3C2 vs. 3C4 Hydraulic Solenoid Valves: What’s the Real Difference?

3C2 vs. 3C4 Hydraulic Solenoid Valves: What’s the Real Difference?

In the world of hydraulic control, the spool function (or "neutral position") of a solenoid valve determines how fluid behaves when the valve is not energized. Two of the most common configurations are the 3C2 and 3C4 spool types.

While they may look identical on the outside, choosing the wrong one can lead to system drift, pressure spikes, or even equipment damage. As specialists in hydraulic manufacturing with over 9 years of expertise, YHDE breaks down these differences to help you optimize your system performance.

1. The 3C2 Spool: "Closed Center" Function

The 3C2 type is often referred to as a closed-center spool.

• Neutral Position: When the valve is in neutral, all four ports (P, T, A, and B) are blocked.

• Best For: Applications where the actuator (cylinder or motor) must stay locked in position. It prevents "drifting" by trapping oil in the lines.

• Note: Because port P is blocked, the pump pressure will build up to the relief valve setting unless a variable displacement pump is used.

2. The 3C4 Spool: "Float Center" (H-Type) Function

The 3C4 type is known as a float-center or P-blocked, A/B to T configuration.

• Neutral Position: Port P (Pump) is blocked, but ports A and B are connected to T (Tank).

• Best For: Systems where the actuator needs to be "free-wheeling" or in a "float" state when not in use.

• Safety Advantage: Since A and B are connected to the tank, any residual pressure in the cylinder is bled off, allowing for manual movement or preventing thermal expansion issues.

Technical Comparison Table