Graco Dispensit 792-20 [10/14] Periodic maintenance

PERIODIC MAINTENANCE

ASSEMBLY

Refer to the illustration above and to the drawings in the back of the manual for your exact model.

Caution: Make sure you have your safety glasses on and that the valve is pointed away from you

and others. The Springs (10) can become flying objects if they escape your control.

Note: Clean all valve parts with an appropriate solvent prior to reassembly. Always install new, lubricated

seals when assembling the valve. Use Krytox 203GPL (part number 84/0200-K3/11) for lubricating valve

parts including seals. Lightly lubricate the inside bore of the Cylinder Base Assembly (6) and the outside

of the Pinch-off Piston (11). Check the Pinch-off Piston (11) and Faceplate (15) for wear at the material

hose contact area and if worn or distorted secure replacements before proceeding.

Note: Use caution as you install new U-cup seals so that they are not pinched or torn. Do this by making

sure they are lubricated, and by tucking the lips of the seal inward before uniformly pushing them into

position.

Note what direction the old seals face as you remove them. Make sure the new seals face in the

proper direction when you install them. Consult the drawings for orientation to be sure.

1. Install the U-cup Seal (7) on the Pinch-off Piston (11).

2. Insert the Springs (10) into the Pinch-off Piston (11).

3. Set the Pinch-off Piston assembly on top of the Cylinder Base Assembly (6). Use a blunt tool to

carefully tuck the U-cup Seal (7) in while easing the piston into the Cylinder Base Assembly (6). See

drawings for piston orientation.

4. Compress the Springs (10) with a small screwdriver or other tool to assist in placing the Backplate (1)

in position. Be sure the Springs (10) are centered under the Backplate (1).

5. Insert two of the Tie Rods (4) and install two Screws (2) and tighten them to tie the Backplate (1)

down.

6. Place the Faceplate (15) onto the Backplate (1). See drawing for orientation. Slide the two Spacers

(21) into position and install two Screws (3) through the faceplate and spacers and tighten them.

7. Slide the Top Tube Adapter (12) hexagon end up onto the new Material Hose (16).

8. Slide Bottom Tube Adapter (17) onto the new Material Hose (16) until the hose is flush with the end of

the adapter.

9. Depending on the valve configuration, insert the steel end of the Hose Adapter (19) or Needle

Assembly (18) into the end of the Material Hose (16) and tighten onto the Bottom Tube Adapter (17).

10. Slide the Top Tube Adapter/Material Hose/Bottom Tube Adapter Assembly (12, 16 & 17) through the

side of the valve.

11. Gently tighten the upper and lower Knobs (13).

12. Mount the valve to its point of use.

13. Connect any downstream fittings that you disconnected from the Hose Adapter (19).

14. Connect the material reservoir and pressurize it.

15. Connect the air supply line to the valve controller.

Perform the Dry System Checkout, Material Loading and Wet System Checkout.

The valve is ready to be put back in service.