Hardwired Instrumentation Solutions

OleumTech Hardwired Sensors and Switches


Single or Dual Magnetic Float Actuation Liquid Level Detection Solution



  • Provides high liquid level detection using
    reliable magnetic reed switch design
  • Does not require power
  • Single or dual actuation option for high/high-high
  • 12” to 108” (30.5 to 274.3 cm) stem length option
  • Switch Material: 316 Stainless Steel
  • Process temperature: -40 to 120 °C (-40 to 248 °F)
  • Max pressure: 497.8 PSI / 35 kg/cm2 / 34.3 BAR
  • Supports Normally Open or Normally Closed output, user-configurable
  • Supports inductive and capacitive loads
  • NEMA 4X, IP66
  • Zone 0 / Explosion-proof / Flameproof
  • Tank Level Switch also available for side mount applications

Reed Switch Reliability / Low Maintenance

The Float Type Level Switch by OleumTech is part of the H Series line of high quality instruments delivering unrivaled performance, reliability, and accuracy in the most demanding environments, including hazardous locations.

The float-based level switch is designed to be mounted on the top of a liquid storage tank and is used for detecting critical overfill conditions for high level alarm, monitoring, and control applications. The HLTFD provides support for Normally Open (NO) or Normally Closed (NC) output type and supports inductive and capacitive loads.

Explosion-proof Tank Level Switch / Durable 316SS

The H Series HLTFD Float Type Level Switch is certified for use in Zone 0 hazardous locations and is Explosion-proof/Flameproof.

The HLTFD is a simple apparatus and does not require power to operate. The level switch can be ordered with a single or dual actuation switching option along with customizable set points. The stem length is available from 1 ft to 9 ft lengths in 1” increments.


Device Functionality∙ Liquid Level Detection Switch using Float-based Reed Switch Technology
Interface∙ Relay
Dimensions (Head)∙ 4.45" (W) x 4.25" (H) x 4.45" (D) / 113 mm (W) x 108 mm (H) x 113 mm (D)
Stem Length∙ 12" to 108" (30.5 cm to 274.3 cm)
Float Dimensions∙ 1.6 (W) x 1.5" (H) x 0.43" (ID) / 41 mm (W) x 38 mm (H) x 11 mm (ID)
Specific Gravity (SG)∙ >0.7
Package Dimensions∙ Dependent on Switch Length (Ask Sales for Details)
Package Weight∙ Dependent on Switch Length (Ask Sales for Details)
Ports∙ Two 1/2" NPT (One Plug Provided)
Connection Fitting (Standard)∙ 2" NPT, see datasheet for all available connection sizes
Connection Fitting Options∙ NPT, BSP, PF, 150 lbs, 300 lbs
Enclosure Casing Material∙ Type 4X Aluminum; IP66
Switch Material∙ 316 Stainless Steel
Operating Pressure∙ 497.8 PSI / 35 kg/cm2 (34.3 BAR)
Signal Output∙ SPST Reed Switch, 240 Vac / 200 Vdc, 50 W, 0.5 A
Output Modes∙ Normally Open or Normally Closed
Safety∙ Explosion-Proof/Flameproof for Use in Hazardous Environments
∙ IECEx TUR 19.0036
∙ Ex db IIB T4 Gb, Ex tb IIIC T135 °C Db
Operating Conditions∙ Process Temperature: -40 to 120 °C (-40 to 248 °F)
∙ Ambient Temperature: -40 to 70 °C (-40 to 158 °F)
∙ Humidity: 0 to 99 %, Non-Condensing
Warranty∙ 2-Year Parts and Labor
Model Numbers Series∙ HLTFD