Graco Dispensit 802-20 [10/14] Periodic maintenance

PERIODIC MAINTENANCE

ASSEMBLY

Refer to the illustration above and the drawings in the back of this 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 spring can become a flying object if it escapes your control.

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

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

valve parts including seals and o-rings. Lightly lubricate the inside bore of the Cylinder Base Assembly (23) and

the outside of the Top Pinch-off Piston (15), Bottom Pinch-off Piston (7) and Dispense Piston (12). Check all

three pistons and the Backplate (18) for wear and if worn at the dispense tube contact areas 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 lubricated U-cup Seal (4) on the Bottom Pinch-off Piston (7).

2. Install the lubricated U-cup Seal (4) on the Top Pinch-off Piston (15).

3. Install the lubricated U-cup Seal (20) on the Dispense Piston (12).

4. Insert the Bumper (10) into the Backplate (18).

5. Assemble the Bottom Pinch-off Piston (7) and the Spring (6) with the Backplate (18). Use a tool to push the

spring down so that it fits under the backplate. Be sure the spring is centered under the backplate.

6. Assemble the Dispense Piston (12) and the Top Pinch-off Piston (15). This is easiest if you tilt the dispense

piston to slide it in place. Use care and a blunt tool to tuck the lips of the U-cup Seal (20) inward before

uniformly pushing it down into the valve sleeve.

7. Install the Dispense Piston/Top Pinch-off Piston Assembly (12 & 15) into the top cylinder in the Cylinder Base

Assembly (23), tucking the lip of the U-cup Seal (4) inward before uniformly pushing the piston assembly into

the cylinder bore. Add lubrication if needed.

Note: Position the upper ridge (where the #15 arrow is pointing in the illustration) of the Top Pinch-off Piston

(15) towards the top as shown for proper pinch-off action.

8. Install the Bottom Pinch-off Piston/Backplate Assembly (7 & 18) into the bottom cylinder in the Cylinder Base

Assembly (23), tucking the lip of the U-Cup Seal (4) inward before uniformly pushing it down into the cylinder

bore. Add lubrication if needed. Align the backplate holes and the top pinch-off piston so the parts fit

properly.

9. Hold the Backplate (18) in place with your thumb and install the two Srews (8) and two Spacers (19) in the

recessed holes in the backplate to hold it in place. Tighten the screws.

10. Install the Faceplate Assembly (17) using the Screws (9), and two Spacers (19). Tighten the screws.

11. Complete the assembly by remounting the valve and installing its dispense tube and needle.

12. Attach the material inlet line to the remote material supply or remount the syringe if so equipped.

13. Attach the air inlet line.

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

The valve is ready to be put back in service.