Graco PR70 Repair And Parts Manual page 30

Repair
The following procedure is the same for Fixed and
Variable Ratio bases, except where noted. See F
7 and F . 8 for part references. See Kits on
IG
page 77 for kit numbers.
NOTE: The HydraCheck kit is intended to be used with
low viscosity materials to minimize splashing. It is not
intended to be used as a timer or flow control device.
Prepare Machine for Kit Installation
1. Navigate to the Manual screen.
2. Press the Retract Piston Command button.
3. Relieve system pressure. See Pressure Relief Pro-
cedure on page 14.
4. Remove shroud screws (2202, 2409). See F
on page 44 and F
IG
5. Remove the shroud (117, 214). See F
page 42 and F . 21 on page 48.
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Install HydraCheck Shock
Be sure that system pressure is relieved and dis-
abled before proceeding.
6. Install shock absorber (200a) through the opening in
the pump sub-assembly (203) with the groove for
the snap ring on the back of the pump assembly.
The shock absorber can be inserted through the
front or the back of the pump sub-assembly.
7. Install shock snap ring (included with shock, not
shown) onto the shock absorber (200a) in the
groove farthest from the pump sub-assembly.
8. Install set screw (200b) and torque to 85 in-lb
(9.6 N•m).
30
. 21 on page 48.
. 16 on
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Install Adjustment Screw/Cap
.
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9. On Variable Ratio models, loosely install hex
nut (200d) and adjustment screw (200c) onto the
variable ratio drive block (AA).
On Fixed Ratio models, loosely install hex
nut (100b) and adjustment cap (100d) onto the air
cylinder shaft (420).
Adjust the Adjustment Screw/Cap
. 17
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10. Push the drive block (104, AA) forward until resis-
tance is felt when it engages the cylinder. Make sure
the resistance is not due to shock absorber (200a)
contact with the adjustment screw (200c) or adjust-
ment cap (100d).
11. Adjust the adjustment screw or adjustment cap until
it contacts the shock absorber.
12. On Variable Ratio models, hold the adjustment
screw (200c) in place and tighten the hex nut (200d)
against the drive block (AA).
On Fixed Ratio models, hold the adjustment
cap (100d) in place and tighten the hex nut (100b)
against the adjustment cap.
Prepare Machine for Operation
13. Lift the system air pressure relief switch to enable
system pressure. It is the yellow tab at the left, rear
of the machine.
Adjust Shock Resistance
14. Execute a shot to see how the shock absorber
affects the speed of the drive block (104, AA).
15. The shock absorber has a numeric scale on one
side. Rotate the knob with the scale to a higher
value for more resistance. Rotate the knob to a
lower value for less resistance.
16. Repeat these steps until the desired resistance is
achieved.
312760Y