Graco Aerobotix RC50 Instructions Manual page 33

NOTICE
Relieving tank pressure may introduce moist air into
the system causing crystallization and damage to the
machine.
The pumps must never be run dry. If the metering
pump is not properly supplied with fluid and pressure
during operation, cavitation will result. This will dam-
age the pump and will lead to an "off ratio" condition.
To ensure proper supply of material to the dispense gun,
the machine includes temperature conditioned and
pressurized day tanks.
Temperature conditioning is accomplished by circulating
the chemicals through a heat exchanger in the inlet sup-
ply line and heater in the high pressure supply line. The
operator-selected temperature is maintained by the pro-
gram.
To assure adequate chemical pressure at the inlet to the
metering pump, the tank must be pressurized with dry
air to the specification listed in the table at the beginning
of the Settings section on page 45.
The fluid level in the tank must be manually maintained
between 60% to 90% full to assure proper temperature
and aeration control, unless the optional Auto-Fill sys-
tem is installed. A tank fluid level sight gauge (MH) is
also provided.
Should the pressure in a tank rise excessively while the
tank is refilling, an operator adjustable pressure relief
valve is provided to assist the regulator in bleeding the
pressure. The recommended set point for this valve is
listed in the table at the beginning of the Settings sec-
tion on page 45.
Level Sensor
A sensitivity adjustment is provided for the level sensors
to compensate for various liquid properties. Turn clock-
wise to increase sensitivity and counterclockwise to
decrease sensitivity.
313813A
Metering Pump Inlet Filter
NOTICE
The metering pump inlet filter prevents particulate mat-
ter from damaging the precision metering pumps. The
filter element is a basket type and should it become
clogged, it will cause cavitation of the pump resulting in
damage to the pump. Therefore, it is necessary that the
filter be properly serviced at all times. See Mainte-
nance section on page 54.
Air Pressure System
The minimum recommended supplied dry air pres-
sure is listed in the table at the beginning of the
Settings section on page 45.
The air supplied to the machine must be dry. To remove
excess moisture and particulate matter from the shop
air, a water separator is provided. For the day tanks only,
a desiccant air dryer is provided to charge the day tanks.
To prevent contamination of the air system by a reaction
of the iso fumes with the poly fumes, the systems are
isolated by means of separate check valves.
Adjust Day Tank Settings
See Day Tank Settings section on page 48 for more
information.
Operation
33