Graco EcoQuip 300 Operation, Repair, And Parts page 26

Troubleshooting
Problem
Problem Problem
No abrasive flows from the
nozzle during blast mode.
No blast air flow when the blast
control is engaged. The water
pump cycles while the blast
control engaged.
No blast air flow when the blast
control is engaged. The water
pump does does not does not cycle while the not
blast control engaged.
26
Cause
Cause Cause
The pot does not have a sufficient
amount of abrasive.
The system is not properly set up.
There is an obstruction in the media
circuit.
The diaphragm valve is not working.
There is blockage inside the pot or
inside the abrasive hose between the
pot and the panel.
The blast regulator is not adjusted to
the correct pressure.
The tubing to the main air regulator is
not properly connected.
The blast air regulator is
malfunctioning.
The main air regulator is
malfunctioning.
The air supply is inadequate.
The Emergency Stop is engaged.
The electric blast control circuit is
malfunctioning.
The pneumatic blast control circuit is
malfunctioning.
Solution
Solution Solution
See Refilling the Pot with Abrasive, page
See Setting Up the Equipment, page
Make sure the pot pressure is properly set.
The pot pressure must be set 30 psi (2 bar,
0.2 MPa) above the blast pressure. Make
sure the selector valve is set to BLAST.
The abrasive ball valve must be open. The
abrasive metering valve must be at least 1/8
turn open.
See Flushing the Diaphragm Valve, page
See Repairing the Diaphragm Valve, page
Make sure the ball valve is closed, then
disconnect the cam-lock coupler. Open
the abrasive ball valve slightly and make
sure abrasive is flowing from the abrasive
hose. If not, follow the shut down procedure
(see Shutting Down, page
flush the pot and the media hose after draining
media and water.
Adjust the blast regulator to the desired
pressure while the blast control is engaged.
Confirm that the tubing from the blast
regulator to the main air regulator is intact.
See Hose Schematic, page
Replace the blast air regulator.
See Repairing the Main Air Regulator, page
30 .
Make sure the air inlet pressure gauge reads
100-125 psi (6.8–8.6 bar, 0.68–0.86 MPa). If
the gauge does not read 100–125 psi, check
the air compressor for proper setup.
Disengage the Emergency Stop..
Inspect the hose cable for damaged or
shorted wiring. Check the battery and control
panel connections. Make sure the DC power
source is 12V. Check the 3A fuse inside the
control panel, and replace it if necessary.
Check the current flow in the circuit. If current
exists, replace the relay.
See Pneumatic Blast Control Circuit, page
21.
14.
31.
32.
22). Thoroughly
42.
29.
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