It is important to know the optimal startup procedure for immersion heating furnaces as improper startup may result in production delays, lower lifespan, and/or breakage of heater components. Below we have a step by step guide for how to do just this. For more information, contact us.

Optimal Startup Procedure for Immersion Heating Furnaces


  1. Close the furnace.
  2. Before you turn the power on:
    1. Set the heater thermocouple high limit at 1700 deg. F.
    2. Set the percentage of power to the heater at 15%.
  3. Turn the power on.
  4. Increase the power every 5 minuets by 5% until the temperature in the heater approaches 600 deg. F.
  5. As the furnace warms up, it will be necessary to reduce the power to the heater to avoid tripping the 1700 deg. high limit. (The power off and on switching that occurs from excessive tripping of the high limit over time is detrimental to the ceramic tube and the heater wire).
  6. Allow 48 hours of pre-heat before introducing metal to the furnace.
  1. Reduce the power to the heaters by 10%.
  2. After 15 minutes, add metal quickly to bring the level 3” above the top of the
  3. Turn the power to 90% and continue filling the furnace.
  4. Raise the heater thermocouple high limit to 1850 deg. F.
  5. The metal temperature will drop considerably before it begins to rise.
    If the heater approaches the high limit at 90% power you may increase the high
    limit to 1900 deg. F.


  1. After determining the percent of power required to maintain the bath temperature
    (usually not more than 70%) you should limit the maximum power to 20% more
    to give adequate recovery capability.
  2. A build-up on the protection tube will cause a temperature rise in the heater and
    heater failure. A spot build-up on the protection tube may cause a heater failure
    with no warning.
  3. Periodic cleaning of the protection tube is recommended for long life.
  4. The frequency for scraping the tubes is determined mostly by oxides from the break-down furnace and from alloy modifications.

Read more about our immersion heaters.

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Immersion Heating System Details

New Century Heaters has engineered our immersion heaters specifically for molten metal. These heaters coupled with specially designed protection tubes provide the most robust and efficient molten metal heat source in the industry.

Our immersion heating elements are made of heavy gage ICA wire on cast ceramic cores that guarantee wire spacing to evenly distribute the heat through high density, high conductivity, non-wetting protection tubes.

We use the heaviest gage wire in the industry to provide robust, long-lived heaters that can be operated up to 2,000 degrees Fahrenheit. The wire is recessed in separating groves that are precision cast in a ceramic core that is engineered to compliment the mating protection tube. Because of this, the coils can never touch each other and short out. Extra heavy leads are brought out and insulated away from the heater core to provide trouble free connections.

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If you are looking to replace your immersion heater found in a melting furnace,  contact us!