Operating Manual Troubleshooting
4/1/99
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d)
An inlet valve ball and/or a leaking seat gasket that does not properly seat will
permit some of the proportioned material to flow back towards the supply drum.
When this happens, the proportioning pump will not pump the proper volume of
material during the discharged stroke and an off-ratio condition will result. This
malfunction will evidence itself identically to Cavitation, perhaps somewhat less
severe however.
4.
REVERSING MALFUNCTION- For the proportioning pumps to change direction or
reverse, the Activator plate must contact the rocker arm to activate the reversing
switch. Failure of the activator plate to make proper contact is usually caused by
something physical such as a bent or loose activator plate.
Should the above not be the cause, the problem is likely to be a result of the pump
piston packing retaining bolt having loosened. This would cause the piston to contact
the inner face of the pump inlet flange before the activator plate contacts the rocker
arm. To resolve this, shut down the unit and disassemble the appropriate pump for
repair.
When the directional valve fails to shift the activator plate will have passed the
rocker arm and not reversed. When this happens, the first thing to do is to relocate
the activator plate so that it is situated between the arms of the rocker arm as follows:
a)
Determine in which direction the plate must move: this is predicated upon which
stroke is overrun.
b)
Go to the hydraulic manifold and
locate the manual operator
centered in the end of the housing
of the coil on the same side of the
machine toward which the
activator plate must go. For
example: If the plate over ran to
the left and requires moving to the
right toward the Resin pump go to
coil on the Resin side.
Figure 25. Hydraulic Manifold
With the gun (or coupling block) open, the main circuit breaker and motor
control ON, and the pump switch OFF, push in the manual operator (a 3/16
Allen wrench is ideal for this) and hold it in until the activator plate is
approximately centered. Release it and close the gun or coupling block.
If the spool seemed to move freely when pushed the cause of the overrun was
probably an electrical problem. Turn off the motor and place the pump switch in
the NORMAL position. Push in each end of the rocker arm, listen for the
shifting of the spool, and note the direction indicators light as appropriate. If the
spool does not shift, or if the lights do not light, there is an electrical problem
with the reversing switch, directional valve coil, or pump switch.
Should the spool hang up or be hard to push, it is likely that there is a
mechanical problem within the directional valve, which will necessitate shutting
down the unit and disassembling the directional valve for service.
5.
OVER-PRESSURE PROTECTION- Each proportioning pump contains a pressure
switch set to 2200 psi / 3700 psi. On reaching this pressure, the switch will
automatically remove power from the directional valve causing the pumps to stall.
When the power is removed both directional indicator lights will go off which is the
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