Graco SuperCat 232721, Instructions-Parts List Manual

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Troubleshooting
WARNING
INJECTION HAZARD
This system can produce very high fluid
pressure. To reduce the risk of a serious
injury:
Follow the Pressure Relief Procedure on page
21 before checking or servicing the equipment.
Use very low air pressure to operate the pump
when troubleshooting.
WARNING
MOVING PARTS HAZARD
To reduce the risk of injuring or amputat-
ing hands, fingers, or other body parts,
never place your hands, body or tools
inside the safety panels while the unit is
operating.
Pump Lowers
Because the pumps are mechanically linked, the action
of one pump can affect the readings of the second
pump. Therefore, the key to successful troubleshooting
is to isolate the problem.
For example: if the secondary pump pressure gauge
reading is low and sluggish during the pump change-
over, the most likely problem is a binding primary
pump. To isolate the problem:
Isolating the Primary Pump
1. Follow the Pressure Relief Procedure on page
21.
2. Open the fluid drain valves (204).
3. Set the Premier pump air regulator (C) to the
lowest setting and make sure the pump air valve is
open.
4. Press and hold the Premier pump key (PK).
Increase the air regulator (C) setting until the pump
just begins to move. Notice the position of the
secondary pump (312 ). Release the Premier
pump key so that the secondary pump rod is at its
lowest position when the pump stops.
5. With the main air valve closed, remove the screws
(469) and guard (424) from the side of the propor-
tioner.
6. Unscrew the connecting rod nut (361) from the
secondary pump (312 ). Now you can verify the
operation of the primary pump (311 ) alone.
7. Reinstall the guard (424) on the proportioner.
8. Turn on the main air valve, press the Premier
pump key (PK), and carefully increase the Premier
pump air pressure.
9. Open and close the fluid drain valves (204) and
check for pump stalling on both the up and down
strokes.
10. Check for rapid gauge (207) response during the
pump changeover.
11. When the operation of the isolated pump has been
verified, turn the Premier pump air regulator setting
to zero and follow the
Pressure Relief Proce-
dure .
12. Turn off the main air valve.
13. Reconnect the pump connecting rod nut (361).
Isolating the Secondary Pump
14. With the fluid drain valves (204) still open, set the
Premier pump air regulator (C) to the lowest
setting and open the main air valve.
15. Press and hold the Premier pump key (PK).
Increase the air regulator (C) setting until the pump
just begins to move. Notice the position of the
primary pump (311 ). Release the Premier pump
key so that the primary pump rod is at its lowest
position when the pump stops.
16. With the main air valve closed, remove the screws
(469) and guards (446) from the side of the propor-
tioner.
17. Unscrew the connecting rod nut (361) from the
primary pump (311 ).
18. Now you can verify the operation of the secondary
pump alone. Follow steps 7–13, above.