The AirTAC Airtac 4V Solenoid Valves 4V31008A-W is a genuine 5/2-way single solenoid (spring return) solenoid valve with W ports and an effective area of 28.0 mm² (Cv 1.65). It is an internally piloted spool valve that directs compressed air to double-acting cylinders and actuators.
The 4V31008A-W is a 5/2-way single-solenoid poppy of the AirTAC 4V300 family sized for 1/4-inch PT ports, built around an AC220V coil (4.5 VA) wired to a terminal box and fitted with the factory -W external-pilot option. With external piloting, the spool is shifted by pilot air supplied through a dedicated external port rather than tapped from the main line, so the valve keeps switching dependably in vacuum lines and circuits where main pressure runs low. Energise the coil and the valve directs air to one side of a double-acting cylinder; cut power and the internal spring snaps it back to the rest position automatically.
Flow-wise this body sits in the 28 mm2 effective-area class (Cv 1.65), which matches double-acting cylinders of roughly 50 to 80 mm bore. The spool reacts in 0.05 s or less and tolerates up to 4 cycles per second, and the whole assembly weighs just 310 g, so it mounts neatly on a manifold base or directly on the machine.
| Model | Airtac 4V Solenoid Valves 4V31008A-W |
|---|---|
| Series | 4V300 solenoid valve (spool type) |
| Valve type | 5/2-way |
| Function | Single solenoid (spring return) |
| Port size | W |
| Exhaust port | W |
| Effective area (Cv) | 28.0 mm² (Cv 1.65) |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Pilot type | Internal / external pilot |
| Operating pressure | 0.15 – 0.8 MPa |
| Proof pressure | 1.2 MPa |
| Max frequency | 4 cycle/sec |
| Response time | ≤ 0.05 s (activating) |
| Temperature | -20 to +70 °C |
| Body material | Aluminum alloy |
| Weight | 310 g |
Specifications follow the official AirTAC 4V series datasheet. Lubrication not required. Confirm coil voltage and thread (PT / NPT / G) against the product label before wiring.
| Effective area | 28.0 mm² |
|---|---|
| Flow coefficient | Cv 1.65 |
| Response time | ≤ 0.05 s |
| Coil power | AC 4.5 VA · DC24V 3.0 W · DC12V 2.5 W |
| Protection / insulation | IP65 (DIN40050), B-class |
| Voltage options | DC24V, DC12V, AC110V, AC220V |
| Manual override | Yes (locking / non-locking) |
Size the valve so effective area / Cv is not the bottleneck for your cylinder bore and speed. Undersized valves slow the actuator. Note 5/3 (center) versions have a smaller effective area than the 5/2 of the same body size.
| 4V | Solenoid valve, spool type, 4-series. |
|---|---|
| 3 | Body size (4V300) — sets port & flow. |
| 1 | Function: 1 = single 5/2, 2 = double 5/2, 3 = 5/3. |
| -W | Port thread: M5 / 06=1/8" / 08=1/4" / 10=3/8" / 15=1/2". |
Related: 4V310 (single), 4V320 (double), 4V330C/E/P (5/3 center). Add the voltage suffix when ordering.
Spring-return shifting makes this valve a natural fit for stoppers and pushers on packaging lines: the cylinder extends only while the AC220V signal is present and retracts the instant power drops.
The -W external pilot keeps spool switching positive even when the main line runs at reduced pressure or in vacuum applications, a common situation on fixture and workholding circuits.
At 310 g with terminal-box wiring, the valve groups cleanly on a 4V300 manifold base alongside other stations, giving machine builders one compact air-control block for multiple double-acting actuators.
Choose this model when your cylinder bore falls in the ~50-80 mm band. A smaller actuator is better served by stepping down to the 4V200 (Cv 1.0); a larger bore calls for the 4V400 (Cv 2.82). Within the 4V300 line, pick the single solenoid (this SKU) when the cylinder must always return to a known rest position on power loss, the double solenoid 4V320 when you need two stable states, or a 4V330 5/3 version when a defined center condition is required. One valve per position works fine; add a manifold base when several stations share one supply.
Replacing an existing unit? Match all five points: body size (4V300), function (5/2 single, spring return), port and thread (1/4-inch PT tapered), coil voltage (AC220V here), and electrical entry (terminal box). Then confirm the -W external-pilot suffix is carried over if your circuit feeds pilot air separately.
Quick checklist
It is a 5/2-way valve with an effective area of 28 mm2 (Cv 1.65), intended for double-acting cylinders and actuators of roughly 50 to 80 mm bore. Single-acting cylinders need a 3/2 valve instead.
The -W option feeds pilot air from a separate external port rather than the main supply, so switching stays reliable in low-pressure or vacuum circuits. Because the valve is single-solenoid with spring return, the spool goes back to its rest position whenever the coil is de-energised, giving a predictable fail-position without a second signal.
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