Manitowoc 2250 Service Maintenance Manual

Reference Only
INTRODUCTION 2250 SERVICE/MAINTENANCE MANUAL
1-82
Published 07-19-16, Control # 249-01
Jack Cylinder(s) Retract
When the selected left, right, center, or all switch is held in
the DOWN (retract) position, an input signal is sent to the
PC. A 12 V output signal from the PC enables the jack
cylinder retract solenoid HS-45, HS-47, and/or HS-49.
Internal pilot supply pressure of 14 bar (200 psi) enables the
spool to shift the selected jack cylinder solenoid valve(s).
Internal sequence valve and shuttle valve for each spool
valve controls each system pressure when more than one
valve is operated at a time. The crane’s PC sends an output
signal to shift the crane’s auxiliary system disable-relief valve
HS-12 to block the valve’s bypass. Accessory system
pressure increases to operate the accessory items.
Accessory system fluid enters the MAX-ER’s accessory
valve and flows to the free-flow check valve section of the
counterbalance valve. Fluid pressure on the rod end of the
selected jack cylinder retracts the jack cylinder to lower the
counterweight trailer.
Fluid from the piston end of the jack cylinder is blocked by
the free-flow check valve section of the counterbalance valve
and flow-restraining section of the relief valve preset for a
relief setting of 138 bar (2,000 psi). Piston-end cylinder
pressure opens the restraining section of the counterbalance
valve, allowing fluid to exit the valve. Return hydraulic fluid
then passes through the MAX-ER’s accessory valve before
returning to the crane’s hydraulic tank through the return line.
When the jack cylinder is retracted the desired distance,
release the selected jack switch to the OFF position to lock
the jack cylinder(s) in position. Trapped hydraulic pressure at
the piston end of the jack cylinder counterbalance valve
supports the weight and gravity force of the counterweight
trailer.
RM-07
54MB
54MA
8K
54MRB
54MRA
54MCB
54MCA
54MLB
54MLA
Power
HS
44
HS
45
HS
48
HS
49
HS
46
HS
47
HS
41
HS
40
CB
8K
89J4
89K4
0
15 Amp
5A
Left Jack Extend
Left Jack Retract
Center Jack Retract
Center Jack Extend
Right Jack Extend
Right Jack Retract
All Jack Retract
All Jack Extend
Counterweight Strap
Cylinder Retract
MAX-ER 2000 Remote
Counterweight Strap
Cylinder Extend
HS
12
FIGURE 1-51
89H4
MAX-ER 2000
Programmable
Controller
Auxiliary System
Disable-Relief Valve
Crane
Programmable
Controller
88S

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English