Graco EcoQuip 300 Operation, Repair, And Parts page 24

Troubleshooting
Problem
Problem Problem
The blast control is not
engaged but blasting still
occurs.
The blast spray pattern is
irregular.
24
Cause
Cause Cause
The pneumatic blast control circuit
is malfunctioning.
The main air regulator is stuck
open.
The blast control tubing is not
connected properly.
Electric blast control circuit is
malfunctioning.
Pneumatic blast control circuit is
malfunctioning.
Incorrect abrasive is being used.
The pot does not have a sufficient
amount of abrasive.
The pot pressure setting is
incorrect.
The Auto-Vent valve does not vent
air when the pot is filled.
The diaphragm valve is
malfunctioning.
There is blockage inside the pot or
inside the abrasive hose between
the pot and the panel.
Solution
Solution Solution
See Pneumatic Blast Control Circuit,
page 27.
See Repairing the Main Air Regulator,
page 28 (EQ600 – Kit 17C131, EQ300
– Kit 17C129).
Ensure air tubing is routed and connected
properly. See Hose Schematic, page
Inspect hose cable for damaged or
shorted wiring. Check battery and control
panel connections. Ensure DC power
source is 12V. Check 3A fuse inside
control panel and replace it if necessary.
Check current flow in circuit, if current
exists, replace relay (EQ5179).
See Pneumatic Blast Control Circuit,
page 27.
Use the correct abrasive. See
Metering Valve Settings, page
Refill the pot with abrasive. See
Refilling the Pot with Abrasive, page
Perform the pressure relief procedure
(see Pressure Relief Procedure, page 8
and reset pot pressure (see
Setting Up the Equipment, page
Make sure the Auto-Vent valve
is working. Perform the Auto-
Vent cleaning procedure (see
Cleaning the Auto-Vent Valve, page
Perform the diaphragm
flush procedure (see
Flushing the Diaphragm Valve, page
If flushing does not solve problem, 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 form the abrasive
hose. If not, follow the shut down
procedure (see Shutting Down, page
Thoroughly flush the pot and the media
hose after draining media and water.
39.
16.
18.
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11).
31).
29).
30.
19).
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