Fisher Control Valve Decoder Guide

Fisher Is an Assembly, Not a Model Code

Where a Rosemount 3051 tag is one model string against one PDS, a Fisher control valve tag is a kit of parts. A maintenance planner walking up to an installed control valve will see a nameplate on the body, a different nameplate on the actuator, and a third nameplate on the positioner. Each of those nameplates names a separate Emerson bulletin: 51.1:ED for the body, 61.1:657 Size i for the actuator, 62.1:DVC6200 for the positioner. The 627 Series regulators have their own bulletin (71.1) and are typically a separate device on the loop rather than part of a control-valve assembly.

This matters because the most safety-critical decode question on Fisher tags is fail action. Fail action depends on both the body plug action AND the actuator action. If a planner reads just the actuator nameplate (657) and concludes "fail open," and the body underneath happens to be an EDR (push-down-to-open), the assembly actually fails closed and the planner just installed a CV in the wrong fail direction. The decoder enforces this by refusing to derive fail action without both pieces of data.

The four V1 component classes are: valve body (the pressure-containing part with the trim), actuator (the air-loaded mechanism that strokes the stem), instrument or positioner (the smart device that takes 4-20 mA or HART and modulates supply pressure to the actuator), and regulator (the self-contained pressure-reducing device for instrument-air supply or natural-gas service). The decoder builds a four-card grid showing all four classes, and empty cards explicitly say "Add this component to your tag string for a full assembly decode."

The easy-e Valve Body Family Map

The easy-e family is the workhorse Fisher globe body. Four sub-families are in V1 scope and they differ on three axes: guiding style (cage-guided vs post-guided), plug balance (balanced vs unbalanced), and shutoff capability.

• ED / EAD / EDR - balanced, cage-guided. ED is the straight-through globe (push-down-to-close), EAD is the angle version of ED, EDR is the push-down-to-open variant. NPS 1 through 8 for ED; EAD and EDR have narrower envelopes per Table 2 of the ED bulletin. Multi-stage Whisper Trim III, Whisper NXG, WhisperFlo (NPS 4 and 6 ED only), and C-seal trim (Class V high-T) are all available.
• ET / EAT / ETR - balanced, cage-guided, with PTFE seating standard for tighter shutoff. ET is push-down-to-close, EAT is the angle version, ETR is push-down-to-open. PTFE soft seat enables Class VI shutoff per ANSI/FCI 70-2. Cavitrol III (one-stage and two-stage) anti-cavitation trim is available in NPS 1 through 8 ET only, with flow strictly DOWN and thermal limits per Table 9.
• ES / EAS - unbalanced, cage-guided. ES is push-down-to-close, EAS is the angle version. Smaller body envelope than ED, with NPS 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 4, 6, 8 available; EAS is NPS 1, 2, 3, 4, 6 only. Whisper Trim I is available except on NPS 8 ES.
• EZ - unbalanced, post-guided. NPS 1/2 through 4, push-down-to-close. The post-guided design tolerates non-lubricating fluids, viscous fluids, and entrained solids better than cage-guided bodies because the process fluid flows around the post and flushes deposits. The guide-bushing material (Alloy 6 is a common pick) must be matched to the fluid lubricity or the unbalanced plug will gall and seize. Micro-Form, Micro-Flute, and Micro-Flow plugs are available for low-flow service but they have very tight clearances and act as strainers.

The flow direction defaults differ across families and that catches people. ED standard cage is normally DOWN; ED with Whisper or WhisperFlo cage is always UP. ETR standard cage is normally UP; ETR with Whisper Trim cage is always DOWN. EZ flow is always UP through the seat ring (the only family where flow direction is fixed regardless of trim). The decoder surfaces the per-variant flow direction in the Flow directions fact group.

The Fail-Action Matrix: Why You Need Both Sides

Bulletin 61.1:657 Size i pages 2-3 spells it out: a 657 is direct-acting and the spring forces the stem UPWARD on air loss; a 667 is reverse-acting and the spring forces the stem DOWNWARD on air loss. Direction of stem travel on air loss alone does not tell you whether the valve fails open or closed. That depends on the body.

On a push-down-to-close body (ED, EAD, ET, EAT, ES, EAS, EZ), the stem-down direction closes the valve. On a push-down-to-open body (EDR, ETR), the stem-down direction opens the valve. Combining the two:

The most common field mistake is to read the actuator (657) and assume the assembly fails open without checking the body. If the body is an EDR or ETR, that assumption is wrong, and the assembly fails CLOSED. The decoder derives fail action only when both inputs are present in the input string, with status "requires_more_info" otherwise. Page-level citations to both source bulletins (the body bulletin for plug action and the actuator bulletin for actuator action) accompany the derived fact.

One practical heuristic that does NOT replace the matrix: if you see a 657 actuator on what you think is an ED body, the most likely fail action is open. If you see a 667 on what you think is an ED body, the most likely fail action is closed. EDR and ETR exist for a reason - usually because the original spec called for fail-closed in a service where the body needed to be reverse-action (often for self-draining geometry). If you see an EDR or ETR, question whether the original spec was right before swapping in a replacement actuator.

Shutoff Classes (ANSI/FCI 70-2) by Trim Style

ANSI/FCI 70-2 (and the equivalent IEC 60534-4) defines six leakage classes for control valve seats:

• Class I: no test required (manufacturer discretion).
• Class II: 0.5% of rated Cv leakage allowed.
• Class III: 0.1% of rated Cv allowed.
• Class IV: 0.01% of rated Cv allowed (typical metal-seat default with high seat load).
• Class V: water test at 0.0005 ml/min per inch of port per psi differential (high-T metal-seat or soft-seat).
• Class VI: bubble-tight (soft seat - PTFE, PEEK, or elastomer).

Per the bulletins:

• ED standard cage: Class II standard with single graphite ring (ports 33-203 mm); Class III with single graphite piston ring (port >= 87 mm); Class IV with multiple graphite piston rings (port >= 111 mm); Class V high-T with optional C-seal trim (port 73-203.2 mm, up to 593 C / 1100 F).
• ET: Class IV, V, or VI standard. Class V soft-seat ENVIRO-SEAL plus PEEK anti-extrusion rings extends ET above 232 C (450 F): 316 C (600 F) non-oxidizing service or 260 C (500 F) oxidizing service.
• ES: Class IV standard (metal); Class V optional (metal); Class VI with PTFE composition seating.
• EZ: Class IV standard (metal); Class V and VI optional (metal); Class VI with PTFE composition seating.

The trade-offs to watch: Class VI almost always requires a soft seat (PTFE / PEEK / elastomer), and soft-seat temperature limits cap the achievable temperature. PTFE seats are limited to about 232 C (450 F) without anti-extrusion rings; PEEK extends to 316 C (600 F) non-oxidizing or 260 C (500 F) oxidizing. Above those, you must drop to metal-to-metal Class V. Cavitrol III on ET uses metal seating by default and has its own thermal-limit table on bulletin page 10.

Severe-Service Trim: Whisper, WhisperFlo, Cavitrol, C-Seal

Severe-service trim families show up in the bulletins as cage variants that replace the standard quick-opening / linear / equal-percentage cage. They each solve a specific problem:

• Whisper Trim I / III / NXG - aerodynamic noise attenuation in gaseous service. Multi-stage drilled-hole cages drop the pressure incrementally so the velocity at each stage stays subsonic. Always flow UP on ED and ET. Available across the easy-e family; Whisper Trim I is NOT available on NPS 8 ES. Whisper III has its own port / travel table (Table 12 on ED p.22, not Table 11).
• WhisperFlo - linear-only multi-stage cage optimized for gas service noise reduction. Only available on NPS 4 and 6 ED bodies. Other ED sizes and other family members do not get WhisperFlo. The decoder explicitly flags any other size or family that claims WhisperFlo as a special construction requiring Emerson sales-office verification.
• Cavitrol III (one-stage and two-stage) - anti-cavitation trim for liquid service. Drops pressure incrementally on the liquid side so it never reaches vapor pressure and cavitation bubbles never form. Cavitrol III is available only in NPS 1 through 8 ET valves. Flow direction is strictly DOWN. Thermal limits per Table 9 (above). DO NOT install Cavitrol III backward; it bypasses the cavitation control geometry and destroys the trim within days.
• C-seal trim (ED only) - metal-to-metal Class V shutoff up to 593 C (1100 F) using a formed C-seal made of N07718 nickel alloy. Available on ED with port diameters 2.875 in through 8 in. C-seal trim is fragile during installation and must NOT be reused once torqued; order a new C-seal for every maintenance cycle that involves trim removal.
• DST / DST-G dirty-service trim - ET NPS 3-8 and EAT NPS 4-6 for severe-service coker, catalyst, and slurry duty. Has its own Table 10 on the ET bulletin with specific thermal and stage-count limits (V2 data extraction work; not in V1 scope).

NACE Compliance and ENVIRO-SEAL Packing

Two compliance dimensions matter in Fisher CV planning: NACE for sour-service material compatibility, and EPA Method 21 / ISO 15848-1 for fugitive-emission packing.

NACE: every easy-e body bulletin lists NACE MR0175-2002 as the default reference unless otherwise noted, with optional materials available for NACE MR0103 (refining downstream) and NACE MR0175 / ISO 15156 (upstream production and pipelines). Two things to remember: material requirements vary by edition and year of issue, so the exact NACE standard year must be specified, and MR0175 ⊃ MR0103 on hardness (any MR0175-compliant material passes MR0103 by definition, but not the other way around). The standard Fisher hardened CoCr-A overlays (typical of severe-service trim) are NOT NACE-compliant by default; sour-service applications require explicit material substitution.

ENVIRO-SEAL packing: Fisher's low-emission packing family meets EPA Method 21 below 100 ppm fugitive emissions. Available in PTFE, Graphite ULF, or Duplex variants with live-loading via belleville washers. Pressure / temperature limits per bulletin: ENVIRO-SEAL PTFE or Duplex are good to full CL300 up to 232 C (450 F); ENVIRO-SEAL Graphite ULF reaches 104 bar (1500 psig) at 316 C (600 F). HIGH-SEAL Graphite ULF (live-loaded spring-pack) goes beyond ENVIRO-SEAL limits for non-emission-restricted high-pressure / high-temperature service.

The most common ENVIRO-SEAL field mistake is over-tightening the packing-flange nuts during install. The belleville washers must stay slightly compressed (not flattened) to maintain live-loading. Flattened washers lose the spring force and the packing leaks fugitive emissions during thermal cycling. If the bonnet has been disassembled, the belleville washer stack should be inspected and replaced rather than reused.

The ENVIRO-SEAL bellows seal bonnet provides zero-emission stem sealing but derates the body pressure rating. A CL600 body with a bellows seal bonnet is typically derated closer to CL300 at elevated temperatures. The decoder surfaces this in the bonnet styles fact group and in the field notes.

DVC6200 FIELDVUE: The Instrument Layer

The DVC6200 FIELDVUE is a HART-communicating digital valve controller that converts a 4-20 mA control signal into a pneumatic output to the actuator. It is the dominant instrument layer for modern Fisher control valves. Key facts from bulletin 62.1:DVC6200:

• Communication: HART 5 or HART 7. Pre-HART-7 hosts can usually still poll HART 7 devices in HART 5 mode.
• Input: 4-20 mA DC, nominal point-to-point. Minimum voltage at terminals 9.5 VDC analog or 10 VDC for HART communication. Minimum control current 4.0 mA.
• Output: pneumatic, up to full supply pressure. Maximum output span 9.5 bar (140 psig). Action options are Double, Single Direct, or Single Reverse.
• Supply: 0.3 bar (5 psig) above maximum actuator requirement minimum; 10.0 bar (145 psig) maximum, or the actuator rating, whichever is lower. Supply medium is air or natural gas; clean, dry, noncorrosive per ISA 7.0.01.
• Operating temperature: -40 to 85 C (-40 to 185 F) standard; -52 to 85 C with Extreme Temperature option using fluorosilicone elastomers.
• Mounting: integral to 657/667 spring-and-diaphragm actuators, integral to rotary actuators, sliding-stem linear, quarter-turn rotary, or remote-mount via the DVC6205 base unit and DVC6215 feedback unit pair.
• Position feedback: linkage-less non-contact magnetic sensor. No mechanical linkage to wear or bend. The magnet assembly must be aligned with the Fisher alignment tool or the Hall-effect sensor housing on the back of the DVC can be damaged if the magnet strikes it during stroke.

Hazardous-area approvals are construction-specific. The DVC6200 carries CSA (intrinsically safe, explosion-proof, Division 2, dust ignition-proof - Canada), FM (intrinsically safe, explosion-proof, non-incendive, dust ignition-proof - United States; Type 4X / IP66 enclosure), ATEX (intrinsic safety, flameproof, Type n, dust by intrinsic safety; IP66), and IECEx (intrinsic safety, flameproof, Type n, dust by intrinsic safety or by enclosure; IP66) approvals - but not all approvals apply to all constructions. The bulletin page 5 approvals table is the source of truth for which combination applies to which construction. The decoder surfaces this caveat on every DVC6200 decode.

The 627 Series Regulator: A Separate Branch

The 627 Series direct-operated pressure-reducing regulators are a separate product line from the control-valve assembly. They appear on a CV loop only as the instrument-air supply regulator (drops plant air to the DVC6200 supply pressure) or in natural-gas / fuel-gas service as a stand-alone pressure-reducing device. The 627 portfolio has 12 type variants per bulletin 71.1:

• 627 - base direct-operated reducing regulator.
• 627H - high-pressure version (diaphragm limiter).
• 627M - external pressure registration (stem seal between body outlet and diaphragm case; pressure measured through 1/4 NPT downstream control line).
• 627BM - balanced trim plus stem seal (higher flow rates, higher inlet pressure ratings; bubble-tight shutoff at 1000 psig inlet with NBR disk).
• 627HM - 627H with stem seal.
• 627BHM - 627BH with stem seal.
• 627R - internal relief and open throat.
• 627LR - 627R with light rate relief spring (very low flow / very narrow outlet pressure ranges, only the 15-40 psig Green spring).
• 627MR - 627M with internal relief.
• 627BMR - 627BM with internal relief.
• 627OSX - 627 with Type OSE slam-shut device for overpressure protection.
• 627BMOSX - 627BM with OSE slam-shut device.

Body sizes are 3/4 NPT, NPS 1 / DN 25, NPS 1-1/4 / DN 32, and NPS 2 / DN 50. End connections: NPT, CL150 RF, CL300 RF, CL600 RF, PN 16/25/40, BWE, and Long Body NPT (627 Long Body has the same face-to-face dimensions as the Type 630). Body materials: ductile iron (NOT available for 627H or 627HM), WCC steel (required for 627H/HM/BHM), LCC steel, and stainless steel (available only for 627, 627R, 627H).

Outlet pressure ranges are coded by spring color: Yellow (5-20 psig / 0.34-1.4 barg), Green (15-40 psig / 1.0-2.8 barg), Blue (35-80 psig / 2.4-5.5 barg), Red (70-150 psig / 4.8-10.3 barg). High-pressure variants (627H/HM/BHM) use Blue HP (140-250 psig) and Red HP (240-500 psig).

EPA Quad Oa for natural-gas service: standard-bleed 627 regulators continuously bleed gas to atmosphere. This is acceptable for instrument-air supply but NOT compliant for new natural-gas / fuel-gas installations under EPA Quad Oa (40 CFR Part 60 Subpart OOOOa). For new natural-gas service, specify a low-bleed or non-bleeding variant. Existing standard-bleed installations may be grandfathered. The decoder surfaces this in the regulator field notes.

Worked Example: Fisher ET 667 DVC6200 NPS 4 CL300

A maintenance planner picks up a tag during a turnaround walk-down that reads "Fisher ET 667 DVC6200 NPS 4 CL300". Walk through the decode:

1. Tokenize: [Fisher, ET, 667, DVC6200, NPS, 4, CL300]. "Fisher" is stripped as a marketing word.
2. Identify components: ET (easy-e ET / EAT / ETR valve body family); 667 (reverse-acting actuator); DVC6200 (FIELDVUE digital valve controller). Three components, all valid V1 identifiers.
3. Attach hints: "NPS 4" is a size hint - the kind-aware router places it on the ET body (size hints prefer valve_body). "CL300" is a pressure-class hint - also routed to the ET body. Both reconcile as "matches bulletin" because ET supports NPS 4 (per Table 3 on ET bulletin p.5) and CL300 (per ASME B16.34, listed in the End Connection Styles fact group).
4. Derive fail action: ET is push-down-to-close (PDTC) per bulletin 51.1:ET p.3. 667 is reverse-acting per bulletin 61.1:657 Size i p.3. PDTC body + reverse-acting actuator = stem goes DOWN on air loss = valve CLOSES on air loss = fail-CLOSED. The derived fact carries citations to both source pages.
5. Mount compatibility: The decoder also surfaces the actuator-to-instrument mount fact. 667 Size i actuators integral-mount to the DVC6200 (eliminates the traditional bracket per bulletin 61.1:657 Size i p.3). Compatible.
6. Verification checklist: Surfaces body-specific items (pressure / temperature, trim style for noise / cavitation, shutoff class against trim and seat, NACE compliance, packing arrangement, bonnet style), actuator-specific items (thrust adequacy, supply pressure consistency), and instrument-specific items (hazardous-area approval and construction, mounting kit, HART version compatibility).
7. Result: "Decoded a Fisher ET easy-e valve body (push-down-to-close), a Fisher 667 reverse-acting spring-and-diaphragm actuator, and a Fisher DVC6200 digital valve controller. Derived fail action: fail-closed."

If the same planner instead picks up a tag that reads "Fisher EDR 657 DVC6200 NPS 4 CL300", the decode flips: EDR is push-down-to-open per bulletin 51.1:ED p.3, and 657 is direct-acting. PDTO body + direct-acting actuator = stem goes UP on air loss = valve CLOSES on air loss = fail-CLOSED again. Same fail direction, completely different mechanical setup. The decoder is the only way to read these two tags side by side and not get confused about which one has the EDR.