Graco EcoQuip 2 EQs Instructions Manual page 34

Troubleshooting
Problem
The blast control
switch (B) is not
engaged, but blasting
occurs.
While the blast control
switch (B) is engaged,
the blast air flow is
fluctuating.
34
Cause
The air supply is
inadequate.
The main air regulator
is malfunctioning or is
stuck open.
The electric blast
control circuit is
malfunctioning.
The pneumatic blast
control circuit is
malfunctioning.
The supply air
pressure is fluctuating.
The main air regulator
is malfunctioning or is
stuck open.
The electric blast
control circuit is
malfunctioning.
The pneumatic blast
control circuit is
malfunctioning.
Make sure the air compressor is capable of supplying the minimum
air flow requirements for your system. See Technical
Specifications, page 66. Makes sure the air inlet pressure gauge
reads 100-175 psi (6,8-12 bar, 0.68-1.2 MPa). If the gauge does
not read 100-175 psi, check the air compressor for proper setup.
Disassemble the main air regulator and check for obstructions.
Replace or repair parts as necessary. See Enclosure Box Parts,
page 50.
Unplug the hose cable at the control box. If the blast stops, inspect
the hose cable for shortened wiring. Check continuity through the
electric blast control switch (B) (the switch is normally open).
Check for continuity across connectors of the recessed plugs on
the control box (there should be no continuity). If all above items
are functional, replace the 4-way solenoid valve.
Engage the emergency stop (Q). If blasting stops, check the blast
control switch (B) by disconnecting the yellow tube at the
enclosure male quick disconnect. There should be no signal air
unless you engage the control switch. If the switch is functioning,
remove the exhaust mufflers from the 4-way and check for debris,
clean ports, and replace the mufflers if necessary. If all above
items are functional, replace the 4-way solenoid valve.
Make sure the compressor meets minimum flow requirements and
is operating properly. See Technical Specifications, page 66, for
more information on flow requirements.
Disassemble the main air regulator and check for obstructions.
Replace or repair parts as necessary. See Enclosure Box Parts,
page 50.
Inspect the hose cable for damaged or shorted partially open
wiring. Check the blast control fuse and replace if necessary.
Check for loose wire connections on the recessed plugs on the
control box (P) and all external cables. Check continuity through
the electric blast control switch (B) (the switch is normally open). If
all above items are functional, replace the 4-way solenoid valve.
Actuate the blast control switch (B) and check for proper spool
valve actuation in the 4-way valve. If no actuation occurs, check
the blast control switch by disconnecting the yellow tube at the
enclosure male quick disconnect and engage the control switch. If
only a little air comes from the fitting, check the twin-line hose for
damage or crimping and check the pneumatic blast control filter. If
the twin-line and filter are clean, replace the pneumatic blast
control switch. If the switch is functioning, make sure the yellow
tubing inside the control box is properly connected and clear any
obstructions. If all above items are functional, replace the 4-way
solenoid valve.
Solution
3A7467C