Proportioning System - Graco Reactor H-VR Repair And Parts Manual

Troubleshooting

Proportioning System

Before performing any troubleshooting procedures:
1. Relieve pressure, page 28.
PROBLEM
Proportioning pump does not hold
pressure when stalled.
Material imbalance. See Pres-
sure/Material Imbalance, page 26.
24
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 con-
trols are properly set and wiring is correct before assum-
ing there is a problem.
CAUSE
Pump piston or intake valve leaking.
Restriction at the gun.
Inadequate flow from pump; cavita-
tion.
Pressure relief/circulation valve leak-
ing back to supply.
Spraying at a ratio other than 1:1 can
cause pressure imbalance.
.
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 26
to isolate the problem.
3. Repair the valve; see pump man-
ual 313485.
Clean the gun; see Pumps Do Not
Reverse Direction, page 27.
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 mate-
rial supplier for the recommended
fluid temperature to maintain a vis-
cosity of 250 to 1500 centipoise.
Worn pump inlet valve ball/seat or
gasket. Replace; see pump manual
313485.
Remove return line and determine if
flow is present while in SPRAY
mode.
Size hoses and mix chamber appro-
priately.
313540L