Graco HFRL, Setup And Operation Manual

Page: 40 / 142

Operation
40 3A2175Z
Pressure Relief Procedure
1. Shut off feed pumps and agitator, if used.
2. Turn PRESSURE RELIEF/DISPENSE valves (SA,
SB) to PRESSURE RELIEF/CIRCULATION .
Route fluid to waste containers or supply tanks.
Ensure gauges drop to 0.
3. For models with an dispense valve with a safety
lock, engage gun safety lock.
4. Relieve pressure in dispense valve. See dispense
valve manual.
Flushing
• Flush out old fluid with new fluid, or flush out old
fluid with a compatible solvent before introducing
new fluid.
• Use the lowest possible pressure when flushing.
• All fluid components are compatible with common
solvents. Use only moisture-free solvents. See
Accessories on page 136 for list of wetted compo -
nents to verify compatibility of solvent with wetted
materials. See solvent manufacturers information
for material compatibility.
• To flush feed hoses, pumps, and heaters separately
from heated hoses, set PRESSURE RELIEF/DIS -
PENSE valves (SA, SB) to PRESSURE RELIEF/CIR -
CULATION . Flush through bleed lines (N).
• To flush entire system, circulate through gun fluid
manifold (with manifold removed from gun).
• To prevent moisture from reacting with isocyanate,
always leave the system dry or filled with a mois -
ture-free plasticizer or oil. Do not use water. See
Important Two-Component Material Information
on page 14.
• Solvent pails used when flushing : follow your local
code. Use only metal pails, which are conductive,
placed on a grounded surface. Do not place pail on
a nonconductive surface, such as paper or card -
board, which interrupts grounding continuity.
• To maintain grounding continuity when flushing or
relieving pressure, hold a metal part of dispense
gun firmly to the side of a grounded metal pail, then
trigger gun.
NOTICE
The fittings on the pressure relief hoses are zinc
plated carbon steel. The hoses are cured with sul -
fur. Check your materials for compatibility with zinc
plating and sulfur before reusing any material that
passed through them, as it may inhibit curing.
Flush equipment only in a well-ventilated area. Do not
dispense flammable fluids. Do not turn on heaters
while flushing with flammable solvents.
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SA
SB
SA
SB
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N
N