Metal Finishing Equipment

Overtemp Protectors – Heater Fuses

Thermal overload protectors, also called overtemp fuses are designed to shut off power to the heater in an overheating situation. When requesting a quote for a replacement fuse, please provide the following information:

  • Model number of the heater where the fuse is being used
  • Model number of the controller being used with the heater
  • Part number of the fuse – located on the fuse tag
  • Type of solution being heated


There are three types of thermal overload protectors (heater fuses):

  1. Protector 1 overtemperature control system utilizes a heat sensitive fuse to detect overheat conditions. The protector, placed inside a thermowell, positioned in contact with the heater sheath, will cut power to the heater in the event of low liquid.
  2. Protector 2 and Protector 3 systems provide the same reliable overtemperature protection as the Protector 1; however, the control systems feature a heat sensing thermostat. If the liquid level drops and the heater reaches a preset overheat heater can quickly be made operational by pushing the reset button on the control to restore power.
  3. Protector 3 is designed for flexible lead or high temperature fluoropolymer (PTFE) heater applications only.