IMPACT 640
2.5
REPLACING THE PRIME/SPRAY VALVE
Perform the following procedure using PRIME/SPRAY valve
replacement kit P/N 700-258
1.
Push the groove pin out of the valve handle.
2.
Remove the valve handle and the cam base.
3.
Using a wrench, loosen and remove the valve housing assembly.
4.
Make sure the gasket is in place and thread the new valve housing
assembly into the pump block. Tighten securely with wrench.
5.
Place the cam base over the valve housing assembly. Lubricate
the cam base with grease and line up the cam with the pump
block.
6.
Line up the hole on the valve stem with the hole in the valve
handle.
7.
Insert the groove pin into the valve handle and through the valve
stem to secure the valve handle in position.
Valve housing
2.6
SERVICING THE FLUID SECTION
Use the following procedures to service the valves and repack the
fluid section. Perform the following steps before performing any
maintenance on the fluid section.
1.
Loosen and remove the four front cover screws. Remove the
front cover.
2.
Stop the sprayer at the bottom of its stroke so that the piston is
in its lowest position.
3.
Perform the Pressure Relief Procedure and unplug the sprayer.
Before proceeding, follow the Pressure Relief
Procedure outlined previously in this manual.
Additionally, follow all other warnings to reduce
the risk of an injection injury, injury from moving
parts or electric shock. Always unplug the sprayer
before servicing!
4.
Unscrew the return hose assembly from the pump block. Remove
the retaining clip from the bottom of the foot valve housing.
Remove the siphon assembly.
5.
Tilt the sprayer back for easy access to the fluid section.
Pump block
Gasket
Valve stem
Cam base
assembly
Groove pin
SERVICING THE VALVES
The design of the fluid section allows
access to the foot valve and seat as well
as the outlet valve and seat without
completely disassembling the fluid
section. It is possible that the valves may
not seat properly because of debris stuck
in the foot valve seat or outlet valve seat.
Use the following instructions to clean
the valves and reverse or replace the
seats.
1.
Remove the pusher stem clip and
slide the pusher stem housing
from the foot valve housing.
2.
Using a wrench, loosen and
remove the foot valve housing
from the pump block.
3.
Clean out any debris in the foot
valve housing and examine the valve housing and seat. If the
seat is damaged, reverse or replace the seat.
4.
Using a 5/16" hex wrench, loosen and
remove the outlet valve retainer from
the piston rod.
Valve
handle
Always service the outlet
i
valve with the piston rod
attached to the pump. This
will prevent the piston
rod from rotating during
disassembly of the outlet
valve.
5.
Clean out any debris and examine the outlet valve housing and
seat. If the seat is damaged, reverse or replace the seat.
6.
Remove, clean, and inspect the outlet cage, crush washer, and
outlet valve ball. Replace if they are worn or damaged.
The outlet cage always must be used with the
i
crush washer. They are included together in the
repacking kit as assembly P/N 704-642.
7.
Reassemble the valves by reversing the steps above.
During reassembly of the outlet valve, apply one
i
drop of Loctite (included in the repacking kit) to
the threads of the outlet valve retainer before
threading it into the piston rod. Then, torque the
retainer to 144 in./lbs. (12 ft./lbs.).
MAINTENANCE
Pump
block
Bushing
Foot valve
seal
Inlet cage
Foot valve
ball
Foot valve
seat
PTFE
O-ring
Foot valve
O-ring
Pusher
stem
housing
Piston rod
Outlet cage
Crush
washer
Outlet valve
ball
Outlet valve
seat
Outlet valve
retainer
9