Fisher 2502-249B Actuator Spring Kit

Technical Specifications

Model：2502-249B Brand：Fisher Product Type: Pneumatic diaphragm actuator spring kit

Module Feature

Fisher 2502-249B is precision compression spring kit designed for Fisher 657/658 series spring-diaphragm pneumatic actuators. The spring defines the actuator bench set pressure range. High tensile spring steel with heat treatment delivers stable elasticity and anti-fatigue performance under repeated cyclic stroke. Widely used in oil,gas,chemical and power plant globe control valve actuators.

Working principle: Counteract diaphragm thrust to balance air pressure and determine valve stroke position Onboard components: Main compression spring, spring retainer plates, locating washers

LED indicators

Not equipped

Hardware self-diagnosis

Visual inspection, crack & fatigue deformation inspection, bench range test after actuator reassembly, stroke linearity test

Programming software

No dedicated software required

Mechanical & Structure

Mounting: Installed inside actuator housing against diaphragm plate Protection class:IP66

Environmental

Operating temperature:-40℃ ~ +120℃ Ambient humidity:5~95% non-condensing Certification:CE Status:Fisher actuator spring spare kit

System compatibility

Compatible with Fisher 657 and 658 series pneumatic diaphragm actuators, paired with globe control valve and FIELDVUE positioner.

Function

2502-249B is actuator spring assembly manufactured by Fisher. It provides opposing spring force against diaphragm pneumatic thrust. The spring characteristic defines the actuator bench range, which determines how instrument air pressure converts to valve stem travel. Spring fatigue, fracture or permanent deformation leads to incorrect bench set, stroke shift and poor valve positioning. It is essential spare part for actuator overhaul.

Installation

Follow lockout/tagout safety procedure before installation. Cut off instrument air supply and release residual air pressure. Disassemble actuator casing, replace old spring assembly. Align spring and retainer plates properly. Reassemble actuator housing, cross-tighten bolts, calibrate bench range and perform full stroke test.

Interface

Preloaded between actuator upper casing and diaphragm plate, no LED indicators on 2502-249B.

Diagnostic

Incorrect bench range: Spring fatigue or permanent deformation. Valve cannot reach full travel: Spring over-stiff or broken. Unstable stroke: Spring misalignment or uneven force.

Product Brief

2502-249B Fisher pneumatic diaphragm actuator compression spring kit,sets bench pressure range for 657/658 actuator,for industrial control valve actuator overhaul and spring replacement,actuator force balancing spare part.