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Operation
SP 500 / 750-15 / 750-18 / 1000 / 1250 Operation Manual
Cleanout
You will often have to wait for the “balance load” of con-
crete to arrive. This is usually 1 or 2 yards that the con-
tractor ordered at the last minute. This often happens
late in the day, so typically four of the ve ready-mix
drivers you worked with all day have gone home. The
same person who brought the next-to-last load will have
to go and get the balance load. This gives you time to
get ready for cleanout and to stow pipeline, clamps, and
accessories, but if the concrete in your machine will be
old by the time the ready-mix driver returns (This is the
most dangerous time for concrete setting in the ma-
chine), be aware of it, and take any steps necessary to
keep the concrete alive. Clean out, if you must, but if the
balance load is very small, relling the hopper, material
cylinders and pipeline may use up the entire balance
load without ever delivering concrete to the form. In that
case, another balance load would need to be ordered,
and no one is going to be happy about that.
The balance load is usually fresh concrete. That means
that if you pump at least 1/2 yard, your machine will be
lled with fresh concrete for cleanout, which is to your
advantage. The worst thing that can happen is that, on
a hot day, the balance load is only one wheelbarrow
full. You will not be able to get fresh concrete all the way
through the pipe when you pump the balance load, so
the concrete that is in the end of the pipe for cleaning
is as old as the next-to-last load. Be careful! With old
concrete, it is imperative that the pipe be cleaned im-
mediately upon nishing the pour.
• Check your water supply! You will need water for
cleanout.
• If you will be cleaning the pipeline by forcing a
sponge ball through the line with air or water, wet
the ball rst. You can start soaking your sponge
ball in your 5-gallon bucket when 1/2 hour of
pumping remains, or you can start soaking the
ball in the morning; if you let the ball soak all day,
however, it will not last as long.
Hose whip hazard! Never use com-
pressed air to clean out rubber hose.
The result could be a violent whip
of the hose as the air is released. If
water must be conserved, dump the
hoses manually and rinse them with
the water nozzle.
Clean the Hopper
Do not do the following procedure while the pump is
engaged in either Forward or Reverse. The pump must
be in OFF or Neutral position.
Amputation hazard. Stop pump be-
fore cleaning the Rock Valve and
hopper.
Using your hammer, tap on the T-handle that opens the
cleanout door on the bottom of the hopper (Figure 15).
When the door opens, the concrete at the bottom of the
hopper should fall out.
If the concrete does not fall out, aim your hammer up-
ward and pound any material that is lodged in the clea-
nout door. A couple of taps will probably free the materi-
al, but if you need to, keep tapping until it all material is
free. You can minimize or eliminate this procedure
by putting sand or dirt in the bottom of the Rock
Valve housing before you begin pumping.
Figure 22
Opening the Hopper Cleanout Door
For the following procedure, be sure of your footing and
keep the hopper grate in place. Spray water into the
hopper from above (Figure 22).
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