Proportioning System - Graco Reactor H-25 Series Repair And Parts Manual

Troubleshooting

Proportioning System

Before performing any troubleshooting procedures:
1. Relieve the pressure. See Pressure Relief
Procedure, page 26.
PROBLEM
Proportioning pump does not hold
pressure when stalled.
Material imbalance. See
Pressure/Material Imbalance, page
24.
22
2. Turn main power OFF
3. Allow equipment to cool.
Problems
Try the recommended solutions in the order given for
each problem, to avoid unnecessary repairs. Also,
determine that all circuit breakers, switches, and
controls are properly set and wiring is correct before
assuming there is a problem.
CAUSE
Pump piston or intake valve leaking.
Restriction at the gun.
Inadequate flow from pump;
cavitation.
Pressure relief/circulation valve
leaking back to supply.
.
SOLUTION
1. Observe gauges to determine
which pump is losing pressure.
2. Determine in which direction the
pump has stalled by observing
which directional valve indicator
light is on. See Table 2, page 24
to isolate the problem.
3. Repair the valve; see your pump
manual.
Clean the gun; see your separate
gun manual.
Increase fluid supply to proportioning
pump:
• Use 2:1 supply pump
• Use minimum 3/4 in. (19 mm) ID
supply hose, as short as practical
Fluid is too thick. Consult your
material supplier for the
recommended fluid temperature to
maintain a viscosity of 250 to 1500
centipoise.
Clean inlet strainer screen, Inlet
Fluid Strainer Screen, page 43.
Worn pump inlet valve ball/seat or
gasket. Replace, see your pump
manual.
Remove return line and determine if
flow is present while in SPRAY
mode.
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