Key Technical Specifications
- Product Model: 8402-271
- Manufacturer: WOODWARD
- Product Type: Gas Control Valve Actuator
- Coil Voltage: 24VDC
- Valve Configuration: 3-Way Pneumatic Pilot
- Mounting Type: Flange / Bracket Mount
- Operating Medium: Instrument Air / Nitrogen
- Operating Pressure: 60–150 PSIG (verify with manual)
- Response Time: < 50ms (typical)
- Temperature Range: -40°F to +185°F (-40°C to +85°C)
Product Introduction
The WOODWARD 8402-271 is a 3-way solenoid actuator used as a pneumatic pilot valve in gas turbine fuel control systems. It converts an electrical signal from the turbine controller into precise pneumatic movement to position the main gas control valve.This actuator provides fast response (under 50ms typical) and reliable 3-way pilot operation for fuel metering applications. The 24VDC coil is standard across many turbine platforms, making it a common field-replaceable component. (I should note that coil resistance varies by revision — always measure before assuming it matches your system.)
Installation & Configuration Guide
Preparation (10 min)
Lock out and tag out the turbine control power. Verify 24VDC supply is isolated. Gather tools: 7/16″ wrench, multimeter, clean lint-free wipes. Confirm the replacement 8402-271 matches the nameplate on the existing unit.Removal (5–10 min)
Disconnect the electrical connector first. Label supply, exhaust, and output air lines before disconnecting. Remove the two mounting bolts. Inspect the gasket surface — replace the gasket if it shows compression set or tears.Installation (10 min)
Position the new actuator with a fresh gasket. Torque mounting bolts to 15–20 in-lbs (do not overtighten). Reconnect air lines per your labels. Reconnect the electrical plug. Double-check that no wires are pinched.Power-On & Test (10 min)
Restore 24VDC power. Energize the coil and verify the actuator shifts fully within 50ms. Check for air leaks at all connections. Run a manual stroke test through the controller to confirm full travel. (If the valve sticks, check for moisture in the air supply before blaming the actuator.)
Troubleshooting Quick Reference
| Symptom | Probable Cause | First Check |
|---|---|---|
| No movement | No coil power | Measure 24VDC at connector |
| Slow response | Air supply low | Verify supply ≥ 60 PSIG |
| Air leak at base | Gasket failure | Replace gasket, re-torque |
| Intermittent operation | Loose connector | Reseat plug, check pin tension |
| Coil burns out | Overvoltage | Measure actual supply voltage |
Dimensions, Mounting & Wiring Notes
- H × W × D: 4.5″ × 3.0″ × 2.8″ (approximate — verify with OEM drawing)
- Mounting: Two-bolt flange, 2.38″ bolt circle
- Terminals: Molex-style plug, pin A = positive, pin B = negative
- Air Ports: 1/8″ NPT (supply), 1/8″ NPT (exhaust), 1/8″ NPT (output)
- Wiring Note: Use 18 AWG minimum. Keep wiring away from VFD cables.
FAQ
Is the 8402-271 compatible with my Mark V controller?
Most likely yes, but verify the coil voltage and pinout against your specific Mark V I/O card documentation. Revisions matter here.I got a unit that looks different from my old one. Is it wrong?
Woodward has issued multiple revisions of the 8402-271 over the years. External appearance can change while function remains identical. Check the nameplate part number and revision letter, not just the casting.What happens if I install it without replacing the gasket?
You risk an air leak at the base that won’t show up until the valve shifts under pressure. Always use a new gasket. It takes 30 seconds and prevents a callback.Do you test these before shipping?
Yes. Each unit goes through incoming inspection, live functional testing on a dedicated pneumatic test rack, coil resistance verification, and a 24-hour load test. A test report is included. Function is verified under test conditions — we do not guarantee field performance since that depends on your installation.Can I use this for steam service instead of gas?
No. This actuator is designed for instrument air or nitrogen pilot duty. Steam service requires different seals and materials. Using it for steam will cause premature failure.How long does shipping usually take?
Refurbished units typically ship within 2–3 business days. New surplus ships same day if in stock. Expedited options are available — just ask.I wired it backwards and now it doesn’t work. Did I fry it?
Possibly. Reverse polarity on a 24VDC coil can damage internal electronics. Measure coil resistance — if it reads open or significantly out of spec, the coil is damaged. This is not covered under warranty.
