Graco VPM 12, Instructions Manual

Page: 37 / 88

Operation
313875J 37
29. On the main run screen, verify the ratio check valve
button is not active.
NOTE: This verifies material dispenses through the
static mixer.
30. Place bucket under the end of the static mixer.
31. Press to begin dispensing then write down the
A (Red) and B (Blue) dispense pressures shown on
the ADM.
NOTE: During the dispense an off-ratio deviation may
be generated and that is ok.
32. Repeat the previous step until the “System Learning
New Setpoint” advisory turns off and the light tower
yellow lights turns from yellow to green.
33. Base purge the mixer to clear mixer of mixed mate-
rial:
NOTE: A base purge will dispense only the B (Blue)
material to push all mixed material out of the mixer.
Base purge settings are defined on the
System #2
screen, see page 61.
a. Press repeatedly to select Standby Mode
then press to accept.
b. Press .
c. Press to begin dispensing.
NOTE: Continue base purge until clean material comes
out of the end of the mixer.
d. When all mixed material is pushed out of the
mixer, press to stop dispensing.
34. Press repeatedly to select Shot Mode then
press to accept.
35. Press to activate the ratio check valves.
NOTE: Be ready to adjust ratio check valves immedi-
ately after performing the following step.
36. With buckets below the ratio check valves,
press to begin dispensing.
37. While dispensing, adjust the ratio check opening
adjustment screws until both material line pressures
are approximately equal to the pressures recorded
in step 31.
NOTE: If adjusting the ratio check opening screws after
a ratio check dispense, the pressure difference due to
the adjustment will not be shown until the next dispense.
NOTE: After the ratio check dispense pressures are
properly adjusted a ratio check dispense can be per-
formed. The ratio check dispense should be at least 10
seconds.
38. If the pressures are correctly adjusted prior to com-
pleting the shot, press to stop dispensing.
39. If the pressures were not correctly adjusted prior to
the shot finishing, go to step 36 to repeat.
Ratio Check
NOTE: In the following steps, the weight of the dis-
pensed materials is used to calibrate the flow meters.
This works regardless of whether the selected dispense
mode is weight or volume.
40. With active and with pre-weighed buckets
below the ratio check valves, press to begin
dispensing a ratio check dispense.