blue loctite. Do not overtighten the nuts as this will
damage the display.
NOTICE
Unit will not operate if wires are disconnected or
pinched. Upon reassembly, ensure all wires are con
nected and not pinched.
NOTICE
Unit will not operate if wires are disconnected or
pinched. Upon reassembly, ensure all wires are con
nected and not pinched.

Troubleshooting
3A1190H 17
Troubleshooting
General
Problem Cause Solution
Unit doesn’t prime Airleak due to loose suction nut Tighten suction nut.
Airleak due to worn o-rings Replace o-ring (108526) on suction seat and
o-ring (867370) below suction seat.
Airleak due to hole in suction
hose
Replace suction hose.
Stuck or fouled balls Service inlet and outlet valves.
Unit primes but has poor or no
pressure
Pressure set too low Turn up pressure.
Filter(s) are clogged Clean or replace gun filter, inlet filter, and/or
manifold filter.
Outlet valve fouled/worn. Service outlet valve.
Prime/pressure relief valve
bypassing
Clean or replace prime/pressure relief valve
(866428).
Packings and/or piston worn Tighten packing nut, repack unit.
Unit does not maintain good
spraying pressure
Blown spray tip Replace spray tip.
Packings and/or pistons worn Repack unit.
Upper seat worn Replace upper seat.
Unit does not run Tripped Breaker Reset breaker
Electrical Failure See Machine Does Not Start
Electrical
Problem Cause Solution
Machine does not start Control Settings Make sure machine is plugged into the wall.
Verify the on-off switch is in the ON position
and the pressure control knob is turned all the
way to the right (clockwise for maximum pres
sure).
Thermal Breaker Use multi-meter to test the breaker for continu
ity or replace with a new breaker. If breaker
reads good, see Power Source.
Pressure Control Assembly
(Board)
If the power indicating light is still out after
checking the control settings and power source,
replace the pressure control assembly.

Troubleshooting
18 3A1190H
Motor Remove the motor brush covers and turn the
machine ON. Set the potentiometer (POT) at
maximum pressure and check for DC voltage
across both brush terminals. It should read
greater than 80 volts DC.
If you have DC voltage, turn the machine off
and unplug it from the wall. Check to make sure
the brushes are making good contact with the
armature. Replace the brushes if they are less
than 1/2” long. If the brushes are good, replace
the motor.
If you do not have DC voltage, see Sensor.
Sensor Plug another sensor board into the board and
perform the zero calibration procedure. If the
machine starts to run, the sensor is bad. If there
is no replacement sensor available, use a
multi-meter to test the resistance across the red
and black wires of the sensor (be sure to test
the plug). You should read 1.5 - 3.5k ohms. A
faulty sensor usually reads no continuity
(open).
If the sensor passes all the tests, see Pressure
Control Knob (Potentiometer).
Pressure Control Knob (Potenti
ometer)
Plug another potentiometer (POT) into the con
trol board. If the machine starts, the old POT is
bad.
When a replacement POT is not available,
remove the POT lead (with the machine turned
off) from the control board and test the resis
tance between the red and black wires (be sure
to test at the plug). The resistance should read
between 8-12k ohms. If it is outside of this
range replace the POT.
If there is DC voltage at the motor brushes and
the sensor and pressure control knob are func
tioning, replace the pressure control assembly.
Problem Cause Solution

Troubleshooting
3A1190H 19
Pressure Control Repair
Motor Control Board Diagnostics
Keep a new transducer on hand to use for test. 1. For sprayers with digital display, seeDigital Display
Messages, page 20
2. Remove screws and cover.
3. Turn ON/OFF switch ON.
4. Observe LED operation and reference following
table:
Relieve pressure and unplug sprayer before servicing
control board. See Pressure Relief Procedure, page
7.
NOTICE
Do not allow sprayer to develop fluid pressure with
out transducer installed. Leave prime/pressure relief
valve open if test transducer is used.
LED
BLINKS SPRAYER OPERATION INDICATES WHAT TO DO
Once Sprayer runs Normal operation Do nothing
Two times
repeatedly
Sprayer shuts down and
LED continues to blink two
times repeatedly
Run away pressure. Pressure
greater than 4500 psi (310 bar,
31 MPa) or damaged pressure
transducer.
Replace motor control board or
pressure transducer.
Three times
repeatedly
Sprayer shuts down and
LED continues to blink four
times repeatedly.
Pressure transducer is faulty or
missing
Check transducer connection.
Open prime/pressure relief valve.
Substitute new transducer for
transducer in sprayer. If sprayer
runs, replace transducer.
Four times
repeatedly
Sprayer shuts down and
LED continues to blink four
times repeatedly.
Line voltage is too high Check for voltage supply problems
Five times
repeatedly
Sprayer does not start or
shuts down and LED contin
ues to blink five times
repeatedly
Motor fault Check for locked rotor, shorted wir
ing or disconnected motor. Repair
or replace failed parts.
Six times
repeatedly
Sprayer shuts down and
LED blinks six times repeat
edly
Motor is too hot or there is a fault
in the motor thermal device
Allow sprayer to cool. If sprayer
funs correctly when cool, check
motor fan function and air flow.
Keep sprayer in cool location. If
sprayer does not run when cool
and continues to blink 6 times,
replace motor.
Eight times
repeatedly
Sprayer stops or does not
run
High input voltage Check power source for collect
voltage

Troubleshooting
20 3A1190H
Digital Display Messages
No display does not mean that sprayer is not pressur
ized. Relieve pressure before repair. See Pressure
Relief Procedure, page 7
DISPLAY SPRAYER OPERATION INDICATION ACTION
No Display Sprayer stops. Power is not
applied. Sprayer may be
pressurized.
Loss of power. Check power source. Relieve pres
sure before repair or disassembly.
Sprayer is pressurized.
Power is applied. (Pressure
varies with tip size and pres
sure control setting.)
Normal operation Spray
Sprayer may continue to
run. Power is applied.
Pressure greater than 4500 psi
(310 bar, 31 MPa) or pressure
transducer faulty
Replace pressure control board or
pressure transducer
Sprayer stops. Power is
applied.
Pressure transducer faulty, bad
connection or broken wire.
Check transducer connection.
Open prime/pressure relief valve.
Substitute new transducer for
transducer in sprayer. If sprayer
runs, replace transducer.
Sprayer stops. Power is
applied.
Line voltage too high. Check for voltage supply problem
Sprayer does not start or
stops. Power is applied.
Motor fault Check for locked rotor, shorted wir
ing or disconnected motor. Repair
or replace failed parts.
Sprayer stops. Power is
applied.
Motor is too hot. Allow sprayer to cool. If sprayer
runs correctly when cool, check
motor fan function and air flow.
Keep sprayer in cool location. If
sprayer does not run when cool
and continues to blink 6 times,
replace motor.
Power is applied. Pressure less than 200 psi (14
bar, 1.4 MPa)
Increase pressure if desired.
Prime/pressure relief valve may be
open.
Sprayer stops or does not
start
High input voltage Check power source for correct
voltage