ITW Dynatec DYNAMINI Operation And Service Manual page 48

ITW Dynatec c. 2004
DYNAMINI ASU Manual #20-25
Problem
Pump Quick-Strokes in
Both Directions
Loosen
set screw
Open
drain
Inlet check valve
Outlet
check valve
Pump Quick-Strokes
on the Forward-Stroke
Only (shaft moving
into pump body)
Possible Cause
1. No adhesive in hopper.
2. Adhesive too cold to flow
into pump.
3. Adhesive used is too
viscous.
4. Pump needs priming.
5. Problem with pump shaft
piston.
6. Large opening in system
downstream of pump.
1. Inlet check valve blocked
open.
Solution
1. Verify that hopper has an adequate
level of hot melt adhesive.
2. Check ready temperature to
make sure there has been enough
time for the adhesive to rise to the
hopper setpoint temperature.
3. Verify that adhesive selection and
hopper setpoint temperature are
compatible and that both are
appropriate for your application.
4. Prime the pump by first lowering the
air pressure, then letting the pump
cycle very slowly until primed.
5. Remove the shaft and piston from
the pump. See Chapter 8 for dis-
assembly/ assembly procedures.
Verify that piston diameter is
correct: 19.63mm to19.66mm
(0.773" to 0.774") and that piston is
tightly assembled to end of shaft.
6. Inspect system for open filter drain,
disconnected or ruptured hose, or
disconnected head. Repair as
necessary.
1. Clean inlet check valve. This may
be possible without removing the
pump by cleaning debris through
the pump inlet hole at bottom of
hopper.
Page 7-11
Revised 1/05