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Overview
SP 500 / 750-15 / 750-18 / 1000 / 1250 Operation Manual
Manual Bleed-O Valve
The accumulator should dump pressure when the en-
gine is stopped or E-stop button is pressed. If pressure
still exists (check accumulator pressure gauge), relieve
the remaining accumulator pressure using the manual
bleed valve on the accumulator manifold.
Manual Bleed-Off Valve
Accumulator Manifold
Figure 6
Accumulator manual bleed-o valve
Pressure Relief Valves
Pressure relief valves limit maximum pressure in a hy-
draulic circuit by diverting excess oil to the hydraulic
tank when maximum pressures are exceeded. The re-
lief pressures listed on the hydraulic schematics are not
nominal gures. They are the hydraulic relief pressures
that the concrete pump was designed to work with and
that the components were designed to accommodate.
Under no circumstances should you raise hy-
draulic relief pressures. Conversely, lowering the
hydraulic relief pressure settings may cause poor
performance, heat, and related premature com-
ponent failure. In some extreme cases, raising or
lowering hydraulic relief pressures may cause
dangerous operation. Check with the Schwing
America Service Center before changing any hy-
draulic relief pressure settings.
Concrete Pump
Main Relief Valve
Soft Switch
Relief Valve
Figure 7
Example of a pressure relief valves
Safety guards
Safety guards were placed for your protection. Do not
operate the machine unless all the safety guards are
in place. If they become damaged, lost, stolen, or in-
operable for any reason, they must be replaced before
operation continues.
Waterbox Cover
Figure 8
Example Safety Guard - Waterbox Cover
Fuses and circuit breakers
Fuses and circuit breakers protect against circuit over-
load. They do so by melting or opening when the cur-
rent in an electrical circuit becomes higher than it was
designed for. Here are a couple of examples of causes
for circuit overload:
• Short circuits (positive goes to negative without
resistance)
• Component malfunction (a coil that has to move
a sticky valve)
• Mechanical interference (a shovel handle stuck
through the oil cooler fan blade)
To maintain this safety device, simply replace a blown
fuse with the correct size and type fuse, and never by-
pass a fuse. A very good rule of thumb for fuses is this:
If it blows once, replace it. If it blows again, something
is wrong. Find the cause of the problem, and repair it
before activating the circuit again.
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