R978919344 - BuyRexroth

Manufacturer: Bosch Rexroth

Material #: R978919344

Model : 4WRTE25W6-350L-4X/6EG24K31/A5M

$12,112.00 USD

More are expected on December 8, 2025

Add to Cart

Note: Sales tax, shipping, and applicable tariffs will be calculated at checkout.

Qty	Price	Savings
5-24	$11,809.20 USD	$302.80 USD
25+	$11,506.40 USD	$605.60 USD

Status: This product is temporarily out of stock.

Qty: Delivered as early as December 8, 2025 when ordered in

This product is eligible for factory repair.

Repairs from $1,200.00

Reliable - proven and robust design Safe
- Automatic pressure compensation in the control chambers of the main stage by the pilot controlvalve
- Control spool of the main stage in the springcentered central position and/or in the offset position
- Optionally with spool position monitoring Flexible - suitable for position, velocity and pressure control Precise - high response sensitivity and little hysteresis

Valves of type 4WRTE are pilot-operated directional control valves with electrical position feedback, integrated electronics (OBE) and optional spool position monitoring.

Set-up

The valve basically consists of 3 main assemblies:

Housing (1) with main stage control spool (2) and optional spool position monitoring (13) Integrated electronics (optionally with electronics protection membrane (14)) with inductive position transducer (3) of the main stage Pilot control valve (4) with control spool/socket unit (5), inductive position transducer (6) and pressure feed back for central position of the main stage control spool (2)

Function

With de-energized proportional solenoids (7; 8) central position of the main stage control spool (2) due to centering spring (9) and pressure feed back Control of the main stage control spool (2) via the pilot control valve (4) → the main stage control spool (2) is positioned in a regulated manner Controlling the control spool of the pilot control valve (4) by changing the solenoid force of the proportional solenoids (7; 8) Connection of the command and actual values in the integrated electronics Pilot oil supply to the pilot control valve internally via port P or externally via port X Pilot oil return internally via port T or externally via Y to the tank With a command value of 0 V, the electronics control the main stage control spool (2) in central position

Spool position monitoring

The spool positions of the main stage control spool (2) are detected by the inductive position switch (13) and displayed via two switching outputs with a preset logic. If the fixedly set switching points are exceeded, the deviation from the zero position is monitored within the control spool overlap (see "Accessories").

The switching signals can be used in a superior control for monitoring functions. The electrical connection is implemented separately via a 4-pole connector M12x1 with two pins for signal output and two pins for voltage supply.

Area of application

The valve can be used in safety-related two-channel applications (category 3, PL d and category 4, PL e according to EN 13849-1) as switch-off element for one channel. The valve meets the requirements of a secure start inhibitor according to EN 60204, stop category 0.

If safety requirements are needed, the supply voltage of the valve must be safely disconnected based on the

required safety level (category PL).

Depending on the application and the requirements of work equipment-specific standards according to EN 13849-1, the user must provide appropriate monitoring/plausibility checks which comply with the required

diagnostic coverage DCavg using a superior control.

Electronics protection membrane "-967"

To prevent condensate formation in the housing of the integrated electronics (OBE), an electronics protection

membrane (14) can be used.

Recommended for use outside industry-standard conditions with high ambient air humidity and significant cyclic temperature changes (e. g. outdoors).

Failure of supply voltage

Integrated electronics de-energize the solenoid in case of supply voltage failure or cable break Automatic pressure control on the same level in the control chambers (10 and 11) by the pilot control valve In case of pressure supply failure, centering of the main stage control spool by centering spring (9) Central position of the main stage control spool (2)

Notices:

Failure of the supply voltage will lead to an abrupt standstill of the control axis. The acceleration forces occurring in this connection may cause machine damage.
With control spool symbols E, E1-, W6- and W8-, the centering spring (9) sets the main stage control spool (2) in central position, control spools V- and V1 are switched to the preferred direction P to B and A to T in a tolerance range of 1% to a maximum of 11% of the control spool stroke. The PG fitting (12) must not be opened. Mechanical adjustment of the adjustment nut located below is prohibited and damages the valve. The zero point has been adjusted at the factory. Changes in the zero point may result in damage to the system and may only be implemented by instructed specialists. If the pilot control valve or the electronics are exchanged, the zero point has to be adjusted once again by instructed specialists.

Pilot oil supply

(schematic illustration)

Size 10

Size 16

Size 25

Size 27

Size 32

Size 35

1	Plug screw M6 according to DIN 906, wrench size 3 – pilot oil return
2	Plug screw M6 according to DIN 906, wrench size 3 – pilot oil supply
3	Plug screw M12 x 1.5 according DIN 906, wrench size 6 – pilot oil supply
4	Plug screw M10 x 1 according to DIN 906, wrench size 5 – pilot oil return
5	Plug screw M10 x 1 according DIN 906, wrench size 5 – pilot oil supply
6	Main stage housing cover (opposite the OBE)

Pilot oil supply external: 2, 3, 5 closed

Pilot oil supply internal: 2, 3, 5 open

Pilot oil return external: 1, 4 closed

Pilot oil return internal: 1, 4 open

"No code" version

External pilot oil supply

External pilot oil return

In this version, the pilot oil is supplied from a separate control circuit (external).

The pilot oil return is not directed into channel T of the main valve, but is separately directed to the tank via port Y (external).

Version "E"

Internal pilot oil supply

External pilot oil return

With this version, the pilot oil is supplied from channel P of the main valve (internally).

The pilot oil return is not directed into channel T of the main valve, but is separately directed to the tank via port Y (external).

In the subplate, port X is to be closed.

Version "ET"

Internal pilot oil supply

Internal pilot oil return

With this version, the pilot oil is supplied from channel P of the main valve (internally).

The pilot oil is directly returned to channel T of the main valve (internally).

In the subplate, ports X and Y are to be closed.

Version "T"

External pilot oil supply

Internal pilot oil return

In this version, the pilot oil is supplied from a separate control circuit (external).

The pilot oil is directly returned to channel T of the main valve (internally).

In the subplate, port Y is to be closed.

01	02	03	04	05	06	07	08		09		10	11	12	13		14	15	16	17
4	WRT	E						‒	4X	/	6E	G24		K31	/				*

01	4 main ports	4
02	High-response directional valve, pilot operated	WRT
03	With integrated electronics (OBE)	E
04	Without spool position monitoring	no code
04	With spool position monitoring (NG16 … NG35 only)	M
05	Size 10	10
	Size 16	16
	Size 25	25
	Size 27	27
	Size 32	32
	Size 35	35
06	Symbols; for the possible version, see "Symbols/Circuit diagrams"
Rated flow (Δp = 5 bar/control edge)
07	Size 10
	25l/min 1)	25
	50l/min 2)	50
	90 l/min	100
	Size 16
	150l/min 3)	150
	220l/min	220
	Size 25
	220l/min	220
	350 l/min	350
	Size 27
	500 l/min	500
	Size 32
	400 l/min	400
	600 l/min	600
	Size 35
	1000 l/min	1000
Flow characteristic
08	Linear	L
08	Linear with fine control range	P
09	Component series 40 … 49 (40 … 49: unchanged installation and mounting dimensions)	4X
Pilot control valve
10	Proportional solenoid with detachable coil (NG6)	6E
Power supply
11	Direct voltage 24 V	G24
Pilot oil flow
12	External pilot oil supply, external pilot oil return	no code
	Internal pilot oil supply, external pilot oil return	E
	Pilot oil supply internal, pilot oil return internal	ET
	External pilot oil supply, internal pilot oil return	T
Electrical connection
13	Without mating connector, with connector according to DIN EN 175201-804	K31 4)
Electrical interface
14	Command value/actual value ±10 V	A1
	Command value/actual value 4 … 20 mA	F1
	Command value/actual value ±10 V, enable signal (pin C)	A5 5)
Seal material
15	NBR seals	M
15	FKM seals	V
16	Without electronics protection membrane	no code
16	With electronics protection membrane	-967
17	Further details in the plain text	*

1)	Symbol E, W6-, W8- and V only with flow characteristic "L"
2)	Symbol E1-, W8- and V1 only with flow characteristic "L"
3)	Symbol V1 only with flow characteristic "L"
4)	Mating connectors, separate order, see "Accessories"
5)	When replacing the component series 3X by 4X, the electronics interface is to be defined with A5 (enable signal at pin C).

For applications outside these parameters, please consult us!

general

Type		4WRTE
Size		10	16	25	27	32	35
Component series		4X
Installation position		any, preferably horizontal
Earth	kg	8.7	11.2	16.8	17	31.5	34
Ambient temperature range	°C	-20 … +50
Sine test according to DIN EN 60068-2-6		10 ... 2000 Hz / maximum 10 g / 10 cycles / 3 axes
Noise test according to DIN EN 60068-2-64		20 ... 2000 Hz / 10 gRMS / 30 g peak / 30 min / 3 axes
Transport shock according to DIN EN 60068-2-27		15 g / 11 ms / 3 shocks / 3 axes
MTTFD values according to EN ISO 13849 1)	Years	150
Damp heat according to DIN EN 60068-2-30		Variant 2: +25 °C … +55 °C, 90 % … 97 % relative humidity, 2 cycles á 24 hours

1)	With symbol E, E1, W6 and W8; in longitudinal control spool direction, there is sufficient positive overlap without shock/vibration load; observe the installation orientation with regard to the main direction of acceleration.

hydraulic

Type				4WRTE
Size				10	16	25	27	32	35
Maximum operating pressure			bar	350			270	350
Maximum operating pressure	Port P		bar	350			270	350
	Anschluss A		bar	350			270	350
	Port B		bar	350			270	350
Maximum operating pressure	Pilot control valve	Pilot oil supply 1)	bar	25 … 315
Maximum return flow pressure	Port T	Internal pilot oil supply		static < 10 bar
	Port T	External pilot oil supply	bar	315	250		210	250
	Port Y			static < 10 bar
Nominal flow 2)			l/min	25 50 100	125 150 200 220	220 350	500	400 600	1000
Maximum flow			l/min	170	460	870	1000	1600	3000
Pilot flow 3)			l/min	7	14	20		27	29
Pilot volume 0 … 100%			cm³	1.1	2.9	6.8		17.7	33.9
Hydraulic fluid temperature range			°C	-20 … +80
	preferably		°C	+40 … +80
Viscosity range			mm²/s	20 … 380
	preferably		mm²/s	30 … 45
Maximum admissible degree of contamination of the hydraulic fluid, cleanliness class according to ISO 4406 (c) 4)				Class 18/16/13 according to ISO 4406 (c)
Hysteresis			%	≤ 0.1
Response sensitivity			%	≤ 0.05
Temperature drift			%/10° C	< 0.3

1)	For perfect system behavior, we recommend an external pilot oil supply for pressures above 210 bar.
2)	qV nom ±10% with Δp = 5 bar/control edge; flow for deviating Δp see formula.
3)	At port X or Y with stepped input signal from 0 to 100% (315 bar)
4)	The cleanliness classes specified for the components must be adhered to in hydraulic systems. Effective filtration prevents faults and simultaneously increases the life cycle of the components. For the selection of the filters, see www.boschrexroth.com/filter.

Hydraulic fluid		Classification	Suitable sealing materials	Standards	Data sheet
Mineral oils		HL, HLP, HLPD, HVLP, HVLPD	NBR, FKM	DIN 51524	90220
Bio-degradable	Insoluble in water	HETG	NBR, FKM	ISO 15380	90221
	Insoluble in water	HEES	FKM	ISO 15380
	Soluble in water	HEPG	FKM	ISO 15380
Flame-resistant	Water-free	HFDU, HFDR	FKM	ISO 12922	90222
Flame-resistant	Containing water	HFC (Fuchs Hydrotherm 46M, Petrofer Ultra Safe 620)	NBR	ISO 12922	90223
Important information on hydraulic fluids: For further information and data on the use of other hydraulic fluids, please refer to the data sheets above or contact us. There may be limitations regarding the technical valve data (temperature, pressure range, life cycle, maintenance intervals, etc.). The ignition temperature of the hydraulic fluid used must be 40 K higher than the maximum solenoid surface temperature. Flame-resistant – containing water: Maximum operating pressure 210 bar Maximum pressure differential per control edge 175 bar Pressure pre-loading at the tank port >20% of the pressure differential, otherwise increased cavitation erosion Life cycle as compared to operation with mineral oil HL, HLP 50 … 100% Maximum hydraulic fluid temperature 50 °C

electrical

Type			4WRTE
Voltage type			Direct voltage
Power supply	Nominal voltage	VDC	24
	Lower limit value	VDC	18
	Upper limit value	VDC	35
Maximum admissible residual ripple 1)		Vpp	2.5
Maximum current consumption	of the amplifier	A	1.6
Maximum current consumption	of the amplifier (impulse current)	A	2.7
Maximum coil temperature 2)		°C	150
Duty cycle		%	100
Maximum power consumption			72 VA (average = 24 VA)
Required fuse protection		AT	4 (time-lag)
Protection class according to DIN EN 60529			IP65 (If a suitable and a correctly mounted mating connector are used.)
Zero point calibration 3)		%	≤ 1
Voltage input "A1" (differential input)	Measurement range	VDC	-10 ... +10
Voltage input "A1" (differential input)	Input resistance	Ω	100
Current input "F1"	Input current	mA	4 ... 20
Current input "F1"	Input resistance	Ω	100
Enable input "A5"	Low level	VDC	0 ... 2
Enable input "A5"	High level	VDC	> 11

1)	Observe the absolute limit values of the supply voltage.
2)	Due to the surface temperatures of the solenoid coils, the standards ISO 13732-1 and ISO 4413 (contact protection) must be observed.
3)	Related to the pressure-signal characteristic curve (symbol V), ex works

Inductive position switch: Electrical connection

The electrical connection is realized via a 4-pole mating connector (separate order, see "Accessories") with connection thread M12 x 1.

Inductive position switch: Switching logics

Position switch on side A, monitored spool position "0"

➀	Central position (mechanical control spool overlap)
➁	Valve opening P→B
➂	Valve opening P→A

(measured with HLP46, ϑOil = 40 ±5 °C)

Pressure amplification measured with p = 100 bar)

Maximum zero flow of the main stage (symbol V) with pilot control valve

Maximum internal leakage of the main stage (symbol W) with pilot control valve

Flow command value function (Δp = 5 bar/control edge)

Symbol E, W and V, Version "L"

Flow command value function (Δp = 5 bar/control edge)

Symbol E, W and V, Version „P“

Size 10

Transition function with stepped electric input signals

Frequency response

Flow/load function with maximum valve opening (tolerance ±10 %)

Size 16

Transition function with stepped electric input signals

Frequency response

Flow/load function with maximum valve opening (tolerance ±10 %)

Size 25 and 27

Transition function with stepped electric input signals

Frequency response

Flow/load function with maximum valve opening (tolerance ±10 %)

Size 32

Transition function with stepped electric input signals

Frequency response

Flow/load function with maximum valve opening (tolerance ±10 %)

Size 35

Transition function with stepped electric input signals

Frequency response

Flow/load function with maximum valve opening (tolerance ±10 %)

Symbols

Symbol E1-, V1- and W8-:
P → A: qv max P → B: qv/2	B → T: qv/2 A → T: qv max

Version	simple	Detailed
no code
"E"
"ET"
"T"

1	Pilot control valve
2	Main valve
3	Integrated electronics (OBE)
4	Design with spool position monitoring "M"

Notice:

Representation according to DIN ISO 1219-1. Hydraulic interim positions are shown by dashes.

Electrical connections and assignment

Connector pin assignment

Pin	Signal	Assignment interface "A1"	Assignment interface "F1"	Signal with interface A5
A	Power supply	24 VDC
B	Power supply	0 V
C	Reference potential (actual value)/enable signal	Reference potential actual value (pin F)		Enable signal >11 VDC
D	Differential amplifier input (command value)	± 10 V	4 ... 20 mA	± 10 V
E	Differential amplifier input (command value)	0 V reference potential (pin D)		0 V reference potential (pin D and F)
F	Measuring output (actual value)	± 10 V	4 ... 20 mA	± 10 V
PE		Functional ground (directly connected to valve housing)

	Command value	Reference potential at E and positive command value at D result in flow from P → A and B → T.
		Reference potential at E and negative command value at D result in flow from P → B and A → T.
	Connection cable (recommendation)	Up to 25 m cable length type LiYCY 7 x 0,75 mm2
		Up to 50 m cable length type LiYCY 7 x 1,0 mm2
		Connect shield on PE only on the supply side

Notices:

Electrical signals provided via valve electronics (e.g. actual value) must not be used to switch off safety-relevant machine functions. Mating connectors, separate order, see "Accessories".

Block diagram: Integrated electronics (OBE)

Size 10

Dimensions in mm


Required surface quality of the valve contact surface

1	Pilot control valve
2	Electrical connection
3	Wiring and mating connector
4	Inductive position transducer (pilot control valve)
5	Mating connectors, separate order, see "Accessories"
6	Name plate
7	Main valve
8	Integrated electronics (OBE) and inductive position transducer (main valve)
9	Identical seal rings for ports X and Y
10	Identical seal rings for ports A, B, P and T (T1)
11	Space required for connection cable and to remove the mating connector
12	Machined valve contact surface; Porting pattern according to ISO 4401-05-05-0-05 (ports X, Y as required)

Valve mounting screws (separate order):

4 hexagon socket head cap screws ISO 4762 - M6 x 45 - 10.9-CM-Fe-ZnNi-5-Cn-T0-H-B

Tightening torque MA = 13,5 Nm ±10 %, material no. R913043777

4 hexagon socket head cap screws ISO 4762 - M6 x 45 - 10.9

Tightening torque MA = 15,5 Nm ±10 %, ot included in the Rexroth delivery range

Notice:

The tightening torque of the hexagon socket head cap screws refers to maximum operating pressure!

Size 16

Dimensions in mm


Required surface quality of the valve contact surface

1	Pilot control valve
2	Electrical connection
3	Wiring and mating connector
4	Inductive position transducer (pilot control valve)
5	Mating connectors, separate order, see "Accessories"
6	Name plate
7	Main valve
8	Integrated electronics (OBE) and inductive position transducer (main valve)
9	Identical seal rings for ports X and Y
10	Identical seal rings for ports A, B, P and T (T1)
11	Space required for connection cable and to remove the mating connector
12	Machined valve contact surface, porting pattern according to ISO 4401-07-07-0-05 (ports X, Y as required). Deviating from the standard: ports A, B, P, T – Ø20 mm
13	Locking pin

Valve mounting screws (separate order):

2 hexagon socket head cap screws ISO 4762 - M6 x 60 - 10.9-CM-Fe-ZnNi-5-Cn-T0-H-B
Tightening torque MA = 12.2 Nm ±10 %, material no. R913043410 4 hexagon socket head cap screws ISO 4762 - M10 x 60 - 10.9-flZn/nc/480h/C
Tightening torque MA = 58 Nm ±20 %, material no. R913014770

2 hexagon socket head cap screws ISO 4762 - M6 x 60 - 10.9
Tightening torque MA = 15,5 Nm ±10 %, not included in the Rexroth delivery range 4 Hexagon socket head cap screws ISO 4762 - M10 x 60 - 10.9
Tightening torque MA = 75 Nm ±20 %, not included in the Rexroth delivery range

Notice:

The tightening torque of the hexagon socket head cap screws refers to maximum operating pressure.

Size 25

Dimensions in mm


Required surface quality of the valve contact surface

1	Pilot control valve
2	Electrical connection
3	Wiring and mating connector
4	Inductive position transducer (pilot control valve)
5	Mating connectors, separate order, see "Accessories"
6	Name plate
7	Main valve
8	Integrated electronics (OBE) and inductive position transducer (main valve)
9	Identical seal rings for ports X and Y
10	Identical seal rings for ports A, B, P, and T
11	Space required for connection cable and to remove the mating connector
12	Machined valve contact surface; Porting pattern according to ISO 4401-08-08-0-05 (ports X, Y as required)
13	Locking pin

Valve mounting screws (separate order):

6 hexagon socket head cap screws ISO 4762 - M12 x 60 - 10.9-flZn/nc/480h/C

Tightening torque MA = 100 Nm ±20 %, Material-Nr. R913015613

6 hexagon socket head cap screws ISO 4762 - M12 x 60 - 10.9

Tightening torque MA = 130 Nm ±20 %, not included in the Rexroth delivery range

Notice:

The tightening torque of the hexagon socket head cap screws refers to maximum operating pressure.

Size 27

Dimensions in mm


Required surface quality of the valve contact surface

1	Pilot control valve
2	Electrical connection
3	Wiring and mating connector
4	Inductive position transducer (pilot control valve)
5	Mating connectors, separate order, see "Accessories"
6	Name plate
7	Main valve
8	Integrated electronics (OBE) and inductive position transducer (main valve)
9	Identical seal rings for ports X and Y
10	Identical seal rings for ports A, B, P, and T
11	Space required for connection cable and to remove the mating connector
12	Machined valve contact surface; Porting pattern according to ISO 4401-08-08-0-05 (Ports X, Y as required) Deviating from the standard: Ports A, B, T and P Ø32 mm
13	Locking pin

Valve mounting screws (separate order):

6 hexagon socket head cap screws ISO 4762 - M12 x 60 - 10.9-flZn/nc/480h/C

Tightening torque MA = 100 Nm ±20 %, Material-Nr. R913015613

6 hexagon socket head cap screws ISO 4762 - M12 x 60 - 10.9

Tightening torque MA = 130 Nm ±20 %, not included in the Rexroth delivery range

Notice:

The tightening torque of the hexagon socket head cap screws refers to maximum operating pressure.

Size 32

Dimensions in mm


Required surface quality of the valve contact surface

1	Pilot control valve
2	Electrical connection
3	Wiring and mating connector
4	Inductive position transducer (pilot control valve)
5	Mating connectors, separate order, see "Accessories"
6	Name plate
7	Main valve
8	Integrated electronics (OBE) and inductive position transducer (main valve)
9	Identical seal rings for ports X and Y
10	Identical seal rings for ports A, B, P, and T
11	Space required to remove the mating connector
12	Machined valve contact surface; Porting pattern according to ISO 4401-10-09-0-05 (Ports X, Y as required). Deviating from the standard: – Ports P, A, B and T – Ø38 mm – Dimension G1 according to DIN 24340 Form A
13	Locking pin

Valve mounting screws (separate order):

6 hexagon socket head cap screws ISO 4762 - M20 x 80 - 10.9-flZn/nc/480h/C

Tightening torque MA = 340 Nm ±20 %, material no. R913008472

6 hexagon socket head cap screws ISO 4762 - M20 x 80 - 10.9

Tightening torque MA = 430 Nm ±20 %, not included in the Rexroth delivery range

Notice:

The tightening torque of the hexagon socket head cap screws refers to maximum operating pressure.

Size 35

Dimensions in mm


Required surface quality of the valve contact surface

1	Pilot control valve
2	Electrical connection
3	Wiring and mating connector
4	Inductive position transducer (pilot control valve)
5	Mating connectors, separate order, see "Accessories"
6	Name plate
7	Main valve
8	Integrated electronics (OBE) and inductive position transducer (main valve)
9	Identical seal rings for ports X and Y
10	Identical seal rings for ports A, B, P, and T
11	Space required for connection cable and to remove the mating connector
12	Machined valve contact surface; Porting pattern according to ISO 4401-10-09-0-05 (Ports X, Y as required). Deviating from the standard: – Ports P, A, B and T – Ø50 mm – Dimension G1 according to DIN 24340 Form A
13	Locking pin

Valve mounting screws (separate order):

6 hexagon socket head cap screws ISO 4762 - M20 x 100 - 10.9-flZn/nc/480h/C

Tightening torque MA = 465 Nm ±20 %, material no. R913015670

6 hexagon socket head cap screws ISO 4762 - M20 x 100 - 10.9

Tightening torque MA = 610 Nm ±20 %, not included in the Rexroth delivery range

Notice:

The tightening torque of the hexagon socket head cap screws refers to maximum operating pressure.

Spool position monitoring "M" and electronics protection membrane "-967"

Dimensions in mm

14	Electronics protection membrane "-967"
15	Spool position monitoring "M", optional

NG	L1	L2
NG	mm	mm
10	240
16	286	151
25	347	143
27	353	144
32	422	168
35	463	201

Notice:

The dimensions are nominal dimensions which are subject to tolerances.

Project planning, installation and commissioning

When designing safety-related controls, observe the applicable industry-specific standards and regulations. Due to the flexible use of valves in systems, the user has to check and ensure that the product properties comply with all functional and safety requirements of the overall system. Make sure that there are no switching shocks and that the valve control spool does not vibrate. Valves with spool position indicator may only be installed, adjusted, commissioned and maintained by specialists trained in hydraulics and electronics. Improper work at safety-related parts of controls may result in personal injury and damage to property.

The following applies to all work carried out at the valve:

Valves with spool position indicator must not be disassembled. The parts of the valves must not be exchanged. Integrated throttles must not be removed or modified. The spool position indicator may only be adjusted by the valve manufacturer.