Repair; Service Screen Screw; Remove Check Valve - Graco GX-8 Operation, Parts, Service, Repair

Repair

Shutdown proportioner and allow chemicals
to cool before servicing gun.

Service Screen Screw

To avoid static sparking that may result in fire
or explosion, ensure all equipment in flushing
procedure is grounded. Do not flush on or
near foamed or coated surfaces.
1. Flush gun see Clean Spray Gun Proce-
dure, page 15.
2. Unthread screen screw from gun block.
3. Remove screen screw retainer before
removing screen.
4. Remove screen from screen screw. Soak in
gun cleaner or replace if clogged or dirty.
5. Clean screen screw cavity. If any particles
are visible, clean with clean out drills and
flush with gun cleaner.
Any material left in cavity on downstream
side of screen will clog mixing module.
6. Inspect screen screw seal for damage.
Replace if necessary.
7. Reinstall screen screw in gun block. Ensure
it is tight.
8. Flush gun with mixing module removed.
311338B

Remove Check Valve

To avoid static sparking that may result in fire
or explosion, ensure all equipment in flushing
procedure is grounded. Do not flush on or
near foamed or coated surfaces.
Check valves are located in cavities of gun
block under each coupling block gasket. Check
valves are triangular pieces with a spring insert-
ed in one end. The isocyanate valve is notched
for easy identification.
To remove check valve:
1. Clean gun (see Clean Spray Gun Proce-
dure, page 15).
2. Use check valve seal removal/cleaning tool
to remove gaskets from recesses in cou-
pling block. Inspect gaskets for damage
and replace if necessary.
3. Remove check valves. If valve does not
come out easily, insert machined end of
removal/cleaning tool over valve and rotate
it while extracting valve.
4. Clean valves and springs with gun cleaner.
Inspect for damage and replace if neces-
sary.
5. Inspect each check valve cavity. Use clean-
ing tool to remove any visible particles. Use
gun cleaner to flush thoroughly.
6. Insert each check valve into its cavity
spring end first. Ensure check valve is ori-
ented correctly. Isocyanate valve is notched
for easy identification.
7. Install coupling block gaskets.
Repair
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