Graco EcoQuip 2 EQs Instructions Manual page 31

Problem
The blast hose recoils
heavily when the blast
control switch (B) is
engaged. Large slugs
of abrasive and water
are ejected from
nozzle.
The pot pressure relief
valve is discharging
water.
No blast air flow when
the blast control
switch (B) is engaged.
The water pump does
cycle while the blast
control switch is
engaged.
3A7467C
Cause
The abrasive ball valve
was left open during
shut down.
The abrasive ball valve
is worn.
The pinch hose is
worn.
The water pressure
regulator is
malfunctioning.
The pressure relief
valve has failed.
The adjustable blast
regulator is not
adjusted to the correct
pressure.
The tubing to the main
air regulator is not
properly connected or
there are air leaks in
the fittings or tubing.
The adjustable blast air
regulator is
malfunctioning.
The main air regulator
is malfunctioning.
See Shutdown, page 26, step 2.
With the pot pressurized and the abrasive ball valve closed,
engage the blast control switch (B) and check to make sure the
pump is stalled. If the pump rod is creeping, replace the abrasive
ball valve (M).
With the pot pressurized and the abrasive ball valve open, check to
make sure the pump is stalled. If the pump rod is creeping, replace
the pinch hose. See Replace the Pinch Hose, page 38.
Adjust the water pressure regulator to 185 psi (12.75 bar, 1.275
MPa). If this adjustment is not possible, service the water pressure
regulator. Refer to your regulator manual. See Related Manuals,
page 3.
Replace the pressure relief valve if weeping occurs at or below 185
psi (12.75 bar, 1.275 MPa).
Adjust the blast regulator to the desired pressure while the blast
control is engaged.
See the Tubing Schematic, page 61. Check for leaks at
connection points.
Clean or replace the adjustable blast air regulator.
Disassemble the main air regulator and inspect components.
Replace or repair parts as necessary. See Enclosure Box Parts,
page 50.
Troubleshooting
Solution
31