- Automation & ControlView all 1,652 products
- AC Drives
- Industrial Communications
- PLC & I/O Cards
- Vibration Monitoring
- Automation Accessories
- Controllers & Data Acquisition
- CCTV & Security
- Safety Switches & Guard Locking
- Encoders
- Industrial Computers
- Servo Drives
- Isolator & Barrier
- Motor Soft Starters
- HMI Displays
- Pneumatic Cylinders
- Automation Software
- Machine Vision
- Robotics
Brand: Fisher
Fisher CS800 Commercial/Industrial Pressure Regulator
Description
Fisher CS800 commercial and industrial pressure reducing regulator
The Fisher CS800 series is a direct-operated, spring-loaded gas pressure reducing regulator family for commercial and industrial service. Bulletin D103140X012 (June 2026) groups the base CS800 with variants that add integral protection: the CS803 with True-Monitor protection, the CS804 with an integral Type VSX8 slam-shut module, and CS805 and CS806 with Secondary Seat protection, plus the CS820 and CS850 families for higher outlet ranges.
Seven Star LLC supplies the Fisher CS800 series in Oman and the GCC as an independent supplier in Muscat. Because the type number encodes the outlet range, protection module, registration and relief option, the exact code must be agreed from your process data before quotation.
Decoding the CS8xx type number
The bulletin builds the type number in this order: CS8, then outlet pressure construction, then overpressure protection module, then registration, then relief.
| Position | Meaning |
|---|---|
| Third digit | 0 = low pressure (3.5 to 30 in. w.c. / 9 to 75 mbar); 2 = medium (1 to 5.5 psig / 69 mbar to 0.38 bar); 5 = high (5 to 10 psig / 0.34 to 0.69 bar) |
| Fourth digit | 0 = none; 3 = integral True-Monitor; 4 = slam-shut; 5 = Secondary Seat; 6 = Secondary Seat with controlled bleed |
| Registration letter | I = internal; E = external |
| Relief letter | N = non-relieving; R = internal relief; Q = high-capacity relief; T = token relief; L = low-flow token relief; SC = stabilizer cartridge |
Example from the bulletin: CS800IR is a CS800 without protection module, with internal registration and internal relief.
Fisher CS800 technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Fisher (Emerson) / CS800 Series (Bulletin D103140X012) |
| Emergency inlet pressure | 175 psig / 12.1 bar |
| Outlet pressure range | 3.5 in. w.c. to 10 psig / 9 mbar to 0.69 bar |
| Emergency outlet (casing) pressure | 15 psig / 1.0 bar; 3 psig / 0.21 bar differential above setting to avoid internal damage |
| Temperature capability | -20 to 150 °F / -29 to 66 °C (tested for lockup, relief and reseal to -40 °F) |
| Body sizes and ends | 1-1/4, 1-1/2 and 2 in. NPT; 2 in. Rp; 2 in. / DN 50 flanged CL125 FF, CL150 FF or RF, PN 10/16 |
| Body materials | Gray cast iron, ductile iron, WCC steel |
| Inlet rating by body | Gray iron 175 psig / 12.1 bar; ductile iron 250 psig / 17.2 bar; steel 290 psig / 20 bar (PN 10/16 flanges 232 psig / 16 bar) |
| Orifice sizes | 1/4 to 1-3/8 in. (6.4 to 35 mm); 1/4 in. orifice Cg 50, 1-3/8 in. Cg 1125 |
| Spring case vent | 1 NPT (internal relief); 2-1/2 NPT (high-capacity relief) |
| External registration connection | 3/4 NPT |
| Accuracy capability | Fixed Factor / Pressure Factor Measurement (PFM) |
| True-Monitor performance | Max operating inlet up to 125 psig / 8.6 bar; outlet 12 in. w.c. to 7.5 psig |
| VSX8 slam-shut | Maximum and operating inlet 175 psig / 12.1 bar |
| Hydrogen | Up to 25% hydrogen blend by volume; 100% hydrogen construction available by contacting the factory |
| Soft parts | Nitrile (NBR) diaphragm, disk and body O-ring; aluminum casings |
| Approximate weight (threaded) | CS800 25 lb / 11 kg; CS803 34 lb / 15 kg; CS804 31 lb / 14 kg; flanged body adds 11 lb / 5 kg |
How the CS800 regulates and protects the outlet
The CS800 is a direct-operated regulator: a control spring pushes the diaphragm, and downstream pressure acts on the diaphragm through registration. When the outlet falls, the spring opens the disk; when it rises, the disk closes. Flow-optimized disks are meant to give the most capacity for the application, and only standard tools are needed to adjust pressure and remove the orifice.
Overpressure protection is selected by the fourth digit. True-Monitor places a second, balanced-port actuator in series so that a failed working stage is backed by the monitor, and the bulletin quotes a 125 psig operating inlet for that module. The VSX8 slam-shut closes completely on overpressure and, depending on set-up, underpressure. Secondary Seat adds a second sealing path, and the controlled-bleed version signals that it is working. An optional stabilizer cartridge improves stability.
Fisher CS800 selection and ordering checklist
- Outlet range and construction digit (low, medium or high pressure) against the spring ranges, which run from 3.5 to 6 in. w.c. up to 5 to 10 psig.
- Protection module: none, True-Monitor, slam-shut or Secondary Seat.
- Registration (internal or external) and relief option (none, internal, high-capacity, token or low-flow token).
- Body size and end connection, then body material against inlet pressure rating.
- Orifice size from Table 3: the maximum operating inlet falls from 125 psig for small orifices to 15 psig for the 1-3/8 in. orifice at optimum performance setpoints.
- Low inlet option for the 2 in. body with the 5.5 to 8.5 in. w.c. spring where inlet pressure is low.
- Hydrogen blend requirement, if any.
- Orientation of vent and body, noting that some spring ranges need the spring case pointing downward.
Installing and servicing the Fisher CS800
Install the regulator on clean, filtered gas with the vent pointing down or screened so water and insects cannot enter. Keep any relief vent piped to a safe location according to site rules. Simplified maintenance is a design aim: pressure is adjusted with standard tools, and the orifice can be removed without special equipment. After service, set the outlet with a gauge, lock up the downstream, and check that relief or slam-shut points match the bulletin tables.
Spares worth stocking are diaphragms, disks, O-rings and the control spring in the range you use; the bulletin lists spring part numbers and colors for each range, for example GE30337X012 for 3.5 to 6 in. w.c. and GE30344X012 for 5 to 10 psig.
Typical applications in Oman and the GCC
The CS800 is positioned by its maker for commercial and industrial gas pressure reduction, typically the last stage between a distribution or supply line and burners, boilers and process equipment. In Oman and the GCC that points to factory estates, food and beverage plants, hospitality kitchens and utility fuel gas lines. Hot, dusty conditions call for vent screens kept clear and for protecting regulators from standing water in wash-down areas.
Fisher CS800 variant reference
| Type | Role | Protection |
|---|---|---|
| CS800 | Base regulator, low outlet range (3.5 to 30 in. w.c.) | none |
| CS850 | Base regulator, high outlet range (5 to 10 psig) | none |
| CS820 | Medium outlet range, 1 to 5.5 psig | none |
| CS803 / CS823 | Integral True-Monitor | Monitor module |
| CS804 / CS824 / CS854 | Integral VSX8 slam-shut | Slam-shut |
| CS805 / CS825 | Secondary Seat | Second seal |
| CS806 / CS826 | Secondary Seat with controlled bleed | Second seal, bleed indicator |
Information to send with a Fisher CS800 RFQ
- Full type number or nameplate photo (type, maximum outlet pressure and spring range).
- Gas type, inlet range, set pressure and peak flow.
- Body size, material and connection.
- Protection and relief needs, and hydrogen content.
- Quantity and spare parts.
Documents and quotation
A datasheet for the CS800 series is attached on this page. Please check the type digits there against your required configuration.
Send the CS800 type number and process data to Seven Star LLC in Muscat and we will quote against the confirmed code.
Datasheets & Documents
- Datasheet Fisher CS800 Series Datasheet Download
Reviews (0)
About brand
Fisher is the control valve brand of Emerson. Its history starts in 1880 in Marshalltown, Iowa, where William Fisher, working at the town waterworks, invented a constant-pressure pump governor and founded a company to make it. Emerson bought Fisher Controls in 1992, and Marshalltown remains a main engineering and manufacturing site for Fisher valves. The brand covers control valves, actuators, FIELDVUE digital valve controllers, regulators and level controllers.
Seven Star LLC is an independent supplier listing Fisher control valves, actuators, positioners, regulators and spare parts for buyers in Oman and the GCC. Replacement valves and trim are matched from the serial number on the valve nameplate.
Fisher company profile
| Origin | William Fisher's constant-pressure pump governor, Marshalltown, Iowa, USA (1880) |
|---|---|
| Ownership | Owned by Monsanto from 1969; sold to Emerson in 1992 and combined with Rosemount as Fisher-Rosemount, later Emerson Process Management. Today a brand of Emerson. |
| Main site | Marshalltown, Iowa, USA |
| Product families | Sliding-stem and rotary control valves, spring-diaphragm and piston actuators, FIELDVUE digital valve controllers, pressure regulators, displacer and digital level controllers |
| Typical duty | Throttling control of liquids, gas and steam, high-pressure and severe service, instrument supply and gas pressure reduction |
Milestones
- 1880: William Fisher builds a constant-pressure pump governor in Marshalltown, Iowa.
- 1969: Monsanto acquires Fisher Controls.
- 1992: Emerson buys Fisher and combines it with Rosemount as Fisher-Rosemount, later Emerson Process Management.
Fisher valves, actuators and instruments
| Series | Type | Typical use |
|---|---|---|
| easy-e ES, ET, EZ | Sliding-stem globe and angle valves | Cage-guided globe valves: ES with unbalanced plug, ET with balanced trim for higher pressure drop; EZ unbalanced with a seat ring retainer for viscous or dirty fluids |
| GX | Compact globe valve with integral actuator | Standard chemical and process duty where a compact valve package is preferred |
| HPT, HPAT | High-pressure globe and angle valves | Pressure classes up to ASME CL2500, compressor recycle and high-pressure letdown |
| V150, V200, V300, V250 | Vee-Ball segmented ball and full-bore ball control valves | High-capacity control of liquids, gas and fibrous or slurry service |
| CV500 | Eccentric rotating plug valve | Erosive, coking and dirty service |
| 8560, 8580 | High-performance butterfly valves | Large-line throttling and on-off control |
| 657, 667, 1052, 1061, easy-Drive | Spring-diaphragm, piston and electric actuators | 657 and 667 for sliding-stem valves; 1052 and 1061 for rotary valves; easy-Drive where no air is available |
| FIELDVUE DVC6200, DVC2000, 3610J | Digital valve controllers and positioners | HART positioning with valve diagnostics; 3610J pneumatic positioner for rotary actuators |
| 627, 1098-EGR, 67C | Pressure regulators | Gas pressure reduction, pilot-operated regulation and instrument air supply |
| DLC3100, 2500 | Digital and pneumatic level controllers | Displacer level and interface on separators and scrubbers |
Where Fisher valves are used
Fisher control valves and regulators are standard equipment in oil and gas production, refineries, gas processing and LNG, petrochemicals, power plants and water systems. Typical loops are separator level and pressure, compressor anti-surge and recycle, fuel gas pressure reduction, feedwater and steam control, and chemical dosing. FIELDVUE controllers add diagnostics that help plan valve maintenance before a turnaround.
Ordering Fisher valves and spare parts: what we need
For spares, send the serial number from the valve nameplate together with the valve type, size, pressure class, trim and actuator type and size. Emerson keeps the build record behind the serial number, so plug, seat ring, cage, packing and diaphragm kits can be matched without guesswork. For a FIELDVUE or regulator, send the full model and type number and the mounting details. For a new valve add the process data: fluid, flow range, inlet and outlet pressure, temperature, leakage class, fail position, air supply and signal.
Facts checked against Emerson Fisher product information and published company histories, October 2026.
Browse Fisher products by category: Control Valves, Valve Actuator, Valve Positioner, Regulators, Level Transmitter.
FAQ
Questions about the Fisher CS800 Commercial/Industrial Pressure
Answers from our engineering team on installation, compatibility and integration.
01What outlet range does the CS800 cover?
The series covers 3.5 in. w.c. to 10 psig (9 mbar to 0.69 bar). The third digit of the type number selects low, medium or high pressure.
02What protection options are available?
Integral True-Monitor, an integral VSX8 slam-shut, and Secondary Seat protection, with or without a controlled bleed indicator.
03What is the maximum inlet pressure?
The emergency inlet rating is 175 psig / 12.1 bar. Operating inlet depends on orifice size and body material.
04Can the CS800 be used with hydrogen?
The bulletin states capability for up to 25% hydrogen blend by volume, and 100% hydrogen construction on request to the factory.
05What body materials are offered?
Gray cast iron, ductile iron and WCC steel, in NPT, Rp and DN 50 flanged forms.
Reviews
There are no reviews yet.