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MAYCO LS400/LS500 PUMP — OPERATION AND PARTS MANUAL — REV. #6 (09/19/11) — PAGE 35
DO NOT open any of the delivery system joint clamps.
“REVERSE” PUMPING PROCEDURE
A. Switch the pump into REVERSE. With pump speed
at a medium-slow (approx. 12 strokes per min.) try
to pull the “pack” back into the hopper with 5 or 6
reverse strokes.
B. Remix the concrete in the hopper.
C. Switch the pump into
FORWARD. If it is still plugged,
repeat “Reversing” procedure three times.
If concrete still does not move, proceed to the Shuttle Tube
Inspection Procedure.
The shuttle tube is plugged if volume at the discharge end of
the hose stops and the hydraulic oil pressure gauge reads
4400 PSI or more.
To clear a plug in the shuttle tube, great care must be taken
as a dangerous condition will exist from pressure build-up
inside the shuttle tube. (With the shuttle valve, the concrete
can be pumped in reverse.) Use the following procedures to
clear the shuttle tubes.
WARNING - SHUTTLE TUBES
CLEARING SHUTTLE TUBE BLOCKAGE
Make sure the accumulator pressure gauge reads
ZERO psi. prior to performing any maintenance or
inspection. You must follow lock out-tag out
procedures.
WARNING - ACCUMULATOR PRESSURE
SHUTTLE TUBE INSPECTION PROCEDURE
A. Stop the pump. Switch off the engine.
B The senior or most experienced operator must warn
all others to stand at least 20 feet away from the
machine and turn their heads to face away from the
pump.
C. The operator will position himself beside the reducing
elbow at the pump outlet. Wearing
safety glasses
,
slip the end of a pry bar (24" length of reinforcing
steel rod) under the latch of the hose clamp and flip
it up.
D. Carefully knock the end of the hose away from the
reducer.
E. Chip the concrete out of the reducer with the pry
bar.
F. Remove the reducer. From the discharge end, chip
the concrete out of the shuttle tube with the pry-bar.
If concrete cannot be loosened from the outlet of
the shuttle tube, remove the clean-out plug on the
bottom of the hopper to discharge the concrete.
G. Chip the blockage out with the pry-bar.
H. Flush the shuttle tube with water.
I. Before resuming operation of the pump, perform the
“Reverse” Pumping Procedure to relieve pressure
on the shuttle tubes.
LS400/LS500 PUMP — PUMPING INFORMATION