FLUID POWER SYMBOLS

RENR9489
BASIC COMPONENT SYMBOLS
January, 2006
MAIN AUX.
PUMP: VARIABLE and
PUMP or MOTOR FLUID CONDITIONER SPRING CONTROL VALVES RESTRICTION LINE RESTRICTION 2-SECTION PUMP PRESSURE COMPENSATED
(FIXED)

VARIABILITY SPRING LINE RESTRICTION PRESSURE HYDRAULIC PNEUMATIC LINE RESTRICTION ATTACHMENT
(ADJUSTABLE) (VARIABLE) COMPENSATION ENERGY TRIANGLES VARIABLE and PRESSURE
COMPENSATED

VALVES
VALVE ENVELOPES VALVE PORTS

ONE POSITION TWO POSITION THREE POSITION TWO-WAY THREE-WAY FOUR-WAY

CONTROL VALVES CHECK VALVES

AB AB

P T P T
BASIC SPRING SHUTTLE PILOT
NORMAL POSITION SHIFTED POSITION INFINITE POSITION
SYMBOL LOADED CONTROLLED

MEASUREMENT ROTATING SHAFTS

PRESSURE TEMPERATURE FLOW UNIDIRECTIONAL BIDIRECTIONAL

FLUID STORAGE RESERVOIRS

330D Excavator VENTED PRESSURIZED RETURN ABOVE FLUID LEVEL RETURN BELOW FLUID LEVEL

Hydraulic System - Attachment COMBINATION CONTROLS

NBD1-UP SOLENOID SOLENOID SOLENOID SOLENOID and SERVO THERMAL DETENT

or MANUAL and PILOT PILOT or MANUAL
B6H1-UP
MANUAL CONTROL SYMBOLS
MWP1-UP
EDX1-UP
MEY1-UP PUSH-PULL LEVER MANUAL SHUTOFF GENERAL MANUAL PUSH BUTTON PEDAL SPRING

PILOT CONTROL SYMBOLS

RELEASED PRESSURE REMOTE SUPPLY PRESSURE

EXTERNAL RETURN INTERNAL RETURN SIMPLIFIED COMPLETE INTERNAL

SUPPLY PRESSURE

ACCUMULATORS CROSSING AND JOINING LINES HYDRAULIC AND PNEUMATIC CYLINDERS

SPRING LOADED GAS CHARGED LINES CROSSING LINES JOINING SINGLE ACTING DOUBLE ACTING

HYDRAULIC PUMPS HYDRAULIC MOTORS INTERNAL PASSAGEWAYS

FIXED VARIABLE DISPLACEMENT FIXED VARIABLE DISPLACEMENT THREE TWO

INFINITE
DISPLACEMENT NON-COMPENSATED DISPLACEMENT NON-COMPENSATED POSITIONING POSITION POSITION

UNIDIRECTIONAL UNIDIRECTIONAL

FLOW IN ONE PARALLEL CROSS FLOW ALLOWED IN

BIDIRECTIONAL BIDIRECTIONAL DIRECTION FLOW FLOW EITHER DIRECTION

System 3 : Two Pump / One Way Flow

© 2005 Caterpillar Printed in U.S.A.
All Rights Reserved

Electrical Symbols Table

Hydraulic Symbols (Electrical)

G M
Transducer Transducer Generator Electric Motor
(Fluid) (Gas / Air)

Pressure Switch Pressure Switch Temperature Switch Electrical Wire

(Adjustable)

RENR9489
Electrical Symbols (Electrical)

16 Page, B/W
T
Pressure Temperature Level Flow
Symbol Symbol Symbol Symbol

Wire Number Identification Codes

Electrical Schematic Example Hydraulic Schematic Example

Current Standard Current Standard

Harness identification code
This example indicates
wire 135 in harness "AG". Wire
Circuit Number Wire Color
Identification

325-AG135 PK-14
325-PK
Circuit Identification Wire Color Wire Gauge
Number

Previous Standard
Wire Color
Wire

325-PK-14
B A
Circuit Number Wire Gauge
Identification (EXAMPLE VALVE)
 Hydraulic Schematic
255-5857
SWING MOTOR TRAVEL MOTOR (LEFT) TRAVEL MOTOR (RIGHT) This Attachment Schematic is intended to
MEA be used in conjunction with the Standard
S PART NO. NAM Hydraulic Schematic in this Service Manual.
ITEM QTY
X X MISC REF
BUCKET BOOM BOOM - - 171-0188 VALVE GP
CYLINDER CYLINDER CYLINDER MAIN CONNECTOR LINE
PG - - 259-7378 VALVE GP
- - 259-7430 VALVE GP PILOT LINE
DR - - 177-2653 VALVE GP DRAIN LINE
T1 T1 - - 259-7414 SCHEMATIC

MU

HIGH PRESS. LINE 2

1
AR3 BR3 AR4 BR4 aR2 Pa1
SINGLE SINGLE B2 B1
A2 A1
STICK
CYLINDER B1 DR A1

P
4 5 6 1
7
A1
AL3 BL3
A2

B B

3
A A
B1
B A

TP BL2 AL2 P
TT B2
TRAVEL(L) TRAVEL(R)
T
BL1 AL1 BR1 AR1

-µ -µ -µ -µ

BACK FWD FWD BACK

aL2
T1 T5 T2 T4 T6 T3 BR1
aR4 AR4
AL1 aL1 AR1 aR3
aL1 bL1 bR1 aR1 AL1 aR2
AL3

3 2
BL3 BL1 BL1 PST aR1 BR3 AR3 BR4
AL4 SP3 SPi aL3 Di4 Pi4 BR2 AR2 BP3 BDr BPi BR5 AR5 aR5 R3
T Pi1
aL4 (UP) SDr (IN) (L) (REV) (REV) (CLOSE) (DOWN) BP2

FA1 FB1
Pa1

7
6
4 5

STICK(1) SWING TRAVEL(L) BUCKET BOOM(1) STICK(2)

BOOM(2) TRAVEL(R) ATCH
F2 (OUT) (R) (FWD) (FWD) (OPEN) (UP) (OUT)
HL Pb1 Di2 Pi2 Pi3 Di3 Pi5 bR2 Di1 HR
DST bR5
bL1 PL PR bR1 bR3 bR4
bL4 bL3 bL2

Pi1
RENR9489

RR
FR
P2 Pi1 P-IN PSA2 DR1 PSA1 U
B1 A1 B2 A2
16 Page, B/W

PR
T-OUT2 DR2 H
T

B 1E2722D DRAWING
(TRAVEL)

(SWING)

1E0013Y CONFIDENTIALITY
D0
NO.1

NO.2

T PS1 a1
C
(LOCK)

JLP JLT JRP JRT

NO.3

B A1
STICK SWING BUCKET BOOM P1 P2
a4
G
A P1 Components List
-µ -µ -µ -µ
Part No. Description
-µ -µ -µ -µ

D E F PSV 1 Line Relief Valve - One Way Flow (Work Tool)

OUT IN R L OPEN CLOSE DOWN UP A 2 Solenoid Valve (Work Tool)
JL1 JL3 JL2 JL4 JR4 JR2 JR3 JR1 3 Proportional Pressure Reducing Valve - Negative Flow
DR3 DR4 Pi2 T-OUT1 DR6
DR5 a3 Line Relief Valve
L
L1 S 4
5 Line Relief Valve
T P a5 6 Auxiliary Control Valve
DR1 DR L3 L2
A2 7 Attachment Control Valve
A1 A2 A3 A4 A5 A6 A7 A8 A4 B Dr1 Di PS2 a2

OUT IN
PL
B A
T
B1 B2 B3 B4 B5 B6 B7 B8
PG PC

Pi2
aR3 aR3 bR3 bR4 bL3 bL2 bL4 aL2