The Dwyer V6EPB-B-S-LFE is a Series V6 Flotect mini-size flow switch with a brass upper and lower body, a SPDT snap switch, and an integral 1/2 in BSPT tee with an adjustable valve. A free-swinging vane in the flow stream carries a magnet that trips the snap switch through the solid metal switch body, so there are no bellows, springs or seals in the media path. It monitors air, water and other gases and liquids compatible with the wetted materials to 1450 psi (100 bar) and -4 to 220°F (-20 to 105°C) in a weatherproof housing designed to meet NEMA 4 and rated explosion-proof for hazardous locations. The set point is field adjustable: loosen the four socket head cap screws on the bottom and rotate the adjustment valve 90 degrees between O (open) and C (closed).
Best for
- Protecting pumps, motors and other equipment against low or no flow
- Sequencing pump operation and auto-starting auxiliary pumps or engines
- Shutting down liquid-cooled engines and machines when coolant flow stops
- Proving combustion air flow through a heating coil before a burner fires
- Controlling dampers according to flow
- Signalling an alarm when an emergency shower or eyewash station is in use
Magnetic vane actuation
A free-swinging vane attracts a magnet inside the solid metal switch body, actuating the snap switch through a simple lever arm. No bellows, springs or seals sit in the media path.
Weatherproof, explosion-proof enclosure
Weatherproof housing designed to meet NEMA 4 and rated explosion-proof, so the switch can be installed in hazardous locations without a separate purged or pressurised enclosure. See Technical Specifications for the enclosure listing and hazardous location groups.
Field-adjustable low flow set point
An integral tee and adjustable valve set actuation anywhere from 0.04 to 0.75 GPM on water or 0.18 to 2.70 SCFM on air in 1/2 in pipe.
Leak-proof bar-stock body
The switch body is machined from bar stock, and the vane assembly is magnetically coupled rather than mechanically sealed.
Serviceable without draining the line
The electrical assembly can be replaced without removing the unit from the installation, so the process does not have to be shut down.
Rated to 1450 psi
Low flow models carry a 1450 psi (100 bar) pressure limit with a Buna-N O-ring standard; fluoroelastomer is available under the -VIT option.
| Service | Gases or liquids compatible with the wetted materials |
| Wetted Materials | Lower body: Brass; tee: Brass; magnet: ceramic; O-ring: Buna-N standard (fluoroelastomer optional); other: 301, 302 SS |
| Upper Body | Brass |
| Switch Type | SPDT snap switch |
| Electrical Rating | 5 A @ 125/250 VAC |
| Electrical Connections | 18 AWG leads, 18 in [460 mm] long. Black = common, blue = normally open, red = normally closed |
| Process Connection | 1/2 in BSPT inlet and outlet (integral tee) |
| Conduit Connection | M25 x 1.5 (BSPT option) |
| Pressure Limit | 1450 psi (100 bar), low flow models |
| Temperature Limit | -4 to 220°F (-20 to 105°C), standard |
| Enclosure Rating | Weatherproof, designed to meet NEMA 4, and explosion-proof. The Series V6 enclosure is listed with UL and CSA for Class I, Groups B, C and D; Class II, Groups E, F and G |
| Set Point Adjustment | Field adjustable within the range shown |
| Mounting Orientation | Any position. Chart flow rates are based on horizontal pipe runs and are nominal values |
| Dimensions | Overall height 4-1/2 in [114.3 mm]; inlet to outlet 3-5/8 in [92.07 mm]; switch body 1-1/8 in square [28.57 mm] |
| Weight | 2 to 6 lb (0.9 to 2.7 kg) depending on construction |
| Option-Only Certifications | ATEX, IECEx and KC certification require the -AT, -IEC or -KC option suffix and are not included on this model |
| Media (1/2 in pipe) | Actuate | Deactuate |
|---|---|---|
| GPM - water | .04-0.75 | .03-0.60 |
| LPM - water | .15-2.84 | .11-2.27 |
| SCFM - air | .18-2.70 | .15-2.0 |
| LPS - air | .09-1.3 | .07-.95 |
Pressure drop (head loss) is a function of both set point and flow rate. At the listed actuation flow rate, pressure drop is typically 5-10 psid (0.34-0.69 bar).
What media can the V6EPB-B-S-LFE monitor?
Air, water and any other gas or liquid compatible with the wetted materials: lower body: brass; tee: brass; magnet: ceramic; o-ring: buna-n standard (fluoroelastomer optional); other: 301, 302 ss.
What is the adjustable flow range?
In 1/2 in pipe, actuation is adjustable from 0.04 to 0.75 GPM on water (0.15 to 2.84 LPM) or 0.18 to 2.70 SCFM on air. To adjust, loosen the four socket head cap screws on the bottom and rotate the adjustment valve 90 degrees between O (open) and C (closed).
What is the pressure drop across the switch?
Pressure drop depends on both set point and flow rate. At the listed actuation flow rate it is typically 5 to 10 psid (0.34 to 0.69 bar).
How is the SPDT wired?
The V6EPB-B-S-LFE carries a SPDT snap switch with 18 AWG leads, 18 in [460 mm] long, rated 5 A @ 125/250 VAC. Black is common, blue is normally open and red is normally closed. Normally open contacts close and normally closed contacts open as flow rises to the actuation point.
Is this model ATEX or IECEx certified?
No. The V6EPB-B-S-LFE is the standard explosion-proof construction. ATEX compliance requires the -AT option, IECEx requires -IEC and Korean certification requires -KC, each supplied with a junction box. Units without the AT suffix are not Directive 2014/34/EU compliant and are not intended for use in potentially hazardous atmospheres in the EU.
Can it be mounted vertically?
Yes. The switch can be installed in any position, but the actuation and deactuation flow rates in the charts are based on horizontal pipe runs and are nominal values. Install with the body arrow pointing in the direction of flow.
Specifications from Dwyer datasheet DS-V6 Rev. 4 (1/21) and Dwyer Bulletin E-22, FR# 440805-00 Rev. 18 (8/21). Verified 2026-08-06.
Manufacturer Warranty. Warranty terms are product-specific. Where no different product-specific warranty is supplied with the product, DwyerOmega's standard warranty covers defects in materials and workmanship under normal use for one year from delivery. See the manufacturer's current warranty policy for the governing terms.
Coverage does not extend to damage from mishandling, improper installation, operation outside published ratings, or unauthorized modification. Repairs are to be performed by the manufacturer; units needing repair should be returned to the factory prepaid. ZOT Supply is a Dwyer distributor. Contact us for warranty support and return authorization.
- Type:
- Flow Switch
- Switch Output:
- SPDT
- Product Series:
- V6 Flotect
- Body Material:
- Brass
- Tee Material:
- Brass (Integral)
- Set Point Adjustment:
- Field Adjustable
- Enclosure Rating:
- Weatherproof and Explosion-Proof
- Connection Type:
- BSPT
- Connection Size:
- 1/2 in
- Pressure Limit:
- 1450 psi
