ASPHAL
T OPERA
TIONS
56 Asphalt Operations
Spray Bar Suck Back
Refer to Figure 74a or 74b for the following proce-
dures.
1. Park the Distributor and set the parking brake.
The Engine must be running and the optional
transmission PTO must be engaged.
2. Turn the MASTER SPRAY switch OFF.
3. Turn the cab POWER switch ON and turn the rear
EMERGENCY STOP ON.
4
. At the rear of the distributor, set or confirm the
following:
• Return valve open
• Tank Valve closed
• Master hand spray valve closed
• Transfer line suck back valve closed
• Transfer line valve closed
• Flush valve closed
• Load and transfer line caps are in place
and secured
5. Increase truck RPM over 1000 RPM
6. Go to suck back on the screen
7. Move pump to auto if not already there (200 GPM
default)
8. Tap start pump button
9. Raise spray bar and fold wings
10.
Let pump suck back for a sufficient period of
time to allow all the product to be pulled from
the spray bar and circulating system as defined
by the pump (noise/load). Do not open any
spray valve or air into the system at this time.
1
1. When confident that the product pump is not
pulling any material from the circulating system,
turn on the wash down pump (if equipped) or
open the flush valve on the side of the load line
to introduce release agent into the system.
NOTE: Without a wash down pump it will be
a calculated guess as to how much release
agent is going into the system due to the nature
of the condition of the wash down system (this
may take extra time). With the wash down pump
running, open the flush valve for a period of
time (20 to 30 seconds, depending on material
in the circulating system) to allow release agent
to migrate into the strainer box and over to the
asphalt pump.
NOTE: The pump can be stopped and the auto-mat-
ic tank valve can be closed immediately at any time
during operation by turning the EMERGENCY STOP
switch OFF.
For asphalts like AC it is recommended that this
procedure be repeated a second time, after which
adding solvent such as diesel fuel through each
bleeder will quickly flush the spray bar.
If not equipped with an electric pump, it is helpful to
pour some diesel fuel down the fill line after all op
-
erations are completed. The diesel fuel will remain
in the pump overnight to keep the pump free for the
next morning’s operation.
E
nsure that the self flush valve is closed at the
end of this function, or before loading or circulating
asphalt to eliminate chances of inducing asphalt into
the self flush fuel tank.
Figure 73 - Suck Back Operation Mode
12. At this time while the wash down pump is running
and suck back is in auto, turn the dial approx-
imately ¾ turn clockwise then change the pump
from auto to manual and start the pump again.
Adjust the pump GPM to around 60 GPM for
another 10 seconds then turn the pump dial
counterclockwise to the 0 GPM position for
approximately another 10 seconds.
1
3. Turn the flush valve to the off position, shut off
the wash down pump then hit the power button
to turn off the system.
