Series-F6-F7-Horizontal

Supported Applications

The Dwyer Series F6 and F7 Horizontal Float Level Switches provide point level indication for tanks and vessels. These reed-switch-based devices are designed to mount through tank walls or externally, detecting liquid levels via a float mechanism that actuates hermetically sealed contacts. Documented applications include monitoring water, oils, chemicals, corrosives, and liquids containing metal particles (bent stem models). Specific configurations support high-temperature/pressure environments, explosive atmospheres, sumps with slosh shields, stand pipes, and non-intrusive bottle-type external mounting.

Operating Conditions & Performance

The series covers a broad envelope of process conditions depending on the specific model construction. Operating temperatures range from 176°F (80°C) for polypropylene models up to 392°F (200°C) for F7-HSS stainless steel units; the externally mounted F7-EB supports -40°F to 300°F (-40°C to 148.9°C). Pressure ratings vary from 50 psig (3 bar) on vertical low-level models to 500 psig (34 bar) for the bottle-style external mount and up to 450 psig (31 bar) for specific internal stainless steel variants.

Minimum Specific Gravity (S.G.) requirements differ by model, ranging from 0.45 on Buna-N/PBT units to 0.90 for polyphenylene models. Electrical ratings include AC and DC loads such as 20 VA at 240 VAC or 30 VA at 220 VAC/DC, with specific current limits (e.g., 0.1A @ 120V). The F7-HSS model is rated explosion-proof for Class I, Groups A, B, C, D; Class II, Groups E, F, G; and Class III.

Model-Specific Performance Limits

• F6-HPS-11 / F6-HPS-31: 176°F (80°C), 116 psig (8 bar).
• F6-MHS / F6-MHS2: Up to 257°F (125°C) and pressures of 218–363 psig (15–25 bar).
• F7-HSS: 392°F (200°C), 300 psig (20.7 bar); explosion-proof rated.
• F7-EB: -40°F to 300°F (-40°C to 148.9°C), 500 psig Max @ 70°F.

Configuration Options

The series offers configurable wetted materials, mounting styles, and electrical outputs tailored to media compatibility and installation constraints. Wetted material options include Polypropylene, Polysulfone, Buna-N, PBT, 304 SS, 316 SS (CYC), Brass, and Epoxy coatings.

Mounting & Process Connections

• Horizontal Mount: Models F6-HPS-11/31 feature M16 x 2 or 1/2" NPT connections for through-wall installation.
• Bent Stem (F7-SS6): Designed for liquids with metal particles, utilizing a 3/8"-24 UNF-2A connection.
• External Bottle Mount (F7-EB): Features 3/4" NPT inlet and outlet ports for non-intrusive installation on the outside of tanks.
• Vertical/Low Level: F7-LL uses a 1/8" NPT male connection to detect levels as low as 5/8".

Electrical & Output Options

• Contact Type: SPST, Normally Open (N.O.) or Normally Closed (N.C.). The F7-EB allows selection of N.O. or N.C. by inverting the float on the stem.
• Cable Lengths: Standard lead wires range from 11.8" to 24", with a specialized 25' cable option for sump applications (F7-WBB).
• Wire Gauge: Available in No. 18 AWG, 20 AWG, or 22 AWG depending on the model.

Hazardous Location & Approvals

• F7-HSS is rated explosion-proof for Class I, Groups A, B, C, D; Class II, Groups E, F, G; and Class III.
• The F7-EB carries U.L. Recognized File No. E45168 and CSA Report LR 30200 approvals.

Key Product Differences

Differences within the series are defined by material construction, mounting orientation, and specific service requirements:

• F6 Series (Horizontal): Includes F6-HPS models for general water/oil/chemical use in polypropylene/polyphenylene, and F6-MHS/MHS2 stainless steel variants for corrosive media with higher pressure ratings.
• F7 Horizontal & Specialty: The F7-HSS provides the highest temperature (392°F) and explosion-proof rating. The F7-SS6/SS6B models feature a bent stem design specifically for liquids containing metal particles to prevent contact damage.
• External Mounting: The F7-EB is distinct as an externally mounted bottle-style switch, eliminating the need for internal tank penetration and supporting higher pressures (500 psig).
• Sump & Stand Pipe: The F7-WBB variant includes a 25' cable with a slosh shield for sumps and stand pipes.