FIREROD Immersion Cartridge Heaters

Zesta FIREROD Immersion Cartridge Heaters
Zesta FIREROD Immersion Cartridge Heaters
FIREROD® cartridge immersion heaters are ideal for replacing large screw-plug immersion heaters. The heater packages up to 300 W/in2 (46.5 W/cm2) in a compact unit, enabling a versatile heating system design.

These heaters include a brass or stainless steel 3⁄4 inch National Pipe Thread Taper (NPT) double threaded fitting, which allows conduit boxes to be added. Also, FIREROD immersion heaters are sealed at the lead end with silicone rubber potting.

Solid copper leads with silicone rubber sleeves are provided for heavy-duty wiring. These units are recommended for immersion in water or 90+ percent water soluble solutions.

Watlow Firerod Datasheet (EN)
Watlow: Your Heat Solutions Resource Brochure (EN)

Watlow Firerod Fiche Technique (FR)
Watlow: Vos Solutions de Chauffage Brochure (FR)
Back to Firerod Cartridge Heaters

Product Features

Nickel-chromium resistance wire
  • Precisely centered in the unit assures even, efficient distribution of heat to the sheath
Magnesium oxide insulation
  • Compacted to the proper density, results in high dielectric strength and contributes to faster heat-up
Incoloy® sheath
  • Resists corrosion from water
Metallurgically-bonded conductor pins
  • Ensures a trouble-free electrical continuity
Lead end with silicone rubber seal
  • Protects the heater against moisture contamination
Optional stainless steel fittings
  • Available for use in corrosive applications
Horizontal through the wall tank mounting
  • Makes setup faster
240 and 480V ~ (ac)
  • Provides wiring flexibility
Stock availability
  • Same day shipment on various 5/8 in. diameter heaters with 3⁄4 in. NPT


Product Specifications

  • Maximum operating temperature in water to 212°F (100°C) at atmospheric pressure
  • Maximum watt density to 300 W/in2 (46.5 W/cm2)
  • Maximum voltage to 480VAC


  • Plastic reclamation
  • Food preparation
  • Lab equipment