In the demanding world of process control, the accuracy and reliability of a control valve assembly often hinge on one critical component: the valve positioner. Among the industry’s most respected names, Emerson’s Fisher 3590 series stands out as a robust, high-performance pneumatic positioner. Unlike smart digital positioners, the 3590 is a pneumatic instrument, prized for its simplicity, durability, and intrinsic safety in harsh environments.
However, without access to the official Fisher 3590 valve positioner manual, even seasoned technicians can struggle with proper installation, calibration, or fault diagnosis. This article serves as a comprehensive guide, distilling the essential information from the original manual. We will cover pneumatic principles, mounting procedures, step-by-step calibration, common failure modes, and practical troubleshooting.
Disclaimer: This guide is for informational purposes only. Always refer to the official Fisher (Emerson) instruction manuals (e.g., D103173X012) for your specific device revision before performing any maintenance.
For the 3590 with integral I/P (current-to-pressure) converter, the manual provides three critical specifications often overlooked:
The Fisher 3590 is a pneumatic, force-balance, field-reversible positioner. Its primary function is to compare a pneumatic input signal (typically 3-15 psi or 3-27 psi) with the actual valve stem position. It then supplies or exhausts supply pressure to the actuator to maintain the exact position commanded.
Q1: Can I convert a Fisher 3590 from direct to reverse action without new parts?
Q2: What is the correct air supply pressure for a 3590 on a 6-inch linear valve?
Q3: My manual is missing. Where can I download the official Fisher 3590 positioner manual?
Q4: Does the 3590 support HART or digital communication?
Q5: The manual mentions “characterized cam” options. Which cams are available?
| Part Name | Typical Part Number | |-----------|----------------------| | Range spring (3–15 psi) | 14B5722X012 | | Flapper assembly | GE38721X012 | | Nozzle | 17A9597X012 | | Relay diaphragm | 17A9070X012 |
The Fisher 3590 series is a family of electro-pneumatic and pneumatic valve positioners designed for rotary and sliding-stem actuators. Unlike older analog positioners, the 3590 integrates high-lift cam technology and a robust feedback system. Based on a thorough review of its instruction manual (typically D103172X012), this write-up examines the critical engineering details, setup procedures, and maintenance considerations that a technician or engineer must understand.
The Fisher 3590 valve positioner manual is not merely a set of install instructions—it is a blueprint for achieving ±0.5% position accuracy in pneumatic control loops. By understanding the force-balance principle, following the step-by-step calibration, and respecting the maintenance schedules outlined in the official documentation, you can keep your process valves operating reliably for decades.
Whether you are troubleshooting a hunting valve in a refinery or installing a new unit on a pipeline ESD valve, the key points are: clean air, tight linkage, correct cam orientation, and methodical zero/span adjustment. Always keep a digital or physical copy of the manual nearby, and never guess when a torque spec or a nozzle gap is in question.
Next Steps for Technicians:
This guide is intended to complement, not replace, the original manufacturer’s documentation. All trademarks are property of their respective owners.
The Fisher 3590 is an electro-pneumatic valve positioner designed to receive a DC current input signal (typically 4-20 mA) and convert it into a proportional pneumatic output pressure to control a valve actuator. It is often used to ensure a linear relationship between the control signal and the actual valve position while overcoming friction and process force imbalances. Stewart Instrument Core Specifications Input Signal:
Standard 4-20 mA DC; options for 10-50 mA or split-range operation are available. Output Signal:
Pneumatic pressure as required for valve plug travel, typically between Supply Pressure:
Must be at least 5 PSIG higher than the upper range limit of the input signal. Configurable for both (output increases with signal) or Stewart Instrument Calibration & Adjustment Procedures
Calibration ensures the valve stem reaches the exact position dictated by the control signal. Valve Related Controls Preparation
: Shut off supply pressure and connect necessary tubing from the positioner output to the actuator. Set the input signal to mid-range. Beam Alignment
: Move the flapper assembly to the correct operating quadrant on the beam. Apply supply pressure and ensure the 0 raised to the composed with power
index marks on the rotary shaft arm align with the case marks. Zero Adjustment
: Apply the low-end input signal (e.g., 4 mA or 3 psig). Loosen the nozzle locknut and adjust the nozzle until the actuator reaches the start of its travel. Span Adjustment
: Apply the high-end signal and move the flapper assembly along the summing beam to set the full travel limit. Maintenance & Safety Supply Quality
: The supply medium (air or natural gas) must be clean, dry, and non-corrosive to prevent obstruction of small internal passages.
: Avoid using sealing tape on pneumatic connections, as fragments can clog the unit; use thread sealant paste Safety Warning
: Before maintenance, isolate the control valve from process pressure and disconnect all air, electric, and control signal lines to prevent accidental valve movement. Control Valve Actuators and Positioners - Spirax Sarco fisher 3590 valve positioner manual
Fisher 3590 series of electro-pneumatic valve positioners is an obsolete product line formerly manufactured by Fisher Controls (now part of Emerson)
. Because it is discontinued, the "full paper" or instruction manual is no longer hosted on the main Emerson product pages, but documentation remains available through historical archives and technical resource libraries. Manual Availability
The primary instruction manual for this series is typically found under historical Fisher documentation. Archival Access: You can view or download the manual on the Scribd Archive for Fisher 3590 Alternative Support:
For official legacy support, it is recommended to contact an Emerson Sales Office
directly, as they maintain the "Fishweb" database for obsolete product manuals Key Specifications (3590 / 3590ST)
The 3590ST model was a common variant in this series. Its technical highlights include: Input Signal: 4-20 mA DC (300 Ohms internal resistance) Supply Pressure: Maximum of 50 psi Ambient Temperature: -40° to 150°F (-40° to 65°C) Classification: Class I, Groups B, C, and D (hazardous area certified) Product Status & Maintenance Obsolescence:
These products are no longer manufactured. Recommended spare parts were guaranteed for 10 years after production ended, meaning original parts are now largely sourced through second-hand or specialized industrial surplus retailers Modern Replacement:
For current applications requiring similar functionality, Emerson typically recommends the Fisher DVC6200 series of digital valve controllers or to find a compatible replacement for an existing unit?
The Fisher 3590 (including S and ST variants) is a legacy electro-pneumatic valve positioner series widely regarded for its ruggedness and reliability in harsh industrial environments. While Emerson officially classifies the 3590 as an obsolete product, it remains a staple in secondary markets due to its straightforward mechanical design and high compatibility with existing Fisher control technology. Performance Review
Precision & Speed: This series is praised for providing an output signal directly proportional to the valve stem position, significantly increasing the speed of response compared to using an I/P transducer alone.
Mechanical Feedback: It uses a mechanical feedback linkage (cam-and-beam) that effectively minimizes hysteresis and negates flow-induced reactions, ensuring the valve maintains its setpoint even under high pressure drops.
Operating Range: The 3590ST typically handles a standard 4-20mA input signal with internal resistance around 300 Ohms and can manage supply pressures up to 50 PSI. Pros & Cons
Fisher 3590 is a series of electro-pneumatic valve positioners designed to accurately position a control valve stem in proportion to an electrical input signal. Most commonly used with sliding-stem
actuators, the 3590 series converts a 4–20 mA DC signal into a pneumatic output pressure that drives the actuator. Key Specifications Input Signal 4-20 mA DC, 10-50 mA DC, or split ranges Output Signal Pneumatic pressure required for 7/16 to 4 1/8 inch travel Supply Pressure In the demanding world of process control, the
Typically 5 psi higher than the upper range limit of the input; max usually 50 psi Field-reversible between Direct and Reverse action Operating Principle
The Fisher 3590 operates as a force-balance instrument. The electrical input signal is received by an I/P (current-to-pressure) transducer, which creates a proportional pneumatic signal. This signal acts upon a bellows or diaphragm assembly that moves a beam. As the beam pivots, it changes the relationship between a nozzle and a flapper, modulating the relay output pressure to the actuator. Feedback from the valve stem is provided through a range spring, ensuring the valve reaches the exact commanded position. Maintenance & Safety Guidelines Pressure Release:
Always disconnect operating lines (air pressure and electric power) before performing maintenance to prevent sudden movement or pressure release. Air Quality:
Use a clean, dry, and oil-free air supply. Contaminants can plug pneumatic lines or damage internal components like O-rings and diaphragms.
The 3590 is typically mounted on the actuator using a specific mounting bracket and feedback linkage. Correct alignment of the stem feedback is critical for calibration. Troubleshooting:
Common issues include calibration drift or plugged nozzle/flapper assemblies. If the positioner fails to respond, check for debris in the air supply or a faulty I/P converter.
The Fisher 3590 is a discontinued series of electro-pneumatic valve positioners. While Emerson (Fisher's parent company) has moved most legacy manuals to archival status, the technical details for the remain available for maintenance and replacement purposes. 🛠️ Key Technical Specifications
The Fisher 3590 series converts a DC current signal into a pneumatic output pressure to precisely position a control valve plug. Input Signal: 4-20 mA DC, 10-50 mA, or split-range options.
Supply Pressure: Typically 5 PSIG higher than the upper range limit of the input signal, with a maximum of approximately 50 PSI.
Travel Range: Supports valve plug travel from 7/16 to 4 1/8 inches. Action: Available in both Direct or Reverse action.
Compliance: Often rated for ATEX Group II (Gas and Dust) hazardous areas. 📖 Manual & Documentation Resources
Since this is an obsolete product, you may find the full instruction manuals on third-party technical libraries or specialized surplus sites:
Official Emerson Archive: Check the Discontinued Products section for official legacy documentation.
Scribd Technical Library: The complete Instruction Manual Form 5370 for Types 3590, S, and ST is hosted on Scribd. Disclaimer: This guide is for informational purposes only
Commercial Support: Sites like Radwell provide limited technical data and repair services for these units. ⚙️ General Maintenance & Calibration
Calibration typically follows a "Force-Balance" principle common to analog Fisher positioners: