Screw Plug Heaters

Screw Plug heaters from WATTCO™ consist of hairpin tubular elements that are brazed or welded into a machined pipe thread fitting, (normally an NPT fitting for North American standards) which are then screwed directly through a threaded coupling in the tank wall or vessel, or installed in pipe. Screw plug heaters are an easy way to heat up solutions in smaller containers that also require controls. Mechanical thermostats or Digital control panels can be used with these immersion heaters to help reach target temperatures with great accuracy meeting your project objectives. Additional thermowells can be installed for high limit temperature probes to help protect your liquid and processes.

WATTCO™ Screw Plug Heater in a TankScrew Plug industrial heaters from WATTCO™ are used for heating gases and liquids in tanks or vessels. These submersible heating elements have been designed so that heat transfer will occur at a rapid rate, enabling quick liquid heat up times. Typically they are implemented in the food and beverage industry, laboratory clinics, applications involving hydraulic oils and lubricants as well as more sophisticated uses such as heating up flammable liquids or gases which require explosion proof housing.

Get a quote on a screw plug heater solution today or feel free to contact us today for any additional information.


At Wattco, we have a dedicated team of experts ready to provide you with the answers and assistance you need. Whether you're a seasoned professional looking for technical specifications or in maintenance inquiring about our products, our team of knowledgeable professionals is here to help. 

  • Options
  • Sheath Material

    Copper, Steel, Incoloy, Inconel, Stainless steel and Titanium available

  • Terminal Boxes

    NEMA 1, 4, 4x, 7 terminal boxes are available

  • Controls

    Mechanical Thermostats, Thermocouples and RTD sensors

  • Screw plug NPT Fittings

    1 inch, 1 1/4 inch, 1 1/2 inch, 2 inch, 2 1/2 inch, 3 inch and 4 inch available

  • Screw Plug Material

    Stainless Steel, Brass, Steel or Titanium Screw plugs available

Screw Plug Heater 1 inch NEMA 1 1el
Screw Plug Heater 1 inch NEMA 4 1el
Screw Plug Heater 2 inch NEMA 1 2el
Screw Plug Heater 2 inch NEMA 1 2el pic3
Screw Plug Heater 2 inch NEMA 1 3el
Screw Plug Heater 2 inch NEMA 1 3el no button
Screw Plug Heater 2 inch NEMA 4 2el
Screw Plug Heater 2 inch NEMA 4 3el
Screw Plug Heater 2 inch NEMA 7 2el
Screw Plug Heater 2 inch NEMA 7 3el

Sheath materials:

Stainless steel


Applications Sheath Material Screw Plug Material
Clean water, Freeze protection, hot water storage, Boiler and water heaters, cooling towers, Solutions not corrosive to copper Copper Steel
Hot water, steam boilers, mildly corrosive solutions (in rinse tanks, spray washers) Incoloy Steel
Oils, Gases, Mildly corrosive liquids, stagnant or heavy oils, high temperature, low flow gas heating Steel Steel
Process water, soap and detergent solutions, Soluble cutting oils, demineralized or deionized water Stainless Steel Stainless Steel
Mildly corrosive solutions Stainless Steel Stainless Steel
Severe corrosive solutions, demineralized water Incoloy Stainless Steel
Light Oil, Medium Oil Steel Steel
Food Equipment, Food Equipment with cut out Incoloy Stainless Steel



NPT screw plugs: 1”, 1 ¼”, 1 ½”, 2”, 2 ½”, 3” and 4’’ Energy efficient
Stainless Steel, Brass or Steel Screw plugs Easy to regulate
0.260”, 0.315”, 0.375”, 0.430” and 0.475” diameters available Easy to install or remove
Sheath materials: Copper ,Steel ,Incoloy®, Inconel®, Stainless steel, Titanium Easy to maintain
Available explosion and/or moisture resistant terminal enclosures upon request. Custom-designed

  • Compact
  • Designed and built for safety
CSA, CSA US and UL approved

  • NEMA 1, 4, 4x, 7 terminal boxes are available
CSA™ and UL approved