User's Manual

Maintenance
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Pour Nozzle Maintenance
With proper maintenance, the L-Head is capable of per-
forming thousands of pours without the need for remov-
ing and cleaning the pour nozzle. However, the use of
fast-reacting chemicals will require more frequent pour
nozzle removal and cleaning. The faster the chemical
reaction, the more frequent the need to clean the pour
nozzle. This is due to hardening of the chemicals before
the cleanout plunger can clean the bore. A sticking clea-
nout plunger is a good indication that the pour nozzle
must be cleaned. Use the following maintenance prac-
tices to help minimize cleanout plunger sticking:
Cleanout Plunger Lubrication
If the MixHead is to be left idle for any period of time, the
cleanout plunger should be lubricated before leaving.
1. Retract the cleanout plunger to the open/pour posi-
tion.
2. Run a fine-grade wire brush up and down the clea-
nout bore to remove any loose foam.
3. Bring the cleanout plunger to the closed position,
and completely submerge the pour nozzle in a cup
of mesamoll plasticizer.
4. Cycle the cleanout plunger.
5. The mesamoll will be sucked up into the MixHead,
providing the lubrication between the cleanout
plunger and the bore it rides in.
6. Cycle the cleanout plunger several more times to
ensure that all of the remaining foam is removed,
and then leave the cleanout plunger in the
open/pour position.
Cleanout Plunger Retract Routine
During operation, periodic lubrication with mesamoll
may be all that is required to prevent sticking. However,
in cases where sticking is a continual problem, the clea-
nout plunger retract routine may be utilized.
In the retract routine, the cleanout plunger is retracted
as soon as it is permissible after each shot, to ensure
that the scraper seal has a chance to remove the foam
from the cleanout plunger while the foam is still wet.
Contact Graco technical service to learn more about the
cleanout plunger retract routine. Some modifications to
the software timing are required to incorporate this pro-
cedure.