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781Mini Series Spray Valve
14
Service (continued)
CAUTION
Before any component change or service activity, relieve air pressure from the fluid reservoirs.
CAUTION
After a needle and nozzle are used together, do not replace either component with a different needle or nozzle.
When replacing a needle, also replace the corresponding nozzle. Failure to replace needles and nozzles together
can create a poor seal, causing leakage.
Replacing a Valve Component (Full Disassembly
and Reassembly)
Disassemble the Valve
1. Make a note of the current stroke setting number.
2. Turn the stroke control knob counterclockwise to fully open.
3. Remove the stroke control assembly.
4. Remove the spring from air cylinder body.
5. Use snap ring pliers to remove the piston retaining ring.
WARNING
The needle is very sharp. Handle it cautiously to prevent injury.
CAUTION
Do not grasp the needle with pliers. Doing so can damage the
needle.
6. Carefully pull the needle-and-piston assembly out of the air
cylinder body.
NOTES:
• The needle-and-piston assembly cannot be disassembled.
• The stroke control and piston O-rings are the same size.
7. Remove the U-cup seal from the inside of the fluid body only if
it needs to be replaced.
8. Turn the QR clasp thumbscrew counterclockwise to disengage
the QR clasp and then remove the clasp.
9. Remove the double-stacked O-rings from inside the fluid
body (these O-rings typically remain in the fluid body after it is
removed).
10. Remove the fluid inlet fitting and nozzle air fitting.
11. Remove the air cap retaining nut and then remove the air cap
and the nozzle components.
Stroke control assembly
with O-ring
Air cylinder body
Needle-and-piston
assembly
Piston O-ring
Spring
Piston retaining
ring
Air cap
Air cap
retaining nut
Fluid body
Fluid inlet
fitting
Nozzle air
fitting
Double-stacked
O-rings
U-cup seal
Nozzle (PEEK nozzle
shown)
Nozzle O-ring
Nozzle dispersion ring
