over-the-side immersion heaters

How to choose the right over-the-side immersion heaters?

When it comes to heating large amounts of fluid in a way that is effective and affordable for your plant or facility, industrial immersion heaters are the only type of equipment that is capable of this task. Industrial over-the-side immersion heaters are versatile as well as extremely effective components used to regulate the temperature of process solutions, oils, heat transfer fluids, corrosive chemicals, and more. However, in order to obtain the full benefits of immersion heating, you must select the appropriate type for your specific application. By selecting a heater for your specific application, you will increase efficiency and output of your heater. In this blog, we’ll look across everything you need to know about over-the-side immersion heaters and show you how to choose the one that will best meet your needs.


Electric over-the-side immersion heaters are made of several bent tubular heating elements that are welded into a terminal housing. The heater runs along the side or parallel to the tank, which is inserted through the top of the tank. An over-the-side immersion heater is the best option when there is no way to install the heater through the side wall and there is only one way to do so from the top of the tank. As a result, the heater can be removed from the top without emptying the tank.

The hot length in these heaters needs to be carefully calculated as it is always submerged in the fluid. They are built to cover the largest possible area in the tank. According to customer needs, a variety of sizes and shapes—including L- and O-shaped can be offered. Over-the-side designs allow for ease of installation and removal for cleaning heaters and tanks. Additionally, they can withstand a variety of harsh environments, inside as well as outside.

Power ratings, shapes, and mounting techniques come in a numerous option to suit different kinds of applications. A thermocouple, RTD, or thermostat can be used to regulate the temperature as required. For enclosure, terminal boxes of IP 23 Standard and IP 66 Waterproof can be offered. Additionally, industrial over-the-side immersion heaters come in a variety of sheath materials for wide range of industrial applications.

How do over-the-side immersion heaters work?

Over-the-side immersion heaters consists of a heating element encased in a sheath, forming a tubular heating element. The whole assembly will be directly inserted at the top of the tank or through a side fitting. After supplying the power, electricity will flow through the heating element. This will generate heat that spreads throughout the medium to be heated. The sheath is heated by heating element when current passes through it, and the sheath in turn heats the liquid. The extent of heating depends on the conductivity of the jacket and sheath. The volume of liquid and power of the heater also have an impact on how quickly a medium heat up.

Liquids can be heated using indirect as well as direct heating. Direct heating involves inserting an over-the-side heater directly into the liquid. The heating element is then brought into contact with the fluid to be heated. In contrast, indirect heating involves inserting a heater into a pipe with a closed end and submerging it in the liquid. This method has the benefit of avoiding direct contact with the fluid, which reduces the risk of corrosion and contamination.

In order to avoid heater failure, the heater must not touch the tank’s bottom. As a result, sludge legs of at least 4 inches are required to keep the heater above the bottom surface.

over-the-side immersion heaters

What to consider before buying an immersion heater?

Now that you are aware of what an over-the-side immersion heaters are and how they operate, it is time to discuss the factors that will ensure that your heater operates as efficiently as possible and lasts for a very long time. These are some of the most crucial factors to take into account before buying industrial over-the-side immersion heaters.

  • The heater’s sheath material and element watt density must be appropriate for your application if you want it to last for a long time.
  • Finding the appropriate wattage, which is the amount of power your heater needs to function, is obviously in addition to considering these specifications.
  • Determining the viscosity and thermal conductivity of the fluid will also play a significant role in determining the efficiency of the heater.
  • Additionally, the size of the heater should only be chosen after confirming that the space available is adequate for installation.
  • Finally, temperature control and sensing mechanisms should be integrated into the heater if necessary for precise operation.

What are over-the-side immersion heaters used for?

They are ideal for applications in a wide range of industries due to the variety of design styles. Since the elements are completely submerged in the medium, their efficiency rating is close to 100%, giving it an edge over other heating systems. The uses for over-the-side heaters are very diverse, ranging from straightforward water heating or freeze protection to more complex setups for heating wax products that need a steady flow. A few of the specific uses for over-the-side immersion heaters in various industries are listed below.

  • They are frequently used in oil tanks to control and maintain the proper viscosity of the oil as well as in water tanks for improved freeze protection during the winter.
  • Other applications for it include heating plating baths, salts and acids, corrosive chemicals, molten salts, caustic solutions, etc.
  • Additionally, both the chemical as well as petroleum industries use it frequently.
  • Solvent degreasing is another fascinating application of over-the-side heaters.

Marathon is best seller of over-the-side immersion heaters in India

We are one of the top manufacturers and suppliers of industrial over-the-side immersion heaters in India, offering heaters of the highest standards with fastest possible delivery. We have several immersion heater options available in our manufacturing range. Our team will use their expertise to assist you in setting up the ideal immersion heater for your particular application. Along with providing guidance, we also build your immersion heater in-house to ensure that all of your specific requirements are met. The wattage as well as voltage rating are both configurable for all of our industrial over the side immersion heaters. Listed below are a few features of the over the side immersion heaters we manufacture in:

  • Rigid as well as light-weight construction.
  • Choices for terminal enclosures.
  • Portable and easy to install
  • Sludge legs to keep elements above the surface
  • Temperature control as well as sensing


With more than ten years of experience, Marathon manufactures over-the-side immersion heaters that meet all of your thermal heating needs using both custom as well as industry-standard designs. For your industrial heating needs, we engineer, design, and manufacture high-quality over-the-side heaters in custom sizes as required. In order to meet the demands of your thermal heating application, our engineers can help you find the best and most effective heating solution. Contact us today by mailing at