Fisher 3590 Valve Positioner Manual May 2026

A very specific and technical topic!

Do you have any specific questions or aspects you'd like to discuss regarding the Fisher 3590 valve positioner manual?

Do not lubricate the feedback shaft. The manual says dry nylon bushings are correct—lubrication attracts dirt.

Use the plastic gauge block (supplied) to set the initial flapper-nozzle gap. Eyeballing it causes 5-10% zero shift.

Replace the O-rings inside the pneumatic cover every 2 years. The manual lists a kit (part 3590K1A) that includes the exact Viton compound for process temperatures up to 250°F.

Always mount with the vent pointing downward. The manual is emphatic: a horizontal vent will collect rain or washdown water, corroding the internal spring.

Output Pressure: Pneumatic pressure sufficient for 7/16 to 4 1/8 inch valve travel.

Valve not responding: Check air supply, valve connection, and positioner settings.

Incorrect valve positioning: Adjust zero and range settings, or check for worn or damaged parts.

A very specific and technical topic!

Do you have any specific questions or aspects you'd like to discuss regarding the Fisher 3590 valve positioner manual?

Do not lubricate the feedback shaft. The manual says dry nylon bushings are correct—lubrication attracts dirt.
Use the plastic gauge block (supplied) to set the initial flapper-nozzle gap. Eyeballing it causes 5-10% zero shift.
Replace the O-rings inside the pneumatic cover every 2 years. The manual lists a kit (part 3590K1A) that includes the exact Viton compound for process temperatures up to 250°F.
Always mount with the vent pointing downward. The manual is emphatic: a horizontal vent will collect rain or washdown water, corroding the internal spring.

Output Pressure: Pneumatic pressure sufficient for 7/16 to 4 1/8 inch valve travel.

Valve not responding: Check air supply, valve connection, and positioner settings.
Incorrect valve positioning: Adjust zero and range settings, or check for worn or damaged parts.