Series-V4

Supported Applications

The Dwyer Series V4 Flotect® is a vane-operated flow switch designed to automatically protect equipment and pipeline systems against damage from reduction or loss of flow. The series operates using a magnetically actuated switching design where a free-swinging vane attracts a magnet within the solid metal switch body, actuating a snap switch via a lever arm without bellows, springs, or seals that can fail.

Documented applications include:

• Protecting pumps and motors against low or no flow conditions
• Controlling sequential pump operations
• Shutting down burners or engines when coolant or air flow is interrupted
• Pipeline monitoring in processing plants using pipes 1-1/2" and up

The switch accommodates gases or liquids compatible with the wetted materials.

Operating Conditions & Performance

The Series V4 is rated for weatherproof and explosion-proof environments. Enclosure listings include UL and CSA (Class I, Groups C and D; Class II, Groups E, F, and G), ATEX (II 2 G Ex db IIB T6 Gb -20°C≤Tamb≤73°C), IECEx (Ex db IIB T6 Gb Zone 1), and FM approval.

Performance limits vary by construction:

• Ambient Temperature: Standard models operate from -4 to 275°F (-20 to 135°C). The MT high temperature option extends this range to -4 to 400°F (-20 to 205°C) but is not UL, CSA, ATEX, or IECEx listed. ATEX and IECEx units are limited to -4 to 163°F (-20 to 73°C).
• Process Temperature: All options support -4 to 163°F (-20 to 73°C). For ATEX/IECEx, process temperatures up to 271°F are permitted provided the enclosure and switch body temperature do not exceed 163°F.
• Pressure Rating: Brass bodies support 1000 psig (69 bar); 316 SS bodies support 2000 psig (138 bar). An optional 5000 psig (345 bar) rating is available with a 316 SS body and SPDT switch only.
• Flow Ranges: Actuation/deactuation rates vary by pipe size (1.5" to 20") and vane layer configuration, covering ranges from 7-3 GPM up to 2400-1200 GPM for cold water.

Electrical Ratings

• UL, FM, ATEX, IECEx models: 10 A @ 125/250 VAC; CSA models: 5 A @ 125/250 VAC.
• DC Ratings (Standard): 5 A resistive, 3 A inductive @ 30 VDC.
• MV Option: 1 A @ 125 VAC; 1 A resistive, 5 A inductive @ 30 VDC.

Configuration Options

The Series V4 offers extensive configuration options for construction materials, outputs, and special service requirements. The series supports the following capabilities:

Housing & Wetted Materials

• Body Material: SAE 72 Brass or 316 Stainless Steel.
• Vane Material: Standard 316 SS; other materials available upon consultation (e.g., PVC, hastelloy, nickel, monel, titanium).
• Magnet Keeper: 430 SS standard or optional 316 SS.

Outputs & Switching Options

• Standard Output: SPDT snap switch.
• Optional Outputs: DPDT snap switch (-D), Gold plated contacts for dry circuits (-MV).
• Time Delay Relays: Increasing flow time delay relay (-TRI) or decreasing flow time delay relay (-TRD). These provide 2 SPDT contacts with field-adjustable delays from 0-1 to 0-31 minutes.

Hazardous Location & Special Service

• Approvals: ATEX compliant construction (-AT) and IECEx certified construction (-IEC).
• High Temperature: MT option rated to 400°F (204°C), not listed for hazardous locations.
• NACE Heat Treated Body
• Epoxy Coated Housing
• No Electrical Housing (-NH): Available but has no approvals.

Mechanical & Installation Options

• Process Connections: 1-1/2" male NPT standard or 1-1/2" male BSPT (-BSPT).
• Conduit Connection: 3/4" female NPT standard or M25 with -BSPT option.
• Mounting Orientation: Within 5° of vertical for proper operation. Vertical up flow applications available via the (-V) option.

Key Product Differences

The Series V4 distinguishes between standard and hazardous location configurations through specific model codes and physical features:

• Housing Style: Standard units feature an explosion-proof housing with a 3/4" female NPT conduit connection. ATEX/IECEx variants include a cover lock, external ground, and terminal block connections instead of pre-wired leads.
• Vane Configuration: The universal vane design allows set point adjustment via five different layer combinations to match specific flow rates for pipe sizes ranging from 1.5" to 20".
• Body Construction: Short style brass bodies (-2) and 316 SS bodies with a standard 430 SS magnet keeper are available, alongside options for full swing vanes or custom vane materials.