Graco EcoQuip 2 EQs Instructions Manual page 32

Troubleshooting
Problem
No blast air flow when
the blast control
switch (B) is engaged.
The water pump does
not cycle while the
blast control switch is
engaged.
32
Cause
The emergency stop
(Q) is engaged.
The air supply is
inadequate.
The electric blast
control circuit is
malfunctioning.
The pneumatic blast
control circuit is
malfunctioning.
Disengage the emergency stop (Q).
Make sure the air compressor is capable of supplying the minimum
air flow requirements for your system. See Technical
Specifications, page 66, for more information. Make 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.
Ensure proper 12V DC supply is connected, and at full charge.
Inspect cable for damaged or 'open' wiring. Check blast control
fuse and replace if necessary. Check for continuity through
connectors on the control box and all external cables. Check
continuity though 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 and twin-line by disconnecting the yellow
tube at the enclosure male quick disconnect and engage the
control switch. If no air comes from the fitting, check the pneumatic
blast control filter. If the filter is clean, check for signal air at the
blast control switch. Replace the pneumatic blast control switch if
signal air does not pass through the valve when the handle is
depressed. If the switch is functioning, make sure the yellow tubing
inside the control box is properly connected and is clear of
obstructions. If the tubing is clean, replace the 4-way solenoid
valve.
Solution
3A7467C