1) Remove the handle and bolt
and set aside. With the pump
facing towards you lay the unit
on its back (Figure 1). Loosen
the hose clamp by unscrewing
the bolt and remove the
sprayer hose. Caution:
There could be residual liquid in the hose and pressure
cylinder. Remove the nut and bolt from the protective
cap and remove the cap (C). Rotate the pump shaft in
order to reach two lever bolts in the center (B). Using a
wrench, remove the lever bolts. Pull the piston (F) out
of the piston cylinder.
2) Remove the piston
cylinder assembly by
turning the piston cylinder
counter-clockwise when
viewing the sprayer from the
bottom. Caution: The piston
cylinder has sharp edges.
3) Check for vertical
scratches on the inside of the
piston cylinder and the
piston. If one or both are
scratched you must replace
them.
4) Remove the connecting
rods from the piston and
lever by inserting a
fl
at head
screwdriver between the two
connecting rods and rotating.
5) Insert the new piston and
replace the lever studs on
the inside of the new piston.
Place the lever studs into
the connecting rods and
snap together.
6) To replace the collar, push
it off of the crown of the
piston with your thumb. You
will see form
fi
tted slots to
install the new collar on to
the piston crown.
7) Remove the valve plate and
O-rings from the outside of the
piston cylinder. Making sure the
O-rings are set properly in the
exposed grooves, install the new
valve plate and the two O-rings. There is a second
valve plate inside the piston cylinder. Pull on the red
or orange pin and remove the valve plate using a #2
Phillipshead screw driver. Install a new valve plate
and reseat the retaining pin
fi
rmly in place using the
#2 Phillipshead screw driver.
8) Assemble the piston cylinder.
Grease the O-ring on the
pistoncylinder (do not get any grease
on the valve plate) and place the
piston cylinder into the pressure
cylinder. Screw the piston
cylinder clockwise until tight and the bottom O-ring is no
longer visible. When properly placed, the notch on the
piston cylinder will line up with the catch on the pressure
cylinder.
9) Apply a little grease to the inside
of the piston cylinder wall on the
collar, and reinstall the piston into
the piston cylinder.
10) Insert the piston at an angle
with the leading edge of the collar
placed over the slot in the piston
cylinder. Install the 6mm Allen
bolts through the lever base and
into the shaft.
11) Replace the cap. Tighten the
nut and bolt. Reinstall the
handle. Replace the hose and
fi
rmly secure the hose clamp
back in place.
DISASSEMBLING AND REPAIRING THE PISTON PUMP
Wear protective gloves when
performing this operation.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 11
Figure 10
Figure 9
7E
CLEANING
1 Always empty the sprayer and clean the tank thoroughly after each use.
2) Pump the sprayer handle until all of the contents and air exit through the nozzle.
3) Fill tank half way with water and pump the water out as explained in step 2 (repeat
several times with highly corrosive materials).
Other Cleaning Hints:
• Improper spray distribution usually means the nozzle is clogged, remove the nozzle and clean it.
• Soap can be added to the water to clean the tank.
• Do not use strong cleaning agents or abrasives.
• If you use a chemical agent to clean the tank follow the manufacturer’s recommendations for the
disposal of the waste water.
• In case of a chemical agent spill activated liquid charcoal (or other form) can be used to absorb
chemicals in the sprayer tank or spills.
Note:
If you are using with hormone weed killers, follow the manufacturers instructions
for the clean up of the herbicide producers, and neutralize with activated charcoal. This is
important if other chemicals are used subsequently since the residue of the herbicide will
damage plants. You can add 0.35 oz./1 g. of activated charcoal to 1.7 pint/1 liter of water
and leave in the tank and the hose lines for about 24 hours. For cleaning after the
application of carbolineum products, especially if they are not water soluble, use a 5% soda
lye with a temperature of 104°F/40°C and rinse with a lot of water.
STORING / MAINTAINING YOUR SPRAYER
A
fi
ne mesh stainless steel screen is on the pressure cylinder inlet to protect the piston,
cylinder and collar. If your sprayer will not empty the tank, check for a clogged inlet
screen (2). The inlet screen is located at the bottom of the pressure cylinder on the back
of the sprayer (the side against your back when in use).
When you let go of the pump handle and it “snaps” to the
down position, it is an indication that the screen needs
cleaning. Clean the screen with a small bristle brush or an old
toothbrush. See diagram to locate the screen.
• The sprayer should be stored out of direct sunlight in a cool
dry space.
•Treat both the collar and the piston with petroleum jelly after
removing the pump or mounting a new collar.
• Before freezing weather make sure to drain all liquid in the
tank, lines and air chamber to avoid liquid expansion and
cracking in the sprayer components (See “Cleaning.”) and
lock the shut-off valve in the “open” position.
• When service is required call your nearest Chapin dealer and always insist on original
Chapin manufactured replacement parts.
• Inspect the hose, wand, pump, tank and shut-off valve for wear, damage or leaks on a
regular basis and repair defects promptly.
Avoid excessive wear by:
1) Regular lubrication of the collar, cylinder and piston with petroleum jelly.
2) Thorough cleaning and
fl
ushing of sprayer with soap and water after each use.
4. Pressure
Control Valve
1. Pressure
Cylinder
2. Inlet Screen
Location
3. Cylinder
Support
SPRAYER COMPONENTS & USE INFORMATION, Continued
4E
