» Fisher™ · Instrumentation
Volume Boosters & Relays
Speed up the valve without losing accuracy — Fisher™ volume boosters deliver rapid air on sharp signal changes for large actuators and fast loops, while holding steady-state precision.
- Faster actuator stroking
- Rapid air on signal change
- Steady-state accuracy held
- Genuine OEM parts
What it is
Speed where the positioner can't keep up
A volume booster (or booster relay) sits between the positioner and the actuator to move air faster than the positioner alone can. When the input signal jumps, the booster opens wide and delivers a large volume of air quickly — stroking a big actuator in a fraction of the time.
An integral bypass restriction lets the positioner keep fine, steady-state control once the valve settles, so you gain speed without sacrificing accuracy. Boosters are essential on large actuators, long supply lines and fast, surge-prone loops.
The line
Fisher™ volume boosters we supply
Genuine Fisher™ boosters and relays. Open each bulletin, or tell us the actuator and response you need and we'll confirm the right one.
Fisher™ 2625
Increases actuator stroking speed on throttling control valves — delivers rapid air volume on sudden signal changes while the positioner keeps its accuracy. Available as 2625, 2625SST and 2625NS.
Fisher™ VBL
Boosts stroking speed for throttling control valves with rapid output on large signal changes, holding steady-state accuracy through an integral bypass restriction and soft-seat construction.
Genuine OEM
Genuine Fisher™ booster spare parts
A booster only delivers its speed-without-drift balance when its diaphragms, soft seats and bypass restriction are right. We supply genuine Fisher™ repair kits, diaphragms, seats and O-rings so a 2625 or VBL keeps stroking fast and settling accurately.
Tell us the actuator size, supply and the response you need — our team will confirm the right Fisher™ booster or genuine parts.
Resources & tools
Spec it, look it up
Each model above links to its Fisher™ bulletin. Here's the rest of what you need to select and support a booster.
Brochure
Protect Your Critical Compressors (PDF)
How fast, accurate final control — boosters included — protects anti-surge and compressor performance.
Download PDF →Free tool
Fisher™ Obsolete & Inactive Lookup
Running a discontinued Fisher™ booster or relay? Find its recommended replacement.
Look it up →Selection guide
Sliding-Stem (Globe) Valve Selection Guide (PDF)
Select the globe or angle control valve the booster will drive.
Download PDF →Selection guide
Rotary Valve Selection Guide (PDF)
Select the rotary control valve — Vee-Ball, eccentric plug, high-performance butterfly.
Download PDF →Need a Fisher™ booster or parts?
Tell us the actuator and response — genuine OEM, shipped from our Orlando, FL warehouse.