Single vs Double Solenoid Directional Valves: Selection Guide

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Single Solenoid vs Double Solenoid Directional Valves: How to Select

2026-08-28

When selecting a hydraulic directional valve, one of the first questions is often:

Should I use a single solenoid valve or a double solenoid valve?

Both designs are widely used in industrial and mobile hydraulic systems, but they behave differently when electrical power is applied or removed.

A single solenoid directional valve typically uses one electromagnetic coil and a spring to move the spool between operating positions. A double solenoid directional valve uses two solenoids to control spool movement in opposite directions.

However, the number of solenoids alone does not completely determine the hydraulic function.

The correct choice also depends on:

Number of spool positions
Hydraulic symbol
Neutral condition
Required fail-safe position
Control sequence
Cylinder or motor behavior
Electrical control system

Understanding these differences can help avoid selecting a valve that physically fits the equipment but does not operate correctly.

What Is a Single Solenoid Directional Valve?

A single solenoid directional valve uses one electromagnetic coil to shift the internal spool.

When the coil is energized, magnetic force moves the spool to the commanded position. When electrical power is removed, a mechanical spring commonly returns the spool to its normal position.

A simple operating sequence can be represented as:

Power OFF → Spring Return Position

Power ON → Solenoid-Actuated Position

This makes single solenoid valves useful where the machine requires a clearly defined position when electrical power is removed.

For example, a hydraulic cylinder may need to return, stop or unload according to the selected spool function when the coil is de-energized.

Single solenoid configurations are common in valve series such as 4WE6, 4WE10 and DSG directional valves.

What Is a Double Solenoid Directional Valve?

A double solenoid valve has two electromagnetic coils, normally installed on opposite ends of the valve.

One solenoid moves the spool in one direction, while the other moves it in the opposite direction.

For example:

Solenoid A energized → Spool shifts toward position A

Solenoid B energized → Spool shifts toward position B

Double solenoid directional valves are frequently used when hydraulic cylinders or motors need electrical control in both directions.

Depending on the spool and spring design, a double solenoid valve may be:

Two-position
Three-position
Spring-centered
Detented or memory-type

This is why “double solenoid” should not automatically be understood as one specific hydraulic function.

The hydraulic symbol is more important than the number of coils.

The Main Difference: What Happens When Power Is Removed?

One of the most important differences between single and double solenoid valves is the spool behavior after the electrical signal disappears.

Single Solenoid Valve

A typical single solenoid valve uses a spring return.

When the coil is switched off, the spool automatically returns to its normal position.

This provides a predictable mechanical default condition.

For some machines, this is useful for safety or operational reasons.

Double Solenoid Valve

The behavior depends on the valve design.

A three-position double solenoid valve often uses springs to return the spool to a center position when both coils are de-energized.

A two-position detented double-solenoid valve, however, may remain in the last selected position even after the electrical signal is removed.

Therefore, designers should not assume that all double solenoid valves behave the same way during power loss.

Single Solenoid vs Double Solenoid: Key Differences

Comparison	Single Solenoid	Double Solenoid
Number of coils	1	2
Common control	Energize / spring return	Electrical control in both directions
Wiring	Simpler	More control wiring
Power-off behavior	Usually returns by spring	Depends on spring/detent design
Common positions	Often 2-position	Often 2- or 3-position
Control flexibility	Simpler	More flexible
Typical use	Simple cylinder control	Bidirectional or multi-position control
Cost and wiring	Usually lower	Usually slightly more complex

The table is only a general comparison. The actual valve function should always be confirmed from the hydraulic symbol.

When Should You Choose a Single Solenoid Valve?

A single solenoid valve is often suitable when the system requires a defined return position after power is removed.

Typical applications include:

Simple hydraulic cylinder control
Clamping and releasing systems
Loading and unloading mechanisms
Hydraulic power units
Machine auxiliary movements
Equipment requiring automatic spring return

For example, a cylinder may extend when the coil is energized and return when the electrical signal is removed.

This provides relatively simple electrical control because the PLC or controller only needs to switch one coil.

Single solenoid valves can also reduce wiring complexity where the machine does not require independent electrical commands for both spool directions.

When Is a Double Solenoid Valve Better?

A double solenoid valve is useful when the control system needs more direct electrical control over the spool.

Typical applications include:

Double-acting hydraulic cylinders
Hydraulic motor forward/reverse control
CNC and industrial machinery
Automated production equipment
Material handling systems
Hydraulic presses
Equipment requiring three spool positions

For a double-acting cylinder, one solenoid may control extension while the second controls retraction.

If a three-position spool is used, releasing both solenoids can return the valve to the center position.

The exact center condition then determines what happens to P, T, A and B.

Neutral Position Is More Important Than Coil Quantity

One of the most common selection mistakes is focusing only on whether the valve is single or double solenoid.

In reality, the spool function and neutral position often have a greater impact on machine operation.

For example, a three-position double solenoid directional valve can use different center functions.

Depending on the hydraulic symbol, the center position may:

Block P, T, A and B
Connect P to T while blocking A and B
Connect A and B to T
Connect several ports together
Use another specialized flow arrangement

These different center conditions can affect:

Whether the pump is unloaded
Whether the cylinder is locked
Whether the actuator can float
Hydraulic system temperature
Pressure buildup
Machine safety

Therefore, buyers should always confirm the hydraulic symbol, not just “single head” or “double head.”

Example: Double-Acting Hydraulic Cylinder

Consider a hydraulic cylinder that must extend and retract.

With a single solenoid spring-return valve:

Coil energized → Cylinder extends

Coil de-energized → Spring shifts valve → Cylinder retracts

This is simple and effective if that operating logic is suitable for the machine.

With a double solenoid valve:

Solenoid A → Cylinder extends

Solenoid B → Cylinder retracts

If a three-position valve is used:

Neither solenoid energized → Spool returns to center

The center function can then hold, unload or float the actuator depending on the selected spool.

This provides more control flexibility but requires the correct electrical and hydraulic configuration.

Single vs Double Solenoid for 4WE6 and 4WE10 Valves

Directional valve families such as 4WE6 and 4WE10 are available with many spool functions and operating arrangements.

Customers often describe them simply as:

Single solenoid / single head

Double solenoid / double head

But this information alone is not sufficient for accurate valve selection.

For example, two 4WE6 valves may have the same voltage and mounting size while using completely different spool symbols.

Before replacing a 4WE6 or 4WE10 valve, confirm:

Complete Model + Hydraulic Symbol + Coil Voltage + Spool Function

This is especially important when replacing Rexroth-type, Yuken-type or other standardized industrial directional valves.

Common Selection Mistakes

Several mistakes frequently occur when ordering solenoid directional valves.

Choosing by Appearance

Single and double solenoid valves from the same series may look very similar to other valves with different internal spool functions.

External appearance cannot confirm hydraulic compatibility.

Assuming Double Solenoid Means Three Position

Not necessarily.

Some double solenoid valves use two positions, while others have three positions.

Always check the hydraulic symbol.

Ignoring the Power-Off Condition

Ask what the actuator should do when the electrical signal disappears.

Should it:

Return?
Stop?
Hold position?
Float?
Remain in the last selected position?

This question can significantly narrow down the correct valve configuration.

Selecting the Wrong Coil Voltage

Common voltages include:

DC 12V
DC 24V
AC 110V
AC 220V

The hydraulic function may be correct, but an incorrect coil voltage will prevent normal operation and may damage the coil.

Ignoring the Mounting Interface

The replacement must also match the original mounting standard, valve size and manifold interface.

What Information Should Buyers Provide?

When requesting a replacement directional valve, providing complete information can greatly improve model-confirmation accuracy.

Useful information includes:

Complete valve model
Valve photo
Nameplate photo
Hydraulic symbol
Single or double solenoid
Coil voltage
Connector type
Valve size such as NG6 or NG10
System pressure
System flow
Equipment application
Required quantity

If the original model is unclear, clear photographs of the nameplate, hydraulic symbol, solenoids and bottom mounting surface can be especially helpful.

How to Choose Between Single and Double Solenoid Valves

A simple selection method is to ask four questions.

1. How many controlled spool positions are required?

If the application only requires one energized position and one spring-return position, a single solenoid may be sufficient.

2. What should happen when power is removed?

If the valve must automatically return to a defined condition, a spring-return configuration may be preferable.

3. Does the machine require independent electrical commands in both directions?

If yes, a double solenoid design may provide greater flexibility.

4. What hydraulic center function is required?

For three-position valves, confirm the center condition according to the machine circuit.

The final decision should therefore be based on the complete hydraulic function, not only the number of solenoids.

How XYIYEYA Supports Directional Valve Selection

XYIYEYA supplies solenoid directional valves for industrial equipment, hydraulic power units, machinery repair and replacement applications.

Conclusion

The choice between a single solenoid and double solenoid directional valve depends on more than the number of coils.

A single solenoid valve often provides simple electrical control and automatic spring return when the coil is de-energized.

A double solenoid valve provides greater control flexibility and can be used for bidirectional or three-position hydraulic control.

However, the most important factors are:

Hydraulic Symbol + Spool Function + Neutral Position + Power-Off Behavior + Coil Voltage + Mounting Size

Before ordering a replacement valve, confirm these details carefully.

Selecting the correct configuration helps ensure reliable cylinder or motor control and prevents unnecessary hydraulic system problems.