0191 5166636 enquiries@ht-uk.com

Watlow flanged immersion heaters are easy to install and maintain. Designed for heating liquids and gases in tanks and pressure vessels, flanged immersion heaters are ideal for applications requiring higher kilowatts.

Watlow flanged immersion heaters are made with WATROD or FIREBAR tubular elements brazed or welded to a flange. Stock flange heaters are equipped with a general purpose  terminal enclosure.

Flanged immersion heaters, with FIREBAR elements, also answer the need for liquid immersion applications requiring high kilowatts in small tanks. The FIREBAR element's unique flat surface geometry packs more power in a smaller bundle, with lower watt density, making it especially well-suited for petroleum-based liquid heating applications.


Material Maximum Operating Temperatures Maximum Watt Densities
°F °C W/in2 W/cm2
Alloy 800  1600 870 100 15.5
Stainless steel  1200 650 100 15.5
Steel  750 400 100 15.5
N/A  350 175 100 15.5
  • A conventional round tubular 10-inch ANSI flange can be replaced by a 6-inch ANSI FIREBAR flange
  • Watt densities to 100 W/in² (15.5 W/cm²)
  • Wattages to three megawatts
  • UL® and CSA component recognition to 600VAC
  • Passivated 316 stainless steel sheath temperatures to 1200°F (650°C)
  • 304 stainless steel sheath temperatures to 1200°F (650°C)
  • Steel sheath temperatures to 750°F (400°C)
  • FIREBAR flange heaters deliver more killowatts in smaller bundles
  • Alloy 800/840 sheath temperatures to 1600°F (870°C)


  • Deionized water
  • Demineralized water
  • Clean water
  • Potable water
  • Process water
  • Industrial water rinse tanks
  • Vapor degreasers
  • Hydraulic oil, crude, asphalt
  • Lubricating oils at API specified watt densities
  • Air and gas flow
  • Chemical baths
  • Process air equipment
  • Boiler equipment
  • Freeze protection of any fluid
  • Anti-freeze (glycol) solutions
  • Paraffin

Features & Benefits:

Features Benefits
ANSI and ANSI compatible 2, 2½, 3 thru 48 inch flanges
  • Provides appropriate heater size-to-application and fit
Element sheath and flange materials
  • Meets your application needs
Integral thermowells
  • Provides convenient temperature sensor insertion and replacement without draining the fluid being heated
Standard, general purpose terminal enclosure
  • Offers easy access to wiring
All units are inspected and/or tested
  • Ensures element-to-flange pressure seals do not leak
Drilled and tapped eyebolt holes or lift lugs for eye bolts on 10 inch and larger flange heaters
  • Facilitates lifting during installation
WATROD hairpins are repressed (recompacted)
  • Provides improved heater life, insulation resistance and heat transfer
Element support(s)
  • Provides proper element spacing to maximize heater performance and life