MULTIQUIP LS450 - Troubleshooting (Pump); Main Hydraulic Cylinder will not cycle; Hopper Remix Paddles will not rotate; Shuttle Cylinder does not stroke

PAGE 76 — MAYCO LS450 CONCRETE PUMP • OPERATION MANUAL — REV. #2 (02/23/21)
TROUBLESHOOTING (PUMP)
Troubleshooting (Pump)
Symptom Possible Problem Solution
Main Hydraulic Cylinder will
not cycle
Incorrect System Operating Pressure
Check the pump pressure gauge. Verify it is
approx. 4,300–4,400 PSI
Incorrect Engine RPM setting
Verify the engine’s high RPM speed is set to
2,400
Contaminated Main Relief Valve
Check the manifold for a contaminated Relief
Valve
Obstructed Material Cylinders
Check for obstructions (dried material) inside
the cylinders
Hopper Remix Paddles will
not rotate
Incorrect Directional Control
Operating Pressure
Verify the Directional Control operating
pressure is approx. 1,000 PSI
Contaminated Relief Valve
Check the manifold for a contaminated Relief
Valve
Broken Shaft Coupler Key
Check the Hopper Remixer shaft coupler for a
broken key
Loose Shaft Retaining Set Collar
Check the Shaft Retaining Set Collar for
tightness
Shuttle Cylinder does not
stroke
Incorrect Accumulator System
Pressure
Check the system pressure reading. Verify it is
approx. 1,750 PSI
Contaminated Relief Valve
Check the manifold for a contaminated Relief
Valve
Swing Solenoid not energizing
Check for burned out solenoid and 12V signal
voltage
Swing Valve not functioning properly
Manually cycle the pump using the manual
cylinder jogging switch
Shuttle Cylinder slow to
complete stroke
Improper Flow Control setting Fully open Flow Control Vave
Incorrect Engine RPM setting
Verify the engine’s high RPM speed is set to
2,400
Incorrect Main Hydraulic
System Operating Pressure
Check the pump pressure gauge. Verify it is
approx. 4,300–4,400 PSI
Contaminated Swing Relief Cartridge
Check the manifold for contaminated Swing
Relief Cartridge
Low Accumulator System Pressure
Check the accumulator pressure reading. Verify
it is approx. 1,750 PSI
Hopper Discharge Nipple Seal
improperly lubricated
Check the Hopper Discharge Nipple Seal for
seizing and lack of lubricant
Concrete slurry in
lubrication box
Worn or defective urethane cups or
worn material cylinder
Replace
Material cylinder piston
cups squeal
Low on lubrication Check oil level