Wattco Inline Water Heaters In Depth

Overview of Inline Heaters

Wattco inline heaters are designed to enhance the performance of a regular immersion heater, heating up liquid solutions while maximizing efficiency. These units are ideally suited for heating pressurized fluids including water, oil, steam, and various gases.

Are you’re considering an inline heater for your industrial process application? Use this FAQ to help you determine if a Wattco inline heater is the most suitable option for your needs. When we receive requests from prospective clients we ask a concise yet elaborate set of questions. These qualify the clients’ needs and set up realistic expectations for how the inline heater’s procurement, how it will interface and interact with the rest of the production process at your facility, and what sort of maintenance and repair requirements can be expected.

Getting A Quote On A Wattco Inline Heater

With Wattco, procuring production process equipment is a consultative process. We work with you to exchange knowledge and ideas to get you the optimal solution for your heating needs. Below, we list the primary considerations and questions you should prepare to answer when asking for a quote. To save time and make the procurement process as efficient as possible for whoever is in charge of procurement, it helps to have answers to such questions on hand when contacting us.

If you require detailed specification about our inline circulation heaters, consult our online inline heater brochure as a convenient and easy reference. Also bear in mind that in the majority of cases we can get back to you with a quote within 24 hours, getting you the information you need to make a decision.  

1. What solution would the inline heater be heating?

Several characteristics of an inline heater’s construction depend on the state and properties of the medium being heated. Among the most important considerations are whether the medium is corrosive and its viscosity. Providing Wattco with specific information on the medium being heated allows us to recommend construction materials which won’t react adversely with the medium and will provide optimal heat transfer for improved production efficiency. 

See the table below for specific details about which sheath material is appropriate depending on the target medium.

Sheath Material

2. What is the required flow rate of the solution?

In order to make a sensible recommendation for the heater’s pump and construction material, we require detailed information on the required flow rate. This information is also required to make recommendations for the type of inlet and outlet nozzles and operating pressure.  

3. What is your required wattage for the inline heater?

Knowing the wattage required for your applications helps us select the proper power supply and heating element. The heating element’s construction material must be selected based on the watt density, the speed, and the target temperature.  

4. What voltage is required for your inline heater?

Voltage is another consideration regarding the unit’s power supply and material of the element.  

5. What phase does the heater need to be wired for?

Single-phase distribution is most common for electrical loads like heating or lighting, but exceptions do exist. If your application requires a different form of electrical power distribution be sure to let your Wattco representative know.  

6. Will the heater be deployed outdoors or indoors?

The environment in which an inline heater is meant to operate determines the type and degree of insulation as well as the wattage density requirements, since viscosity increases as temperature decreases. Be sure to disclose if the heater will be moved from interior to exterior operations. If the heater is intended for an outdoor application it must be built to withstand the prevailing climate in your region in order to function at full operational capacity for the optimal length of time.  

7. What is the ambient temperature in the place where the heater will be operating?

Ambient temperature refers to the temperature of the area immediately surrounding equipment, in this case an inline heater. Ambient temperature informs our recommendation of construction material, insulation, and heating element material. If you need a heater for outdoor use, please provide us with the average ambient temperature as accurately as possible.  

8. Is the unit going to be operating in a hazardous environment?

Knowing whether or not the inline heater will be required to operate in a hazardous environment is among the most crucial questions. Please specify in as great a level of detail as possible what the adverse conditions are. These conditions can range from inclement weather to radioactivity or toxic atmosphere.  

9. What temperature does the solution which the Inline heater will be heating need to reach?

The required temperature lets us know what voltage and watt density the heater needs to have, both of which are factors to consider when selecting the material for the element.  

10. How quickly does the solution need to achieve the required temperature?

Time constraint allows us to select the appropriate electric phase, watt density, and construction material. Flow rate also factors into this parameter.  

11. Do you need the heater to be skid mounted and mobile?

If you require a heater which can be moved around the facility it can be mounted on a skid for ease of movement.  

12. Do you require a control panel for your Inline heater?

Wattco control panels enable fast, responsive control of various variables of the heater including temperature, flow rate, and pressure.  Our control panels can be customized to fit a range of custom requirements and can be fitted with NEMA enclosures which protect the internal control components from virtually any hazards, contaminants, or adverse conditions.

General Principles of How Inline Heaters Work

Inline circulation heaters are all-in-one circulation heaters constructed of an immersion heating element mounted inside an insulated tank.

Factors to Consider While Selecting An Inline Heater

Consider the following factors to select the proper heater for your application. If you require recommendations or further clarification regarding these factors please contact a Wattco representative.

– The operating temperature the inline heater must operate at?

– The watt density of the heater’s heating element.

– The construction material of the inline heater’s sheath. The material depends on whether or not the heater will face exposure to corrosive or non-corrosive contaminants in the environment.

If the heater faces exposure to corrosive contaminants please also consider: 

  • The temperature of the corrodent.
  • How much aeration the corrodent receives.
  • The velocity of the corrodent.


Below we’ve listed the standard inline heater specifications to allow you to conveniently refer to them when making a purchasing decision.   – Wattco inline heaters employ flanged immersion heaters designed to handle the most rigorous manufacturing process requirements.

  • Standard sizes range from 2 – 14 inches of stainless steel, galvanized- carbon steel pipe body.
  • Weights range between 150 lbs. And 1200 lbs.
  • With/Without skids or control panels.
  • One unit can provide up to 650 kW of power.
  • Multiple phases are available: 120, 240, and 480V available in 1 phase and 575 or 660V 3 phase arrangements available.
  • Several types of NEMA enclosures are available for the heater’s installation:
    • General Purpose – NEMA 1
    • Moisture Resistant – NEMA 4
    • Explosion Resistant Terminal Enclosures – NEMA 7
  • The inlet and outlet tubing which the solution pumps through can be 0.430 in. DIA and 0.475 in. DIA made of copper, steel, or stainless steel sheath elements.
  • Wattco inline heaters can ship with or without a thermostat using thermocouples and/or digital temperature controllers.
  • Many inline heater models can come with UL, CSA, ASME, and other third-party certification approval, listing, or certification.  

If you require more custom specifications, contact us and let a Wattco representative know what your special needs.  We will do our best to accommodate your needs or recommend a custom inline heating solution.


Consider Wattco as your supplier of inline heaters, because when you choose Wattco, you get more than a heater. You also get access to an expert consultant who can help you optimize your manufacturing process by helping you pick the right heater and get the most of its features & benefits.   Inline Heater Design Features:

  • Flanges available in sizes up to 14 in. diameter.
  • Manufacturers can fit vessels with flanges made of carbon, steel, or stainless steel and pressure ratings between 150 and 2000 P.S.I.
  • Insulated and seamless vessels are available upon request.
  • Custom inline heating solutions available.
  • We can provide either North American or European sizes, wattage, or materials according to your needs.
  • Different components and terminal boxes are available upon request for heat protection and use in high-temperature conditions. Materials include steel or stainless steel, among others.  

The Benefits of Choosing an Inline Heater:  

  • Install your heater quickly and easily. No specialized knowledge required.
  • Mount an inline heater on a skid for ease of mobility and stability.
  • Don’t waste time on cleaning and repairs
  • Wattco inline heaters are easy to clean and built to last.
  • Save energy
  • Inline heaters are more efficient than most alternatives.
  • Consistently achieve uniform heat distribution.
  • Save space
  • greater output available in heat bundle which is smaller relative to other options.
  • Depend on even heat distribution, every time you use the heater.
  • Minimize heat loss at your facility.
  • Maximize dielectric strength.
  • Don’t worry about compatibility
  • All Wattco heaters are compatible with industrial piping and safety standards.  

Optional Features

A number of optional features are available with most Wattco inline heaters to better serve your ends and optimize your manufacturing process. Below is a short summary of optional features for your ease of reference.  

  • Wattco can build in controls, thermostats, or virtually any single pole device with a limit of 240V up to 30 Amps.
  • Built-in high-limit controls and thermostats are available.
  • If your heater has a voltage exceeding 240 V., a current over 30 amps, or a three phase supply, the thermostat functions as a pilot only. And so there is no factory wiring to other elements.  

Inline Heater Construction

Wattco Circulation heater labeledWattco’s line of inline heaters is designed for long-lasting, high-efficiency performance. Depending on the details of your industrial application you will need a heating component of various construction materials. Refer to the diagram to the right for a detailed account of inline heater construction.  

Generally, the heat from an electric inline heater leaves the heater instead of passing to the steam or liquid exchanger.  Be aware that even the heating element is in proper contact with the solution being heated, the heating element’s sheath temperature will continue to increase until it is close to equal with the heat being transferred in the process.  

Bear in mind that due to the laws of thermodynamics, heaters with low watt density tend to last longer than heaters which have high watt densities. This phenomena is especially common with liquids which are stagnant or very viscous. For this reason and others, low-density heaters tend to be more expensive than heaters which have high watt density.  


Wattco equipment uses custom designs for compatibility with standard sizing and construction. If you have special needs or requirements, alert a Wattco representative when requesting a quote.   Otherwise, every heater ships with detailed user’s guides and instructions on installation and use. Should you require installation assistance, be sure to let us know and we will do all we can to help with the installation.  

What It’s Like Working With Wattco

Your relationship with Wattco doesn’t end with the completion of a sale. We make ourselves available to you to answer questions and address concerns. As well as finding new ways for your heating equipment to optimize the efficiency of your process.   Wattco is also able to handle maintenance and repair tasks and the full range of Wattco products. We encourage you to contact us regarding your Wattco hardware whenever the need should arise.

Procuring Your Inline Heater

Looking for a quote on an inline heater? Request your quote now to get back we can get back to you within 24 hours. Please review the questions outlined above and have answers prepared in advance of placing your quote request.   To get your quote, call Wattco or fill out our request proposal form.  

About Wattco & What Makes Wattco Different

Wattco has been designing, manufacturing, and working with electric heating hardware products for a range of industries since 1969. Over the years, our offering has grown along with our range of international clients. With over 45 years in the industry, we have become committed to finding alternative, optimal heating solutions for companies in a range of industries all around the world.