Graco HIGH-FLO 311211L - Manual (Page 12)

Operation
12 311211L
Operation
Pressure Relief Procedure
1. Engage trigger lock.
2. Air-Powered Pumps only: Close the bleed-type
master air valve.
Hydraulic-Powered Pumps only: Shut off the
hydraulic supply line valve (S) first, then the return
line valve (R).
3. Disengage the trigger lock.
4. Hold a metal part of the gun firmly to a grounded
metal pail. Trigger the gun to relieve pressure.
5. Engage the trigger lock.
6. Open all fluid drain valves in the system, having
waste containers ready to catch drainage. Leave the
drain valves open until you are ready to spray again.
7. If you suspect the spray tip or hose is clogged or
that pressure has not been fully relieved after follow-
ing the steps above, VERY SLOWLY loosen the tip
guard retaining nut or hose end coupling to relieve
pressure gradually, then loosen completely. Clear
hose or tip obstruction.
Flush Before Using Equipment
The equipment was tested with lightweight oil, which is
left in the fluid passages to protect parts. To avoid con-
taminating your fluid with oil, flush the equipment with a
compatible solvent before using the equipment. See
Flushing, page 13.
Trigger Lock
Always engage the trigger lock when you stop spraying
to prevent the gun from being triggered accidentally by
hand or if dropped or bumped.
Pump Operation
Stop the Pump at the Bottom of
Its Stroke
Relieve the pressure when you stop the pump for any
reason. Stop the pump on the downstroke, before the air
motor changes over.
CAUTION
Hydraulic-Powered Pumps only: When shutting down
the hydraulic system, always shut off the hydraulic
supply line shutoff valve (S) first, and then the return
line shutoff valve (R) to prevent overpressurizing the
motor or its seals. When starting the hydraulic sys-
tem, open the return line shutoff valve first.
• In a circulation system, the pump operates con-
tinuously until the power supply is shut off.
CAUTION
Do not allow the pump to run quickly for a long period
of time as this may damage the packings.
• In a direct-supply system, the pump starts
when the gun is opened, and stops when the
gun is closed.
• Perform a stall test periodically to ensure the
piston seal is in good working condition and
prevent system overpressurization:
• Close the fluid shutoff valve (D) closest to the
pump on the downstroke and be sure that the
pump stalls. Open the fluid shutoff valve to
restart the pump. Close the fluid shutoff valve
(D) closest to the pump on the upstroke and be
sure that the pump stalls.
CAUTION
Failure to stop the pump at the bottom of its stroke
allows fluid to dry on the piston rod, which can cause
damage to the throat packings when the pump is
restarted.
Hydraulic-Powered Pumps only: Always shut off the
supply line shutoff valve (S) first, and then the
return line shutoff valve (R). This is to prevent over-
pressurizing the motor or its seals.