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Brand: Honeywell
Honeywell SmartLine STF800 Flange Mount Level Transmitter
Description
STF800 SmartLine flange-mounted level transmitter
The Honeywell SmartLine STF800 is a flange-mounted pressure transmitter used mainly for liquid level in tanks and vessels. It bolts straight to a nozzle on the vessel, so the diaphragm sits at the process and there are no impulse lines to plug, freeze or leak. Honeywell offers flush, extended-diaphragm and pseudo-flange configurations, with a piezoresistive silicon sensor, automatic static pressure and temperature compensation, and the same electronics family as the other ST 800 SmartLine models. Seven Star LLC supplies the STF800 in Oman and the GCC as an independent supplier in Muscat.
Level on viscous, corrosive, crystallising or dirty liquids is where the STF800 earns its place: the wetted flange face replaces a long impulse line and keeps the measurement close to the process.
STF800 models and ranges
| Model | Range (URL / LRL) | Min span | Max turndown | Stability (% URL per year, 15 years) | Reference accuracy, % of span (std / opt) |
|---|---|---|---|---|---|
| STF828 | 400 inH2O / −400 inH2O (1,000 mbar) | 4 inH2O (10 mbar) | 100:1 | 0.01 | 0.0375 / 0.025 |
| STF82F | 400 inH2O / −400 inH2O (1,000 mbar) | 4 inH2O (10 mbar) | 100:1 | 0.01 | 0.0375 / 0.025 |
| STF832 | 100 psi / −100 psi (7 bar) | 1 psi (0.07 bar) | 100:1 | 0.025 | 0.0375 / 0.0325 |
| STF83F | 100 psi / −100 psi (7 bar) | 1 psi (0.07 bar) | 100:1 | 0.025 | 0.0375 / 0.0325 |
The STF828 and STF832 have a separate mounting flange available in carbon steel, 304 or 316 stainless steel, while the STF82F and STF83F use a 316L stainless steel mounting flange that is itself wetted by the process.
STF800 technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Honeywell / STF800 (SmartLine flange-mounted level; model code STF828, STF82F, STF832 or STF83F) |
| Rangeability | Up to 100:1 |
| Response time | As fast as 90 ms (DE and HART); 150 ms for FOUNDATION Fieldbus (host dependent) |
| Output / protocol | 4 to 20 mA with HART 7 or Honeywell DE; FOUNDATION Fieldbus |
| Supply voltage at terminals | HART 10.8 to 42.4 VDC; DE 15 to 49.3 VDC; FOUNDATION Fieldbus 9.0 to 32.0 VDC |
| Ambient temperature, rated | −40 to 85 °C (−40 to 185 °F) |
| Meter body temperature, rated | −40 to 110 °C (operative limit 125 °C) |
| Process interface temperature (STF828, STF832) | Rated −40 to 110 °C; operative limit up to 175 °C |
| Flanges (STF828, STF832) | 2, 3 or 4 in ANSI Class 150 or 300; DN50-PN40, DN80-PN40 or DN100-PN40 DIN |
| Flanges (STF82F, STF83F) | 2 or 3 in ANSI Class 150, 316L SS |
| Extended diaphragm length | 2, 4 or 6 in (50, 101 or 152 mm) |
| Diaphragm materials | 316L SS, Hastelloy C-276 or Monel 400 (Monel and some Hastelloy options for flush or pseudo flange designs) |
| Fill fluid | Silicone 200, CTFE, NEOBEE M-20 or Silicone 704 |
| Housing | Polyester powder-coated low-copper aluminium; Type 4X / IP66 / IP67; stainless steel optional |
| Weight | STF82F and STF83F: 14 to 19 lb (6.4 to 8.7 kg); STF828 and STF832: 18 to 32 lb (8.2 to 14.5 kg), aluminium housing |
| Approvals and certificates listed | FM, CSA, ATEX, IECEx hazardous-area approvals; marine certificates ABS, BV, DNV, KR, LR; IEC 61508 SIL 2/3 |
How the STF800 measures level
The wetted diaphragm on the flange face senses the hydrostatic head of the liquid, and the fill fluid carries that pressure to the sensor in the meter body. A reference head on the low side is connected to the vessel vapor space for closed tanks, or left vented for open tanks. The transmitter then converts the measured differential into a level signal. Because the sensor also measures static pressure and temperature, the electronics can correct for both.
The extended diaphragm design pushes the sensing face 2, 4 or 6 inches into the nozzle so that it clears a thick insulation layer or a build-up zone. A pseudo-flange design is also listed in the model selection guide. Choose the design from the nozzle depth, the likely scaling and the cleaning method.
STF800 pressure ratings and limits
Pressure rating depends on flange class and material. For the STF828 and STF832 at ambient temperatures of −29 to 38 °C the datasheet gives 285 psi (19.6 bar) for a Class 150 carbon steel flange and 740 psi (51 bar) for Class 300 carbon steel, while the 316 stainless steel equivalents are 275 psi and 720 psi. A DN PN40 carbon steel flange is rated 580 psi (40 bar). These figures fall as the meter body and process interface temperatures rise, so use the full table in the datasheet when the process is hot. For the STF82F and STF83F, the 316L stainless steel flange is rated 230 psi (15.9 bar) at ambient. Overpressure is 1.5 x MAWP.
STF800 selection and ordering checklist
- Model: STF828 or STF832 for a separate flange of your choice, STF82F or STF83F for the 316L flange version.
- Span: calculate the level span in inH2O or psi from the liquid density and the tap-to-tap height, and stay within 100:1.
- Diaphragm design: flush, extended 2, 4 or 6 inches, or pseudo flange.
- Flange: size, ANSI class or DIN PN40, and flange material that matches the nozzle on the vessel.
- Wetted material: 316L stainless steel, Hastelloy C-276 or Monel 400 depending on the medium.
- Fill fluid: choose for process temperature, because Silicone 704 starts at 0 °C and NEOBEE M-20 at −15 °C.
- Protocol, display and approval: HART, DE or Fieldbus, with a hazardous-area approval for your plant.
STF800 installation, commissioning and maintenance
Check the nozzle face, gasket and bolt pattern before mounting, because the flange gasket is part of the process seal. Fit the transmitter so the housing is easy to reach, and connect the reference side so that it is dry for a closed vessel. Set the lower and upper range values from the true product levels and check the reading when the tank is at a known level. Do not scrape or prod the diaphragm when cleaning, since a damaged face means a new meter body.
Honeywell lists four-year calibration verification as typical. The electronics, display and lightning protection modules can be replaced without changing the meter body, which helps when a spare module is held on site.
Typical applications of the STF800 in Oman and the GCC
In the Gulf the STF800 is used for level in crude and condensate separators, slop and process water tanks, chemical dosing and storage tanks, boiler feedwater and deaerator vessels, and sumps where an impulse line would foul. Where tanks sit in strong sun, shade the housing where practical and use sealed cable entries to keep dust and humidity out of the housing.
Related SmartLine models
The STF800 sits beside the STD800 differential pressure transmitter, which is selected when impulse lines or manifolds are acceptable, and the STA800 absolute pressure model used for vacuum and absolute reference. All three share electronics, displays and configuration tools.
STF800 information to send with an RFQ
- Model (STF828, STF82F, STF832 or STF83F) and level span
- Tank type, nozzle size and flange class or DIN rating
- Process fluid, density, pressure and temperature
- Diaphragm design and extension length
- Wetted material and fill fluid
- Protocol, display and approval; quantity and delivery location
Documents and quotation
A Honeywell STF800 technical specification (34-ST-03-87) is attached on this page, with the flange pressure ratings and the model selection tables.
Send the STF800 model or the vessel and nozzle details, and we will prepare a quotation for delivery in Oman and the GCC.
Other Models in the Smartline St800 Range
Seven Star LLC supplies models from the Smartline St800 range in Oman and the GCC. Compare the related models below and request a quote for the one that matches your application.
| Model | Category | |
|---|---|---|
| Honeywell SmartLine STA800 Absolute Pressure Transmitter | Pressure Instrumentation | View details |
| Honeywell SmartLine STD800 Differential Pressure Transmitter | Pressure Instrumentation | View details |
| Honeywell SmartLine STF800 Flange Mount Level Transmitter | Pressure Instrumentation | You are viewing this model |
Datasheets & Documents
- Datasheet Honeywell STF800 Specification Download
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About brand
Honeywell is the American industrial technology group whose products on this site cover gas and flame detection, pressure transmitters, flow measurement, gas metering, fire alarm systems and helicopter rotor balancing equipment. Its roots go back to a thermostat business in Minneapolis in 1885 and to Mark Honeywell's heating company, which merged with it in 1927. Several brands we list have joined Honeywell over the years: Gent fire systems of Leicester (part of Honeywell since 2005), Chadwick-Helmuth (a Honeywell business unit from 2002) and Elster gas metering (acquired around the end of 2015).
Seven Star LLC is an independent supplier in Muscat. We list Honeywell gas detectors and sensors, transmitters, Elster gas meters and flow computers, Gent fire alarm equipment and Chadwick-Helmuth balancers, and supply them and their spares in Oman and the GCC by part number.
Honeywell company profile
| Origins | 1885, Minneapolis (Butz thermostat business); merged with Mark Honeywell's company in 1927 |
|---|---|
| Brands in our range | Honeywell Analytics gas detection, SmartLine transmitters, Elster gas metering, Gent fire detection, Chadwick-Helmuth rotor track and balance |
| Gent | Founded in Leicester, UK, around 1872 by John Thomas Gent; part of Honeywell since 2005 |
| Elster | Gas, water and electricity metering; bought by Honeywell from Melrose, deal completed around the end of 2015 |
Milestones
- 1885: The Butz thermostat business starts in Minneapolis.
- 1927: It merges with Mark Honeywell's company.
- 2005: Gent fire detection (Leicester, UK) becomes part of Honeywell.
- 2015: Honeywell completes the purchase of Elster from Melrose around the end of the year.
Honeywell products we list
| Family | Models | Typical use |
|---|---|---|
| Fixed gas detectors | Searchline Excel, Searchline Excel Plus, 02104-N-XSSA, Sensepoint XCD RTD, Sensepoint XCD IR, XCD H2, Sensepoint XCL, Sensepoint XRL, OmniPoint, RAEGuard 2 PID | Flammable, toxic and VOC gas detection in process areas |
| Sensors, flame detection and control | SR-W-MP75C LEL sensor, SR-X2V O2 sensor, FS24X Plus flame detector, R4343E flame switch, System 57 card, 5704FS panel | Replacement sensors, fire detection and gas detection control panels |
| Transmitters and flow | SmartLine STG700, STG800, STR82D remote seal, VersaFlow Coriolis | Process pressure and mass flow measurement |
| Elster gas metering | Q.Sonic plus, TRZ2, Quantometer, RABO, IRM-3 DUO, EK280, EC 350, enCore FC1, enCore ZM1, gas-net F1, gas-net D2, GasLab Q2, USM display | Gas meters, volume correction and fiscal flow computing |
| Gent fire alarm systems | Vigilon Plus, Vigilon Compact Plus, Nano, Xenex, S-Quad detector, S-Cubed, ALD302 base, S4-34420 interfaces, loop card, repeat panel, mimic panel, XENS-850 call point, 74430 bell | Addressable and conventional fire alarm systems in buildings and plants |
| Chadwick-Helmuth rotor track and balance | 8500C, 8500C Plus, Vibrex 2000, Model 11, photocell system, printer, bracket, protractor | Helicopter rotor track and balance and propeller balancing |
Gas detection uses two basic approaches. Point detectors such as the Sensepoint XCD measure the gas at one location, with a catalytic or infrared sensor for flammable gas and an electrochemical cell for toxic gas such as H2S. Open path detectors such as the Searchline Excel send an infrared beam across an area up to a few hundred metres long and detect a gas cloud anywhere along it. Infrared sensors cannot be poisoned the way catalytic beads can, which matters on sites with silicones or H2S.
Where Honeywell products are used
In Oman and the GCC, Honeywell gas detectors protect wellheads, gas plants, refineries and tank farms. Elster meters and flow computers measure gas at city gate stations and in industry. Gent systems are installed in commercial buildings, hospitals and hotels, and Chadwick-Helmuth balancers are used by helicopter operators.
Ordering Honeywell products: what we need
Send the part number from the label (for example 02104-N-XSSA or SPXCDASMTXF). For gas detectors, add the gas, range, output and certification. For gas meters, add size (DN), flow range and pressure rating. For Gent equipment, add the panel type and loop protocol.
Facts checked against Honeywell press releases and SEC filings, and published histories of Gent and Chadwick-Helmuth, October 2026.
Browse Honeywell products by category: Fire & Gas Detector, Vibration, Flowmeters, Pressure Instrumentation, Temperature Instrumentation.
FAQ
Questions about the Honeywell SmartLine STF800 Flange Mount Level
Answers from our engineering team on installation, compatibility and integration.
01What does the STF800 measure?
It is a flange-mounted transmitter for liquid level in tanks and vessels, with the diaphragm at the nozzle so that no impulse lines are needed. Ranges are 400 inH2O (1,000 mbar) or 100 psi (7 bar).
02Which diaphragm designs can the STF800 have?
The datasheet lists flush, extended-diaphragm (2, 4 or 6 inch) and pseudo-flange designs. Availability depends on model and wetted material.
03What flange sizes does the STF800 accept?
The STF828 and STF832 take 2, 3 or 4 inch ANSI Class 150 or 300 and DN50, DN80 or DN100 PN40 flanges. The STF82F and STF83F use a 2 or 3 inch Class 150 316L flange.
04How accurate is the STF800?
Reference accuracy is 0.0375 % of span standard, with 0.025 % optional for STF828 and STF82F and 0.0325 % for STF832 and STF83F. Rangeability is up to 100:1.
05Does the STF800 have marine or SIL certification?
The ST 800 family lists ABS, BV, DNV, KR and LR marine certificates and IEC 61508 SIL 2 or SIL 3. These are options, so state them when ordering.
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