Watlow Screw Plug Heater

  • Wattages up to 38 kW
  • Heat immersion for all oil or heat transfer fluids
  • Variety of sizes and shapes
  • UL and CSA component approval


Watlow Screw Plug Immersion Heaters are useful for direct heating of liquids. This includes all types of oil and heat transfer solutions. Also the Watlow Screw Plug Heater is available in a variety of sizes and two different shapes. The WATROD round and FIREBAR flat tubular elements.

The heating elements are welded or brazed into the screw plug. Specifically based on the element sheath and plug material compatibility. All heating elements are hairpin bent and come standard with general purpose terminal enclosure. In addition, moisture resistant, explosion resistant and explosion/moisture resistant enclosures are available to meet specific application needs.

Furthermore, optional thermostats provide convenient process temperature regulation to the screw plug immersion heater.

Watlow Screw Plug Heater

  • Variety of element sheath and screw plug materials to meet the needs of many application needs.
  • Integral thermowells which provide convenient temperature sensor insertion and replacement without draining fluid.
  • Terminal enclosures which provide the ability to be rotated to simplify connection with existing conduits.
  • 2-1/2 in. (64 mm) NPT screw plug assemblies feature element support(s). This ensures proper spacing for maximizing heater performance and life

Typical Applications for Screw Plug Heater

The Watlow immersion screw plug heaters can be used in a wide range of applications. Screw Plug heaters that are used in water are applicable in deionized, demineralized, clean, potable, and process solutions.
Additionally, other common applications are industrial water rinse tanks, vapor degreasers, hydraulic oil, crude, asphalt, lubricating oils at API specified watt densities, air and gas flow, caustic solutions, chemical baths, anti-freeze (glycol) solutions, and paraffin.

We provide engineering and product support for your application.

Technical Documentation

Download PDF files:

Watlow Screw Plug Heater Specifications

Watlow Screw Plug Heater Catalog